AMOQ

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

• Malaria caused by Plasmodium species
• Toxoplasmosis, particularly in immunocompromised patients
• Adjunct treatment of autoimmunity-related conditions

Dosage

Adults: For the treatment of toxoplasmosis in adults, the recommended dosage is 50 mg once daily until delivery, usually in combination with sulfadiazine and

Mechanism of action

Pyrimethamine inhibits the dihydrofolate reductase enzyme in plasmodia, blocking the biosynthesis of purines and pyrimidines necessary for DNA synthesis and cell multiplication. This inhibition leads to failure in nuclear division during the formation of schizonts in erythrocytes and liver. Additionally, it has immunomodulatory effects by increasing oxidative stress, which may aid in the elimination of parasites.

Pharmacodynamics

As an antiparasitic compound, pyrimethamine is particularly effective against uncomplicated, chloroquine-resistant Plasmodium falciparum malaria and Toxoplasma gondii. It exhibits blood schizonticidal activity and some tissue schizonticidal effects, though it does not affect gametocytes. The selective toxicity towards parasites, contrasted with minimal effects on human cells, is due to differences in nucleic acid precursor requirements. Its effectiveness is notably enhanced when used in combination with sulfonamides.

Pharmacokinetics

Pyrimethamine is absorbed well after oral administration and undergoes hepatic metabolism. Its elimination half-life is variable but can be prolonged in cases of renal impairment. The drug is primarily excreted in urine, both as unchanged drug and metabolites. Caution is advised in patients with liver and renal impairment, and monitoring of blood counts is recommended during prolonged therapy due to the risk of haematological toxicity.

Contra-indications

• G6PD deficiency
• Severe renal impairment
• Severe hepatic impairment
• History of seizures
• Heart block (requires ECG monitoring during parenteral treatment)

Adverse effects

• Abdominal pain
• Agitation
• Agranulocytosis
• Anaemia
• Angioedema
• Asthma
• Diarrhoea
• Dizziness
• Fever
• Flushing
• Headache
• Hearing impairment
• Hypersensitivity reactions
• Loss of consciousness
• Muscle weakness
• Nausea
• Skin reactions
• Thrombocytopenia
• Tinnitus
• Vertigo
• Vomiting

Interactions

• Antiepileptics (increases risk of haematological toxicity)
• Fosphenytoin (increases risk of haematological toxicity)
• Phenytoin (increases risk of haematological toxicity)
• Phenobarbital (increases risk of haematological toxicity)
• Primidone (increases risk of haematological toxicity)
• Methotrexate (increases risk of adverse effects)
• Pemetrexed (increases risk of adverse effects)

Precautions

• Monitor blood counts during prolonged treatment
• Consider dose reduction in renal and hepatic impairment
• Caution in patients predisposed to folate deficiency
• Avoid large loading doses in patients with a history of seizures
• Use with caution in pregnancy (theoretical teratogenic risk in the first trimester)

Pregnancy

High doses are teratogenic in the first trimester; however, in malaria, the benefit of treatment may outweigh the risks.

Breast-feeding

Present in milk but not known to be harmful; adequate folate supplements should be given to the mother. Avoid breastfeeding during treatment of toxoplasmosis.

Storage

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

Formulations

• Daraprim 25 mg tablets
• Oral suspension

Indications

• Skin disinfection
• Preparation of skin before injections
• Cleansing minor wounds

Dosage

Children: Apply to the skin as required; consult product literature for specific guidance.

Adults: Apply to the skin as required for disinfection.

Mechanism of action

Alcohol exerts its antiseptic effect by denaturing proteins, disrupting cell membranes, and dehydrating microbial cells, leading to cell lysis and death.

Pharmacodynamics

Alcohol has broad-spectrum antimicrobial activity, effective against bacteria, fungi, and viruses. Its efficacy is influenced by concentration, with higher concentrations generally being more effective.

Pharmacokinetics

Alcohol is rapidly absorbed through the skin and mucous membranes. It is metabolized primarily in the liver, with a half-life that varies based on the individual's metabolic rate and the amount consumed.

Contra-indications

• Concomitant use with lithium
• Regular use in neonates
• Patients with severe burns when diathermy has been preceded by application of alcoholic skin disinfectants

Adverse effects

• Eye erythema
• Punctate keratitis
• Cytotoxicity
• Eye discolouration

Interactions

• Increases risk of visual disturbances with antiepileptics
• Increases concentration with methylphenidate
• Increases risk of facial flushing and skin irritation with topical pimecrolimus
• Increases concentration with retinoids
• Increases concentration with acitretin
• Increases risk of facial flushing and skin irritation with topical tacrolimus
• Decreases antidiuretic effect with vasopressin

Precautions

• Avoid regular application to inflamed or broken skin or mucosa
• Avoid broken skin
• Flammable

Pregnancy

Sufficient iodine may be absorbed to affect the fetal thyroid in the second and third trimester.

