Darunavir and Ritonavir Tablets

Indications

• Dry eye conditions
• Tear deficiency
• Keratoconjunctivitis sicca

Dosage

Children: Apply as required, typically in the form of eye drops.

Adults: Apply as required, typically in the form of eye drops.

Mechanism of action

Hypromellose acts by forming a viscous gel upon contact with the ocular surface, which helps to retain moisture and protect against irritants. This gel-like property enhances the stability of the tear film and reduces evaporation, thereby alleviating symptoms associated with dry eye conditions.

Pharmacodynamics

The pharmacodynamic effects of hypromellose are primarily related to its ability to mimic natural tears, providing lubrication to the ocular surface. This lubrication reduces friction during blinking and maintains corneal hydration, which is critical for ocular comfort and health. Its high viscosity also contributes to prolonged retention time on the eye surface.

Pharmacokinetics

Hypromellose is administered topically as eye drops and is not significantly absorbed systemically. The retention time of hypromellose on the ocular surface is enhanced due to its viscosity, allowing for extended relief of dry eye symptoms. The elimination of hypromellose occurs primarily through drainage from the eye and dilution by the natural tear fluid.

Adverse effects

• Temporary visual disturbance
• Eye irritation

Precautions

• Should not be used during contact lens wear
• Use with caution in patients with known hypersensitivity to any component of the formulation

Pregnancy

Hypromellose is generally considered safe for use during pregnancy. However, it should be used only if clearly needed and after consulting a healthcare provider.

Breast-feeding

Hypromellose is unlikely to affect breastfed infants when used as directed, but consultation with a healthcare provider is advisable.

Storage

Store in a cool, dry place away from direct sunlight. Once opened, use within a specified period as indicated on the packaging.

Formulations

• {'name': 'Teardew', 'concentration': '0.3%', 'form': 'eye drops', 'volume': '10 ml'}
• {'name': 'Xailin Hydrate', 'concentration': '0.3%', 'form': 'eye drops', 'volume': '10 ml'}
• {'name': 'AacuLose', 'concentration': '0.3%', 'form': 'eye drops', 'volume': '10 ml'}
• {'name': 'Artelac', 'concentration': '0.32%', 'form': 'eye drops', 'volume': '10 ml'}
• {'name': 'Lacrilube', 'concentration': '2 mg/g', 'form': 'eye ointment', 'volume': '3.5 g'}
• {'name': 'Celluvisc', 'concentration': '1%', 'form': 'eye drops', 'volume': '0.4 ml unit dose'}

Indications

• HIV infection in combination with other antiretroviral drugs in patients previously treated with antiretroviral therapy
• HIV infection in combination with other antiretroviral drugs in treatment-naive patients

Dosage

Children: For children weighing 14-20 kg: 0.5 tablet twice daily; for children weighing 30 kg and above: 1 tablet twice daily. Refer to BNF for Children for detailed dosing guidelines.

Adults: 800 mg once daily or 600 mg twice daily, depending on previous treatment history and viral load.

Mechanism of action

Darunavir functions by binding to the HIV-1 protease enzyme, which is critical for viral protein processing and maturation necessary for HIV replication. By inhibiting the protease, darunavir prevents the cleavage of Gag-Pol proteins in infected cells, thus halting the formation of mature and infectious virions. Its ability to interact with multiple sites on the protease enzyme contributes to its effectiveness, particularly against resistant strains of HIV.

Pharmacodynamics

As a protease inhibitor, darunavir effectively lowers HIV viral load and enhances CD4 cell counts when used in combination with ritonavir and other antiretroviral medications. This mechanism leads to a significant decrease in morbidity and mortality rates in patients with HIV infection, improving overall health outcomes.

Pharmacokinetics

Darunavir is well-absorbed following oral administration. It has a high protein binding rate, primarily to albumin and alpha-1 acid glycoprotein. The drug undergoes hepatic metabolism, primarily via the cytochrome P450 system, particularly CYP3A4, and has a half-life that allows for once or twice daily dosing. The pharmacokinetics may vary based on the presence of food and other medications.

Adverse effects

• rash
• nausea
• diarrhea
• headache
• fatigue
• hepatotoxicity
• gastrointestinal disorders
• depression
• memory loss
• gynaecomastia
• nephrolithiasis
• severe cutaneous adverse reactions (SCARs)

Interactions

• darunavir + cobicistat: increased risk of adverse reactions
• darunavir + ritonavir: synergistic effect on HIV suppression
• darunavir + raltegravir: unknown interaction, increased risk of rash

Precautions

• monitor liver function tests
• watch for signs of severe skin reactions
• caution in patients with a history of drug allergies
• monitor for signs of nephrolithiasis
• consider potential drug interactions with other antiretrovirals

Pregnancy

Darunavir is generally considered safe to use during pregnancy; however, it should be used under the guidance of a healthcare provider as part of a comprehensive antiretroviral therapy plan.

Breast-feeding

Darunavir is excreted in breast milk; the decision to breastfeed while on darunavir should involve a risk-benefit assessment with a healthcare provider.

Storage

Store at room temperature, protect from moisture and light. Keep out of reach of children.

Formulations

• Darunavir oral suspension 100 mg/ml
• Darunavir 400 mg tablets
• Darunavir 600 mg tablets
• Darunavir 800 mg tablets
• Darunavir 75 mg tablets
• Darunavir 150 mg tablets

Indications

• HIV infection in combination with other antiretroviral drugs

Dosage

Children: For children over 2 years of age

Adults: The typical adult dose of ritonavir is 100–200 mg taken 1–2 times a day. For high-dose ritonavir used as a booster, the recommended dose is 800/200 mg once daily, but this should only be used in patients with an HIV strain that has fewer than 3 mutations to protease inhibitors.

Mechanism of action

Ritonavir inhibits the HIV protease enzyme, which is crucial for the cleavage of the viral polyprotein precursors into functional proteins essential for the formation of infectious HIV particles. By binding to the active site of the protease, ritonavir prevents this cleavage, leading to the production of non-infectious viral particles. Additionally, ritonavir is a potent inhibitor of the cytochrome P450 CYP3A4 isoenzyme, which enhances the pharmacokinetic profile of other protease inhibitors by reducing their metabolism.

Pharmacodynamics

Ritonavir exhibits antiviral activity specifically against HIV-1 by preventing the function of the viral protease. This inhibition disrupts the normal life cycle of HIV, resulting in immature viral particles that cannot propagate infection. Ritonavir is generally administered in conjunction with other antiretroviral therapies to achieve a synergistic effect, enhancing the overall antiviral activity and therapeutic success.

Pharmacokinetics

Ritonavir is well-absorbed when taken orally, with peak plasma concentrations occurring approximately 2 to 4 hours post-administration. Its bioavailability is influenced by food intake. The drug is extensively metabolized in the liver, primarily by the CYP3A4 enzyme. Ritonavir has a half-life of about 3 to 5 hours in adults, requiring multiple daily doses to maintain effective plasma levels. The drug is excreted mainly in feces, with minimal renal excretion.

Contra-indications

• Severe hepatic impairment
• Severe renal impairment
• History of pancreatitis

Adverse effects

• Nausea
• Diarrhea
• Vomiting
• Abdominal pain
• Increased risk of infections
• Pancreatitis
• Hyperlipidemia
• Fat redistribution
• Liver enzyme elevation
• Cardiac conduction disorders
• Visual impairment
• Peripheral neuropathy
• Hypersensitivity reactions

Interactions

• Ritonavir + antipsychotics (second-generation): Severe (affects exposure)
• Ritonavir + clozapine: Severe (affects exposure)
• Ritonavir + benzodiazepines: Severe (increases exposure)
• Ritonavir + diazepam: Severe (increases exposure)
• Ritonavir + flurazepam: Severe (increases exposure)
• Ritonavir + clopidogrel: Severe (decreases efficacy)
• Ritonavir + glecaprevir: Severe (increases exposure)
• Ritonavir + opioids: Severe (increases risk of central nervous system toxicity)
• Ritonavir + pethidine: Severe (increases risk of central nervous system toxicity)
• Ritonavir + tepotinib: Severe (increases exposure)

Precautions

• Monitor liver function tests regularly
• Use with caution in patients with a history of cardiac conduction disorders
• Evaluate signs of pancreatitis, discontinue if diagnosed
• Avoid use in severe impairment of hepatic or renal function
• Consider potential for drug interactions due to CYP3A4 inhibition

Pregnancy

Use during pregnancy only if the potential benefit justifies the potential risk to the fetus. Ritonavir is classified as Category B.

Breast-feeding

Ritonavir is excreted in breast milk. Weigh the benefits of breastfeeding against the potential risks of HIV transmission or adverse effects to the infant.

Storage

Store at room temperature, away from moisture and heat. Keep out of reach of children.

Formulations

• Ritonavir 50 mg tablets

Indications

• Cerebral edema
• Elevated intracranial pressure
• Acute kidney injury
• Oliguria
• Glaucoma
• Renal function diagnostic aid

Dosage

Adults: For cerebral edema, administer 0

Mechanism of action

Mannitol elevates blood plasma osmolality, resulting in enhanced flow of water from tissues, including the brain and cerebrospinal fluid, into interstitial fluid and plasma. This action reduces cerebral edema and intracranial pressure. As a diuretic, it increases the osmolality of glomerular filtrate, leading to increased urinary excretion of water and preventing sodium and chloride reabsorption in the renal tubules. Mannitol also facilitates the urinary excretion of toxic substances and can help in assessing renal function by measuring glomerular filtration rate (GFR).

Pharmacodynamics

Mannitol is classified as an osmotic diuretic. It is chemically similar to other sugar alcohols but has a unique ability to promote diuresis by remaining unabsorbed in the renal tubules. Its use is indicated for conditions associated with increased body fluids, such as cerebral edema and glaucoma. Mannitol may be combined with other diuretics to enhance diuretic efficacy. Inhaled formulations are used in cystic fibrosis, though they may cause bronchospasm and hemoptysis.

Pharmacokinetics

Mannitol is freely filtered by the glomeruli with less than 10% tubular reabsorption, which allows for its urinary excretion rate to serve as a measurement of GFR. It does not undergo significant metabolism and is eliminated primarily through the kidneys. The onset of action occurs within 30 to 60 minutes after intravenous administration, with effects lasting for several hours. Administration may require monitoring of renal function and fluid balance.

Contra-indications

• Anuria
• Severe dehydration
• Severe renal impairment
• Intracranial bleeding

Adverse effects

• Asthenia
• Gastrointestinal disturbances
• Dry mouth
• Confusion
• Visual impairment
• Hypotension
• Electrolyte imbalances
• Pulmonary edema
• Hemoptysis (with inhalation use)
• Bronchospasm (with inhalation use)

Interactions

• Potassium-sparing diuretics may increase the risk of hyperkalemia
• Other diuretics may have additive effects
• Caution with nephrotoxic agents

Precautions

• Caution in patients with diabetes mellitus
• Caution in the elderly
• Caution in patients with gout
• Caution in patients with hepatic impairment
• Monitor renal function and electrolytes regularly
• May cause blue fluorescence of urine

Pregnancy

Manufacturer advises avoid due to potential toxicity in animal studies.

Breast-feeding

Manufacturer advises avoid due to lack of information available.

Storage

Store in a cool, dry place, away from light. Do not freeze.

Formulations

• Solution for injection
• Inhalation powder
• Oral solution

Indications

• Constipation
• Dietary fiber supplementation
• Irritable bowel syndrome
• Diverticular disease
• Weight management

Dosage

Children: Refer to appropriate guidelines for specific dosage; generally taken with adequate fluid intake.

Adults: Refer to appropriate guidelines for specific dosage; generally taken with adequate fluid intake.

Mechanism of action

Cellulose acts primarily as a bulk-forming laxative. It absorbs water in the intestines, which increases stool bulk and stimulates peristalsis, thus facilitating bowel movements. Additionally, cellulose is not digestible by human enzymes, leading to fermentation by gut bacteria, which may enhance gut health and alter gut microbiota composition.

Pharmacodynamics

Cellulose increases stool weight and frequency of bowel movements. It works by retaining water in the intestines, leading to softer stools and improved passage through the gastrointestinal tract. The bulking effect of cellulose can help alleviate constipation and promote overall digestive health. It may also play a role in cholesterol reduction and glycemic control through its effects on digestion and absorption of nutrients.

Pharmacokinetics

Cellulose is not absorbed into the bloodstream due to its indigestible nature. Instead, it passes through the gastrointestinal tract, where it adds bulk to the stool. Its fermentation by colonic bacteria produces short-chain fatty acids, which may have beneficial effects on colon health. The onset of action for cellulose as a laxative can vary but is generally within 24 to 72 hours after ingestion.