Breast-feeding

Avoid regular or excessive use.

Storage

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

Formulations

• Betadine 2.5% dry powder spray
• Industrial methylated spirit
• Povidone-Iodine 25 mg per 1 gram

Indications

• Management of alcohol withdrawal syndrome
• Antidote in methanol or ethylene glycol poisoning
• Used in some medical procedures as a disinfectant or antiseptic

Dosage

Children: Refer to specialist guidelines, as alcohol is not typically indicated for paediatric use and may be contraindicated.

Adults: Dosing varies widely depending on the context of use and individual factors. For alcohol withdrawal, benzodiazepines are often preferred over ethanol itself.

Mechanism of action

Ethanol primarily exerts its effects by enhancing the activity of gamma-aminobutyric acid (GABA) at the GABA-A receptor, leading to increased inhibitory neurotransmission. Additionally, it inhibits the excitatory neurotransmitter glutamate at the NMDA receptor, contributing to its depressant effects. Ethanol also influences the release of several neurotransmitters, including dopamine, which is associated with its rewarding properties.

Pharmacodynamics

Ethanol's effects are dose-dependent, resulting in relaxation, sedation, and impairment of cognitive and motor functions at moderate to high doses. At lower doses, it may produce euphoria and disinhibition. Chronic use can lead to tolerance, dependence, and alcohol use disorders, characterized by compulsive consumption despite negative consequences.

Pharmacokinetics

Ethanol is rapidly absorbed from the gastrointestinal tract, with peak blood alcohol concentrations typically occurring 30 to 90 minutes after ingestion. It is metabolized primarily in the liver by alcohol dehydrogenase and the microsomal ethanol-oxidizing system (MEOS). The elimination half-life of ethanol varies but is generally around 1 to 2 hours. Factors such as age, sex, body weight, and food intake can influence the pharmacokinetics of ethanol.

Contra-indications

• Hypersensitivity to ethanol
• Severe liver disease
• Pregnancy
• History of alcohol use disorder

Adverse effects

• Drowsiness
• Dizziness
• Nausea
• Vomiting
• Headache
• Impaired coordination
• Blackouts
• Alcohol poisoning
• Increased risk of accidents

Interactions

• CNS depressants (e.g., benzodiazepines, opioids) may enhance sedative effects
• Anticoagulants (e.g., warfarin) may have altered effects
• Disulfiram may cause unpleasant reactions when used with alcohol
• Certain antihistamines may have increased sedative effects

Precautions

• Use caution in patients with liver disease
• Monitor for signs of alcohol dependence
• Avoid consumption before driving or operating machinery
• Consider risks in patients with a history of mental health disorders

Pregnancy

Consumption of alcohol during pregnancy can lead to fetal alcohol spectrum disorders and should be avoided.

Breast-feeding

Alcohol can pass into breast milk; caution is advised and excessive consumption should be avoided.

Storage

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

Formulations

• Beverage alcohol (e.g., beer, wine, spirits)
• Topical antiseptics containing ethanol
• Alcohol-based hand sanitizers

Indications

• Malaria caused by Plasmodium falciparum
• Rheumatoid arthritis
• Lupus erythematosus

Mechanism of action

The exact mechanism of action of amodiaquine is not completely understood. It is believed to inhibit heme polymerase activity, leading to an accumulation of free heme, which is toxic to malarial parasites. Amodiaquine binds to free heme, preventing its conversion to a less toxic form, and this drug-heme complex disrupts membrane function within the parasite. Additionally, it may interfere with protein synthesis by binding to nucleoproteins and intercalating into double-stranded DNA, inhibiting DNA and RNA polymerase. Furthermore, it is known to concentrate in the digestive vacuoles of the parasites, increasing vacuolar pH and impairing the parasite's ability to metabolize hemoglobin.

Pharmacodynamics

Amodiaquine is effective against malaria and exhibits anti-inflammatory properties. It can depress cardiac muscle function, impair conduction, and produce vasodilation, which may lead to hypotension. Other side effects include respiratory depression, diplopia, dizziness, and nausea. While its effectiveness is comparable to that of chloroquine, the development of resistance to amodiaquine has been documented. The drug's adverse effects and potential for toxicity necessitate monitoring during treatment.