Adverse effects

• Bloating
• Flatulence
• Diarrhea
• Abdominal discomfort

Precautions

• Use with caution in patients with a history of gastrointestinal disorders.
• Monitor for potential allergic reactions in sensitive individuals.

Pregnancy

Cellulose is generally considered safe during pregnancy as it is a non-toxic, indigestible fiber.

Breast-feeding

Cellulose is also considered safe during breastfeeding; it is excreted in breast milk in negligible amounts.

Storage

Store in a cool, dry place away from direct sunlight.

Formulations

• Powder
• Capsules
• Tablets
• Granules

Indications

• Hypovolemic shock
• Severe burns
• Postoperative fluid replacement
• Sepsis
• Trauma management

Dosage

Children: Refer to established guidelines for specific dosing, as it varies based on the type of colloidal solution used and the clinical condition being treated.

Adults: Refer to established guidelines for specific dosing, as it varies based on the type of colloidal solution used and the clinical condition being treated.

Mechanism of action

Colloidal solutions work by maintaining oncotic pressure in the blood, thus helping to retain fluid within the vascular system. This is primarily due to the large molecular weight of the colloidal particles, which cannot easily pass through capillary walls. The presence of colloids in the blood helps to draw water into the circulation, increasing blood volume and improving tissue perfusion.

Pharmacodynamics

The pharmacodynamics of colloidal solutions are centered on their ability to exert osmotic pressure, which helps maintain blood volume and pressure. This effect is particularly important in conditions such as hypovolemia and shock, where fluid replacement is necessary to restore hemodynamic stability. The efficacy of colloidal solutions can vary depending on the type of colloid used, as well as the underlying clinical condition being treated.

Pharmacokinetics

Colloidal solutions are typically administered intravenously and their pharmacokinetics can vary based on the specific formulation. Generally, colloids are distributed throughout the vascular compartment and have a longer duration of action compared to crystalloids, as they remain in circulation longer. The elimination of colloids is primarily through the reticuloendothelial system, where they are metabolized or eliminated by the liver and spleen. Factors such as particle size and composition can influence their distribution and clearance.

Adverse effects

• Allergic reactions
• Injection site reactions
• Nausea
• Vomiting
• Headache
• Fever

Precautions

• Use with caution in patients with known allergies to any component of the formulation
• Monitor for signs of hypersensitivity during administration
• Consider volume overload in patients with cardiac or renal impairment

Pregnancy

The safety of colloidal solutions during pregnancy has not been established. Use only if the potential benefit justifies the potential risk to the fetus.

Breast-feeding

It is not known whether colloidal solutions are excreted in human milk. Caution should be exercised when administering to breastfeeding mothers.

Storage

Store at room temperature, protect from light, and do not freeze. Keep out of reach of children.

Formulations

• Colloidal silver
• Colloidal gold
• Colloidal iron
• Other metal colloids

Indications

• Used as a binder in tablet formulations
• Acts as a stabilizer in liquid formulations
• Serves as a film-forming agent in topical preparations

Dosage

Children: Refer to specific formulations for guidance; dosages will vary based on the formulation and therapeutic use.

Adults: Refer to specific formulations for guidance; dosages will vary based on the formulation and therapeutic use.

Mechanism of action

Copovidone acts primarily as a binder in solid dosage forms. It forms a cohesive gel in the presence of moisture, which helps in the agglomeration of powder particles, thus improving the mechanical strength and integrity of tablets. Additionally, copovidone can enhance drug solubility and dissolution rate, thereby facilitating better absorption of active pharmaceutical ingredients.

Pharmacodynamics

As a polymer, copovidone does not exert a pharmacological effect in the traditional sense but plays a crucial role in the pharmaceutical formulation process. It aids in the uniform distribution of active ingredients and can enhance the stability of formulations, thereby ensuring consistent therapeutic efficacy. Its properties allow for the sustained release of drugs when used in controlled-release formulations.

Pharmacokinetics

Copovidone is not absorbed in the gastrointestinal tract and therefore does not exhibit systemic pharmacokinetics. Instead, it remains in the gastrointestinal lumen, where it can affect the release and absorption of other co-administered drugs. Its degradation products are typically non-toxic and are excreted without causing harm to the body.

Adverse effects

• Hypersensitivity reactions
• Nausea
• Vomiting
• Diarrhea
• Abdominal pain

Precautions

• Use with caution in patients with known allergies to polyvinyl compounds
• Evaluate risk of allergic reactions in sensitive individuals

Pregnancy

Safety during pregnancy has not been established. Use only if clearly needed and potential benefits justify the risks.

Breast-feeding

It is not known whether copovidone is excreted in human milk. Caution is advised when administering to nursing mothers.

Storage

Store in a cool, dry place, protected from light. Keep out of reach of children.

Formulations

• Oral tablets
• Capsules
• Topical ointments

Indications

• Energy source
• Dietary fiber supplement
• Source of vitamins and minerals
• Antioxidant support

Dosage

Children: Corn can be introduced to children as part of a balanced diet. There is no specific paediatric dosage; it should be given according to age-appropriate dietary guidelines.

Adults: Corn can be consumed in various forms as part of a balanced diet. There is no specific adult dosage; intake should be based on dietary preferences and nutritional needs.

Mechanism of action

The primary component of corn is starch, which is a polysaccharide composed of glucose units. Upon ingestion, starch is broken down into glucose by enzymes such as amylase in the digestive system. The glucose is then absorbed into the bloodstream, providing energy to cells throughout the body. Corn also contains antioxidants such as lutein and zeaxanthin, which may help protect against oxidative stress and support eye health.

Pharmacodynamics

Corn is mainly metabolized for energy due to its high carbohydrate content. The dietary fiber in corn aids in digestion and promotes satiety. Additionally, the presence of vitamins and minerals contributes to overall health, supporting various bodily functions including immune response and bone health. The antioxidants in corn may help reduce inflammation and lower the risk of chronic diseases.

Pharmacokinetics

The digestion and absorption of corn depend on its form (whole kernel, cornmeal, corn syrup, etc.). Generally, carbohydrates are digested and absorbed relatively quickly, with glucose appearing in the bloodstream shortly after consumption. The fiber content can slow digestion and help maintain stable blood sugar levels. The bioavailability of nutrients from corn can vary based on processing methods, such as cooking or milling.

Pregnancy

Corn is generally considered safe during pregnancy. It provides essential nutrients such as fiber, vitamins, and minerals, but should be consumed in moderation as part of a balanced diet.

Breast-feeding

Corn is safe for consumption while breastfeeding. It can provide important nutrients, but it's advisable to monitor for any allergic reactions in infants.

Storage

Store corn in a cool, dry place. Fresh corn should be kept in the refrigerator and consumed within a few days for optimal freshness.

Formulations

• Fresh corn
• Canned corn
• Frozen corn
• Cornmeal
• Corn syrup
• Corn oil

Indications

• Used as an excipient in solid dosage forms
• Facilitates drug disintegration and dissolution

Dosage

Children: Refer to specific product formulation guidelines as crospovidone is used as an excipient and does not have a direct dosage.

Adults: Refer to specific product formulation guidelines as crospovidone is used as an excipient and does not have a direct dosage.

Mechanism of action

Crospovidone acts by rapidly absorbing water and swelling upon contact with moisture. This action leads to the disintegration of solid dosage forms, thus increasing the surface area of the active ingredients and promoting their dissolution and subsequent absorption in the gastrointestinal tract. It does not affect the pH of the formulation, ensuring that the active ingredients remain stable.

Pharmacodynamics

Crospovidone exhibits properties that enhance the bioavailability of active ingredients in pharmaceutical formulations. Its ability to rapidly disintegrate tablets and capsules leads to quicker release and absorption of the drug into systemic circulation. As a disintegrant, it aids in the effective delivery of drugs that may otherwise be poorly soluble.

Pharmacokinetics

Crospovidone itself is not absorbed systemically when administered orally. It remains in the gastrointestinal tract, where it performs its function as a disintegrant. The pharmacokinetic profile of drugs formulated with crospovidone may be influenced by the enhanced dissolution and absorption rates provided by this excipient.

Pregnancy

Crospovidone is considered to have low toxicity and is generally regarded as safe for use during pregnancy, but specific studies are limited.

Breast-feeding

There is insufficient data on the excretion of crospovidone in human milk, but it is deemed safe for use during breastfeeding.

Storage

Store in a cool, dry place away from light and moisture, in tightly closed containers.

Formulations

• Powder
• Tablets

Dosage

Children: Refer to specific formulations and clinical guidelines for dosing information as this can vary widely based on the context of use.

Adults: Refer to specific formulations and clinical guidelines for dosing information as this can vary widely based on the context of use.

Mechanism of action

Dibasic compounds often act by providing a buffering effect in biological systems, which helps to maintain physiological pH levels. They may also interact with various biological targets depending on their specific structure, influencing metabolic pathways and cellular functions.

Pharmacodynamics

The pharmacodynamics of dibasic compounds is highly variable and depends on their specific chemical structure and the context of their use. Generally, these compounds may alter the absorption and distribution of other drugs, modulate enzyme activity, or affect cellular signaling pathways through their interactions with biological molecules.

Pharmacokinetics

The pharmacokinetics of dibasic compounds can vary widely. Factors such as solubility, stability, and route of administration influence their absorption, distribution, metabolism, and excretion. Typically, dibasic compounds may be absorbed in the gastrointestinal tract and may undergo various metabolic processes depending on their specific nature.

Pregnancy

Dibasic compounds should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Consult with a healthcare provider.

Breast-feeding

Caution is advised when administering dibasic compounds to breastfeeding mothers. Consult with a healthcare provider.

Storage

Store in a cool, dry place away from light. Keep out of reach of children.

Indications

• Monitoring respiratory function
• Assessment of metabolic status
• Management of respiratory acidosis
• Management of respiratory alkalosis

Dosage

Children: Dosing for interventions related to carbon dioxide levels in pediatric patients should be guided by clinical protocols and the BNF for Children.

Adults: Dosing for interventions related to carbon dioxide levels is typically based on clinical assessment and individual patient needs. Refer to clinical guidelines for specific scenarios.

Mechanism of action

Carbon dioxide acts primarily as a signaling molecule in the body, influencing respiratory drive and blood pH. It is produced during cellular respiration and is a critical component of the bicarbonate buffering system, which helps maintain acid-base homeostasis. Elevated levels of CO2 in the blood stimulate ventilation in the lungs, increasing the rate of gas exchange and facilitating the removal of excess CO2.

Pharmacodynamics

The pharmacodynamic effects of dioxides, particularly carbon dioxide, are closely related to its concentration in the blood. As CO2 levels increase, it leads to respiratory acidosis, which can stimulate the respiratory centers in the brain to increase ventilation. Conversely, low levels of CO2 can cause respiratory alkalosis, potentially leading to decreased respiratory drive. CO2 also plays a role in vasodilation and can affect blood flow and pressure through its influence on smooth muscle tone.

Pharmacokinetics

Carbon dioxide is produced endogenously during metabolic processes and is transported in the bloodstream primarily in three forms: dissolved in plasma, as bicarbonate ions (HCO3-), and bound to hemoglobin. The half-life of CO2 in the bloodstream is very short due to its rapid exchange with alveolar gas in the lungs. The elimination of CO2 occurs through exhalation, making it a dynamic component of respiratory physiology.

Pregnancy

Data on the effects of dioxide during pregnancy are limited. Caution is advised due to potential risks associated with exposure.

Breast-feeding

Limited data are available regarding the excretion of dioxide in human milk. Caution is recommended.

Storage

Store in a cool, dry place, away from direct sunlight and moisture.

Dosage

Children: Refer to specific guidelines for dosing based on the clinical context, as ethanolate is primarily used as a reagent rather than a therapeutic agent.

Adults: Refer to specific guidelines for dosing based on the clinical context, as ethanolate is primarily used as a reagent rather than a therapeutic agent.

Mechanism of action

Ethanolate acts as a strong base, facilitating deprotonation reactions in organic synthesis. It can also act as a nucleophile, attacking electrophilic centers in various organic compounds, leading to the formation of new covalent bonds. This property makes it useful in the synthesis of esters, ethers, and other organic molecules.

Pharmacodynamics

As a strong base, ethanolate can increase the pH of solutions, affecting the ionization of other compounds. Its reactivity allows for the formation of various intermediates in chemical reactions, which can lead to diverse synthetic pathways in organic chemistry. However, specific pharmacodynamic effects in clinical settings are not well documented, as its primary use is in laboratory and industrial contexts.

Pharmacokinetics

Ethanolate is not typically administered in a clinical setting, so detailed pharmacokinetic data is limited. In general, when used in laboratory settings, its effects and interactions can vary depending on the specific organic compounds involved in the reaction. It is important to handle ethanolate with care due to its reactivity and potential hazards.

Pregnancy

There are no adequate and well-controlled studies in pregnant women. Use only if clearly needed.

Breast-feeding

Ethanolate is excreted in human milk, caution should be exercised when administering to a nursing woman.

Storage

Store in a cool, dry place, away from light. Keep out of reach of children.

Indications

• Used as an excipient in tablet formulations
• Used as a bulking agent in capsule formulations
• Used in food products as a thickener or stabilizer

Dosage

Children: Refer to specific product guidelines as dosage will depend on the formulation and the active ingredients.

Adults: Refer to specific product guidelines as dosage will depend on the formulation and the active ingredients.

Mechanism of action

Microcrystalline cellulose acts as a non-digestible filler that enhances the flow properties of powders during the manufacturing of tablets and capsules. It does not have a direct pharmacological action on the body but ensures that the active ingredients are effectively delivered to the patient.

Pharmacodynamics

As a non-active ingredient, microcrystalline cellulose does not exert pharmacodynamic effects typical of active pharmaceutical ingredients. Its primary role is to provide a stable and consistent matrix for the drug, facilitating the release of the active compound once ingested.

Pharmacokinetics

Microcrystalline cellulose is not absorbed in the gastrointestinal tract; it passes through the digestive system largely unchanged. It adds bulk to the stool, which may aid in promoting regular bowel movements. The substance is excreted in feces, where it contributes to dietary fiber intake.

Pregnancy

Data regarding the use of microcrystalline cellulose during pregnancy is limited. It is advisable to consult with healthcare professionals before use.

Breast-feeding

Microcrystalline cellulose is considered safe during breastfeeding, as it is not absorbed systemically.

Storage

Store in a cool, dry place away from direct sunlight and moisture.

Indications

• Antimicrobial agent
• Support for immune function
• Gastrointestinal health
• Emulsifying agent in food products

Dosage

Children: Refer to specific product guidelines or consult a healthcare provider, as dosing can vary based on the formulation and intended use.

Adults: Refer to specific product guidelines or consult a healthcare provider, as dosing can vary based on the formulation and intended use.

Mechanism of action

Monolaurate exhibits its antimicrobial activity primarily through disruption of lipid membranes of bacteria, viruses, and fungi. Its mechanism involves the incorporation into the lipid bilayer of microbial cell membranes, leading to increased permeability and eventual cell lysis. This action makes it effective against a wide range of pathogens, including Gram-positive and Gram-negative bacteria.

Pharmacodynamics

Monolaurate has been shown to possess antiviral, antibacterial, and antifungal properties. The compound works by destabilizing the lipid membranes of pathogens, which can lead to their death. Additionally, it may enhance the immune response by promoting the activity of immune cells, although the exact pathways involved are still being explored. The effects of monolaurate can vary based on the concentration used and the specific microorganisms targeted.

Pharmacokinetics

Monolaurate is absorbed in the gastrointestinal tract and is rapidly metabolized into free fatty acids and glycerol. The medium-chain fatty acids can be readily transported to the liver and utilized for energy or converted into ketone bodies. Its bioavailability can be influenced by dietary fats present in the meal, as fats can enhance the absorption of monolaurate. The elimination half-life and specific metabolic pathways in humans are not well characterized, necessitating further research.

Pregnancy

There is insufficient data to determine the safety of monolaurate during pregnancy. Caution is advised.

Breast-feeding

Limited information is available on the safety of monolaurate during breastfeeding. Consult a healthcare provider before use.

Storage

Store in a cool, dry place, away from direct sunlight and heat.

Formulations

• Capsules
• Powder
• Liquid

Indications

• Tablet coating
• Granule coating
• Improvement of drug stability
• Taste masking
• Aesthetic enhancement of pharmaceuticals

Dosage

Children: Dosage will depend on the specific formulation and active ingredients of the medication being coated. Refer to the specific product information for guidance.

Adults: Dosage will depend on the specific formulation and active ingredients of the medication being coated. Refer to the specific product information for guidance.

Mechanism of action

Opadry functions primarily as a coating polymer that adheres to the surface of tablets or granules, creating a protective layer. This layer can control the release of the active ingredient and protect it from environmental factors such as moisture and light. The specific composition of Opadry can vary, but it typically includes film-forming agents, plasticizers, and colorants that work together to achieve the desired coating characteristics.

Pharmacodynamics

The pharmacodynamics of Opadry is largely focused on its physical and chemical properties rather than specific biological interactions. The coating alters the dissolution characteristics of the drug, potentially leading to modified release profiles. This can enhance drug bioavailability or control the release rate of the active ingredient, thereby impacting the therapeutic effect.

Pharmacokinetics

As a coating agent, Opadry itself is not absorbed into the systemic circulation and does not have pharmacokinetic properties related to absorption, distribution, metabolism, or excretion of an active pharmaceutical ingredient. Its impact on pharmacokinetics is indirect, as it affects how the active drug is released and absorbed in the gastrointestinal tract.

Pregnancy

Opadry is a film-coating agent, and specific studies on its effects during pregnancy are not well-documented. Generally, it is advisable to use medications cautiously during pregnancy. Consult a healthcare provider for guidance.

Breast-feeding

Limited data are available regarding the safety of Opadry during breastfeeding. It is recommended to consult a healthcare provider before use.

Storage

Store in a cool, dry place away from direct sunlight and moisture. Keep out of reach of children.

Formulations

• Opadry OY - a coating system for oral solid dosage forms
• Opadry II - a polymer-based coating system for tablet and capsule applications

Dosage

Children: Refer to specific drug formulations and product labels as purified substances can vary widely in their use and dosing.

Adults: Refer to specific drug formulations and product labels as purified substances can vary widely in their use and dosing.

Mechanism of action

The mechanism of action for purified compounds varies widely depending on the specific substance. Generally, purified drugs exert their effects by interacting with specific biological targets, such as receptors, enzymes, or ion channels, leading to a desired therapeutic effect. This interaction can involve binding to receptors to activate or inhibit signaling pathways, modulating enzymatic activity, or altering physiological processes.

Pharmacodynamics

Pharmacodynamics describes the effects of a drug on the body and the relationship between drug concentration and effect. For purified drugs, this can involve dose-response relationships and the time course of their action. The purified form often enhances potency and reduces variability in response among patients, which can lead to more predictable therapeutic outcomes. The overall effect is determined by the drug's affinity for its target, the efficacy of the drug-receptor interaction, and the downstream signaling pathways activated as a result of this interaction.

Pharmacokinetics

Pharmacokinetics involves the absorption, distribution, metabolism, and excretion (ADME) of a drug. For purified substances, absorption can be more efficient due to the absence of impurities that may affect solubility or stability. Distribution may also be enhanced, leading to higher bioavailability. Metabolism can be influenced by the structure of the purified compound, as it may be metabolized more readily by liver enzymes. Excretion typically occurs through the kidneys or liver, depending on the molecular characteristics of the purified drug.

Pregnancy

Consult with a healthcare professional, as the safety of purified forms of medications during pregnancy may vary depending on the specific substance.

Breast-feeding

Consult with a healthcare professional, as the safety of purified forms of medications during breastfeeding may vary depending on the specific substance.

Storage

Store in a cool, dry place, away from light and moisture, and keep out of reach of children.

Indications

• Improvement of flow properties in powder formulations
• Preventing clumping in solid dosage forms
• Management of gastrointestinal disorders

Dosage

Children: Refer to specific formulation guidelines as silicified silica is typically used as an excipient and does not have a defined dosage.

Adults: Refer to specific formulation guidelines as silicified silica is typically used as an excipient and does not have a defined dosage.

Mechanism of action

Silicified silica acts by adsorbing moisture and preventing the clumping of powders. It also has the ability to absorb excess gastric acid, which can aid in the management of certain gastrointestinal conditions.

Pharmacodynamics

Silicified silica does not exert a direct pharmacological effect on body systems but improves the physical properties of pharmaceutical formulations. By promoting better flow and preventing caking, it enhances the bioavailability of active pharmaceutical ingredients (APIs).

Pharmacokinetics

Silica is not absorbed in the gastrointestinal tract and is excreted unchanged. Its pharmacokinetic profile is characterized by its inert nature and lack of systemic absorption, which allows it to function primarily at the site of administration.

Pregnancy

There is limited data on the use of silicified in pregnancy. Consult a healthcare provider before use.

Breast-feeding

It is unknown whether silicified is excreted in human milk. Caution is advised when administering to breastfeeding mothers.

Storage

Store in a tightly closed container, protected from moisture and light.

Indications

• Potential role in bone health
• Support for connective tissue formation
• May aid in mineral metabolism

Dosage

Children: There is no established clinical dosage for silicon in paediatric populations, as it is not classified as an essential nutrient.

Adults: There is no established clinical dosage for silicon in adults, as it is not classified as an essential nutrient.

Mechanism of action

Silicon is believed to enhance the synthesis of glycosaminoglycans and collagen, which are important for the structural integrity of connective tissues. It may also influence the activity of certain enzymes involved in bone mineralization, thus playing a role in maintaining bone density and health.

Pharmacodynamics

The pharmacodynamics of silicon is not fully elucidated; however, it is thought to involve the modulation of bone metabolism and the promotion of connective tissue health. Silicon may have a synergistic effect with other minerals, such as calcium and magnesium, aiding in their utilization and metabolism in the body.

Pharmacokinetics

The pharmacokinetics of silicon is complex, as it is not absorbed through typical gastrointestinal pathways. Instead, silicon is thought to be taken up in the form of silicates and then distributed throughout the body, particularly in connective tissues. The elimination of silicon occurs primarily through renal excretion, with some variations depending on dietary intake and individual metabolism.

Pregnancy

Silicon is generally considered safe during pregnancy, as it is a naturally occurring element in the human body. However, specific recommendations regarding supplementation should be followed based on the advice of a healthcare provider.

Breast-feeding

Silicon is present in breast milk in small amounts. Its safety during breastfeeding is generally regarded as acceptable, although supplementation should be approached with caution and under medical advice.

Storage

Silicon should be stored in a cool, dry place, protected from light and moisture. Follow specific storage recommendations provided by the manufacturer if available.

Indications

• Emulsifying agent in topical formulations
• Stabilizing agent in oral drug formulations
• Food industry applications as an emulsifier
• Cosmetic formulations

Dosage

Children: Refer to specific formulation guidelines for dosage recommendations.

Adults: Refer to specific formulation guidelines for dosage recommendations.

Mechanism of action

Sorbitan acts primarily as a surfactant and emulsifier. Its amphiphilic nature allows it to reduce the surface tension between oil and water, thereby facilitating the formation and stabilization of emulsions. The hydrophilic part of the sorbitan molecule interacts with water, while the lipophilic part interacts with oils, promoting the mixing of immiscible liquids.

Pharmacodynamics

As an emulsifier, sorbitan enhances the bioavailability of lipophilic drugs by aiding their dispersion in aqueous environments. This property is particularly valuable in formulations where uniform distribution of active ingredients is critical for efficacy. Sorbitan may also impact the release profiles of drugs from emulsified formulations, potentially affecting the onset of action.

Pharmacokinetics

Sorbitan is generally considered to be poorly absorbed when administered orally, leading to minimal systemic exposure. Its primary role is local, serving as an excipient in formulations rather than as an active therapeutic agent. Due to its emulsifying properties, it may enhance the solubility and absorption of other drugs in the gastrointestinal tract, but the absorption characteristics of sorbitan itself are limited. Metabolism and excretion details specific to sorbitan are not well-documented, as it typically functions in a non-systemic capacity.

Pregnancy

Sorbitan has not been well studied in pregnant women. Use during pregnancy should be based on a risk-benefit assessment.

Breast-feeding

Sorbitan is generally considered safe during breastfeeding, however, there is limited data available.

Storage

Store at room temperature, away from moisture and heat. Keep container tightly closed.

Formulations

• Sorbitan monooleate
• Sorbitan monostearate
• Sorbitan tristearate

Indications

• Nutritional supplementation
• Energy source in enteral nutrition
• Excipient in pharmaceutical formulations

Dosage

Children: Refer to specific guidelines or product inserts for dosing information, as it can vary based on the context of use.

Adults: Refer to specific guidelines or product inserts for dosing information, as it can vary based on the context of use.

Mechanism of action

Starch is broken down into glucose units by enzymes such as amylase during digestion. The glucose is then absorbed in the intestines and utilized for energy production in the body's cells. This pathway involves hydrolysis of the glycosidic bonds, converting starch into simpler sugars.

Pharmacodynamics

Starch primarily serves as an energy source. Its digestion and absorption lead to an increase in blood glucose levels, which provides energy for metabolic processes. In this context, it plays a crucial role in maintaining energy homeostasis in the body.

Pharmacokinetics

Starch is not absorbed in its polymeric form; it must first be enzymatically hydrolyzed into simpler sugars such as maltose and glucose. The digestion and absorption of starch occur predominantly in the small intestine, with glucose being readily absorbed into the bloodstream. The rate of absorption can vary depending on the type of starch and its physical form.

Adverse effects

• Allergic reactions
• Gastrointestinal discomfort
• Diarrhea
• Constipation

Precautions

• Use with caution in individuals with known allergies to starch or starch derivatives
• Monitor for gastrointestinal symptoms in patients with a history of digestive disorders

Pregnancy

Starch is generally considered safe for use during pregnancy. However, it should be consumed in moderation as part of a balanced diet.

Breast-feeding

Starch is deemed safe for nursing mothers when used in moderation as part of a balanced diet.

Storage

Store in a cool, dry place away from moisture and direct sunlight.

Formulations

• Powder
• Granules
• Tablets
• Suspensions

Indications

• Dry skin conditions
• Cosmetic formulations
• Emollient in topical creams and lotions
• Emulsifying agent in pharmaceutical preparations

Dosage

Children: For pediatric use, refer to specific product formulations and guidelines, as dosing may vary based on the formulation and concentration.

Adults: Stearyl alcohol is used topically in various formulations. Specific dosing is typically determined by the formulation and intended use, refer to product guidelines for detailed instructions.

Mechanism of action

Stearyl alcohol functions primarily as an emollient and emulsifier. It aids in the formation of stable emulsions by reducing the surface tension between oil and water phases, allowing for the creation of creams and lotions. Its hydrophobic tail interacts with lipids, while the hydroxyl group can form hydrogen bonds with water, enhancing moisture retention in the skin.

Pharmacodynamics

Stearyl alcohol acts by providing a protective barrier on the skin, reducing transepidermal water loss and enhancing hydration. Its emollient properties make it effective in softening and smoothing the skin, which can alleviate dryness and improve the overall appearance of the skin. Additionally, it can enhance the delivery of other active ingredients in topical formulations.

Pharmacokinetics

Stearyl alcohol is not significantly absorbed systemically when applied topically. Its primary action is local to the site of application, where it exerts its emollient effects. The compound is metabolized in the body to various fatty acids and alcohols, and it is excreted primarily through the skin and gastrointestinal tract, with minimal systemic exposure.

Pregnancy

Stearyl is generally considered safe for use during pregnancy; however, specific formulations should be evaluated for their ingredients.

Breast-feeding

Stearyl can be used while breastfeeding, but it's recommended to consult a healthcare provider for specific concerns regarding topical applications.

Storage

Store in a cool, dry place away from direct sunlight. Keep out of reach of children.

Formulations

• Cream
• Ointment
• Lotion

Pregnancy

No specific data available, consult a healthcare professional.

Breast-feeding

No specific data available, consult a healthcare professional.

Storage

Store in a cool, dry place away from light.

Mechanism of action

The HIV-1 protease enzyme is necessary for viral precursor protein processing and viral maturation in preparation for infection, and is therefore a target for antiretroviral therapy for HIV. Protease inhibitors are used as a part of highly active antiretroviral therapy (HAART) in patients diagnosed with HIV infection. It has been shown to effectively suppress the virus, leading to significantly decreased morbidity and mortality rates. Darunavir, a HIV protease inhibitor, prevents HIV replication through binding to the enzyme, stopping the dimerization and the catalytic activity of HIV-1 protease. In particular, it inhibits the cleavage of HIV encoded Gag-Pol proteins in cells that have been infected with the virus, halting the formation of mature virus particles, which spread the infection. The close contact that darunavir makes with the primary chains of the active site amino acids (Asp-29 and Asp-30) on the protease likely contributes to its potency and efficacy against resistant variants of HIV-1. Darunavir is known to bind to different sites on the enzyme: the active site cavity and the surface of one of the flexible flaps in the protease dimer. Darunavir can adapt to changes in the shape of a protease enzyme due to its molecular flexibility. Darunavir as a protease inhibitor inhibits the cleavage of HIV encoded gag-pol polyproteins in virus infected cells, thereby preventing the formation of mature and infectious new virions. It was selected for its potency against wild type HIV-1 and HIV strains resistant to currently approved protease inhibitors. Darunavir is an inhibitor of the HIV-1 protease. It selectively inhibits the cleavage of HIV encoded Gag-Pol polyproteins in infected cells, thereby preventing the formation of mature virus particles.

Pharmacodynamics

Darunavir is an inhibitor of the human immunodeficiency virus (HIV) protease, which prevents HIV viral replication. When administered with ritonavir in combination antiretroviral therapy, darunavir significantly decreases viral load and increases CD4 cell counts, decreasing the morbidity and mortality of HIV infection.

Mechanism of action

Mannitol is an osmotic diuretic that is metabolically inert in humans and occurs naturally, as a sugar or sugar alcohol, in fruits and vegetables. Mannitol elevates blood plasma osmolality, resulting in enhanced flow of water from tissues, including the brain and cerebrospinal fluid, into interstitial fluid and plasma. As a result, cerebral edema, elevated intracranial pressure, and cerebrospinal fluid volume and pressure may be reduced. As a diurectic mannitol induces diuresis because it is not reabsorbed in the renal tubule, thereby increasing the osmolality of the glomerular filtrate, facilitating excretion of water, and inhibiting the renal tubular reabsorption of sodium, chloride, and other solutes. Mannitol promotes the urinary excretion of toxic materials and protects against nephrotoxicity by preventing the concentration of toxic substances in the tubular fluid. As an Antiglaucoma agent mannitol levates blood plasma osmolarity, resulting in enhanced flow of water from the eye into plasma and a consequent reduction in intraocular pressure. As a renal function diagnostic aid mannitol is freely filtered by the glomeruli with less than 10% tubular reabsorption. Therefore, its urinary excretion rate may serve as a measurement of glomerular filtration rate (GFR). The exact mechanism of action of inhaled mannitol in the symptomatic maintenance treatment of cystic fibrosis remains unclear. It is hypothesized that mannitol produces an osmotic gradient across the airway epithelium that draws fluid into the extracellular space and alters the properties of the airway surface mucus layer, allowing easier mucociliary clearance. MANNITOL IS.../USED/ IN PROPHYLAXIS OF ACUTE RENAL FAILURE. IT IS USED FOR THIS PURPOSE IN CONDITIONS AS DIVERSE AS CARDIOVASCULAR OPERATIONS, SEVERE TRAUMATIC INJURY, OPERATIONS IN THE PRESENCE OF SEVERE JAUNDICE, AND MGMNT OF HEMOLYTIC TRANSFUSION REACTIONS. IN EACH OF THESE CONDITIONS, A PRECIPITOUS FALL IN THE FLOW OF URINE MAY BE ANTICIPATED EITHER AS THE RESULT OF AN ACUTELY REDUCED FILTRATION RATE OR FROM ACUTE CHANGES IN TUBULAR PERMEABILITY. THE LATTER MAY BE CONSEQUENCE OF THE PRESENCE OF NOXIOUS AGENT WITHIN THE TUBULAR FLUID IN EXCESSIVELY HIGH CONCN, IN SOME INSTANCES SUFFICIENT TO RESULT IN ACTUAL PRECIPITATION. IN THESE SITUATIONS, MANNITOL EXERTS OSMOTIC EFFECT WITHIN THE TUBULAR FLUID, INHIBITS WATER REABSORPTION, & MAINTAINS THE RATE OF URINE FLOW. ...CONCN OF TOXIC AGENT WITHIN TUBULAR FLUID DOES NOT REACH EXCESSIVELY HIGH LEVELS THAT OTHERWISE WOULD HAVE BEEN ACHIEVED BY MORE COMPLETE REABSORPTION OF WATER. ...EVEN THOUGH /GLOMERULAR/ FILTRATION RATE IS REDUCED, MANNITOL IS STILL FILTERED @ GLOMERULUS. THE TUBULAR IMPERMEABILITY TO MANNITOL IS NOT ALTERED BY ACUTE RENAL ISCHEMIA OF SHORT DURATION. HENCE, THE MANNITOL THAT IS FILTERED IS ALSO EXCRETED IN THE VOIDED URINE. UNREABSORBED SOLUTE LIMITS BACK DIFFUSION OF WATER. ...URINE VOL CAN BE MAINTAINED EVEN IN PRESENCE OF DECR GLOMERULAR FILTRATION.

Pharmacodynamics

Chemically, mannitol is an alcohol and a sugar, or a polyol; it is similar to xylitol or sorbitol. However, mannitol has a tendency to lose a hydrogen ion in aqueous solutions, which causes the solution to become acidic. For this reason, it is not uncommon to add a substance to adjust its pH, such as sodium bicarbonate. Mannitol is commonly used to increase urine production (diuretic). It is also used to treat or prevent medical conditions that are caused by an increase in body fluids/water (e.g., cerebral edema, glaucoma, kidney failure). Mannitol is frequently given along with other diuretics (e.g., furosemide, chlorothiazide) and/or IV fluid replacement. Inhaled mannitol has the possibility to cause bronchospasm and hemoptysis; the occurrence of either should lead to discontinuation of inhaled mannitol.

Mechanism of action

Ritonavic inhibits the HIV viral proteinase enzyme that normally cleaves the structural and replicative proteins that arise from major HIV genes, such as *gag* and *pol*. *Gag* encodes proteins involved in the core and the nucleocapsid, while *pol* encodes the the HIV reverse transcriptase, ribonuclease H, integrase, and protease. The *pol*-encoded proteins are initially translated in the form of a larger precursoe polypeptide, *gag-pol*, and needs to be cleaved by HIV protease to form other complement proteins. Ritonavir prevents the cleavage of the *gag-pol* polyprotein, which results in noninfectious, immature viral particles. Ritonavir is a potent inhibitor of cytochrome P450 CYP3A4 isoenzyme present both in the intestinal tract and liver. It is a type II ligand that perfectly fits into the CYP3A4 active site cavity and irreversibly binds to the heme iron via the thiazole nitrogen, which decreases the redox potential of the protein and precludes its reduction with the redox partner, cytochrome P450 reductase. Ritonavir may also play a role in limiting cellular transport and efflux of other protease inhibitors via the P-glycoprotein and MRP efflux channels. Unlike nucleoside antiretroviral agents, the antiviral activity of ritonavir does not depend on intracellular conversion to an active metabolite. Ritonavir and other HIV protease inhibitors (e.g., amprenavir, indinavir, lopinavir, nelfinavir, saquinavir) act at a different stage of the HIV replication cycle than nucleoside and nonnucleoside reverse transcriptase inhibitors, and results of in vitro studies indicate that the antiretroviral effects of HIV protease inhibitors and some nucleoside or nonnucleoside antiretroviral agents may be additive or synergistic. Ritonavir is a selective, competitive, reversible inhibitor of HIV protease. HIV protease, an aspartic endopeptidase that functions as a homodimer, plays an essential role in the HIV replication cycle and the formation of infectious virus. During HIV replication, HIV protease cleaves viral polypeptide products of the gag and gag-pol genes (i.e., p55 and p160) to form structural proteins of the virion core (i.e., p17, p24, p9, and p7) and essential viral enzymes (i.e., reverse transcriptase, integrase, and protease). By interfering with the formation of these essential proteins and enzymes, ritonavir blocks maturation of the virus and causes formation of nonfunctional, immature, noninfectious virions. Ritonavir is active in both acutely and chronically infected cells since it targets the HIV replication cycle after translation and before assembly. Thus, the drug is active in chronically infected cells (e.g., monocytes and macrophages) that generally are not affected by nucleoside reverse transcriptase inhibitors (e.g., didanosine, lamivudine, stavudine, zalcitabine, zidovudine). Ritonavir does not affect early stages of the HIV replication cycle; however, the drug interferes with production of infectious HIV and limits further infectious spread of the virus. While the complete mechanisms of antiviral activity of ritonavir have not been fully elucidated, ritonavir apparently inhibits replication of retroviruses, including human immunodeficiency virus type 1 (HIV-1) and 2 (HIV-2), by interfering with HIV protease. The drug, therefore, exerts a virustatic effect against retroviruses by acting as an HIV protease inhibitor.

Pharmacodynamics

Ritonavir is a protease inhibitor with activity against Human Immunodeficiency Virus Type 1 (HIV-1). Protease inhibitors block the part of HIV called protease. HIV-1 protease is an enzyme required for the proteolytic cleavage of the viral polyprotein precursors into the individual functional proteins found in infectious HIV-1. Ritonavir binds to the protease active site and inhibits the activity of the enzyme. This inhibition prevents cleavage of the viral polyproteins resulting in the formation of immature non-infectious viral particles. Protease inhibitors are almost always used in combination with at least two other anti-HIV drugs. Modern protease inhibitors require the use of low-dose ritonavir to boost pharmacokinetic exposure through inhibition of metabolism via the cytochrome P450 3A4 enzyme pathway.