Pharmacokinetics

Amodiaquine is well absorbed after oral administration. It undergoes hepatic metabolism, with its active metabolite contributing to its antimalarial effects. The pharmacokinetics can be influenced by factors such as hepatic function and concurrent medications. The elimination half-life of amodiaquine may vary, and it is important to consider individual patient factors when determining dosing regimens.

Contra-indications

• Hypersensitivity to amodiaquine or any of its components
• Severe liver impairment
• History of retinopathy related to 4-aminoquinoline derivatives
• Severe hematological disorders, including agranulocytosis and aplastic anemia

Adverse effects

• Nausea
• Vomiting
• Diarrhea
• Dizziness
• Diplopia
• Hypotension
• Cardiac arrhythmias
• Hepatotoxicity
• Skin rashes
• Agranulocytosis

Interactions

• May enhance effects of anticoagulants
• Concomitant use with other antimalarials may increase risk of toxicity
• Caution with drugs that can cause hepatotoxicity
• May affect the metabolism of drugs that are substrates for CYP450 enzymes

Precautions

• Monitor liver function during treatment
• Use with caution in patients with a history of cardiovascular disease
• Assess for signs of hematological disorders
• Consider potential for cross-resistance with other 4-aminoquinoline derivatives

Pregnancy

Amodiaquine should be used in pregnancy only if the potential benefit justifies the potential risk to the fetus. It is advised to refer to local guidelines.

Breast-feeding

Amodiaquine is excreted in breast milk. Caution is advised when administering to breastfeeding mothers.

Storage

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

Formulations

• Tablets
• Oral suspension

Indications

• Metabolic acidosis
• Acid-base imbalance
• Urinary alkalinization
• Treatment of certain poisonings
• Cardiac arrest in the context of metabolic acidosis

Dosage

Children: Refer to the BNF for Children for specific pediatric dosages, as they depend on the clinical condition

Adults: Refer to local guidelines and BNF for specific dosing recommendations as they may vary based on clinical condition and severity. General adult dosing for bicarbonate may range from 1 to 2 mEq/kg IV initially, followed by maintenance doses as needed.

Mechanism of action

Bicarbonate acts as a buffer that neutralizes excess acids in the body. It dissociates in solution to produce bicarbonate ions (HCO3-) which can react with hydrogen ions (H+) to form carbonic acid (H2CO3), subsequently leading to the production of carbon dioxide (CO2) and water (H2O). This process helps to raise the pH of the blood and other fluids, counteracting acidosis. Bicarbonate is involved in several metabolic pathways, including the urea cycle and various biosynthetic pathways.

Pharmacodynamics

Bicarbonate's primary pharmacodynamic effect is its ability to buffer hydrogen ions, thus increasing blood pH. This is essential in conditions such as metabolic acidosis, where the body accumulates excess acid. By raising blood pH, bicarbonate can help alleviate symptoms associated with acidemia, such as fatigue, confusion, and shortness of breath. Its effects can also influence the renal and respiratory systems to regulate acid-base homeostasis.

Pharmacokinetics

Bicarbonate is rapidly absorbed from the gastrointestinal tract. It is distributed throughout the body fluids, and its effects can be seen within minutes of administration. The kidneys play a significant role in bicarbonate homeostasis by reabsorbing bicarbonate from urine and excreting hydrogen ions. The elimination half-life can vary, depending on the patient's metabolic state and renal function.

Pregnancy

Use with caution. Consult with a healthcare provider before use.

Breast-feeding

Use with caution. Consult with a healthcare provider before use.

Storage

Store in a cool, dry place away from light.

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

• Used as a disintegrant in tablet formulations
• Enhances the bioavailability of active pharmaceutical ingredients

Dosage

Children: Refer to the specific formulation guidelines, as dosage will vary based on the active ingredient and formulation type.

Adults: Refer to the specific formulation guidelines, as dosage will vary based on the active ingredient and formulation type.

Mechanism of action

Croscarmellose sodium works by swelling and absorbing water when it comes into contact with gastrointestinal fluids. This swelling leads to the rapid disintegration of the tablet or capsule matrix, facilitating the release and absorption of the active pharmaceutical ingredients.

Pharmacodynamics

Croscarmellose sodium is classified as a superdisintegrant. Its ability to rapidly disintegrate solid dosage forms can significantly enhance the dissolution rate of the active ingredient, which is crucial for achieving therapeutic effects in a timely manner.

Pharmacokinetics

Croscarmellose sodium is not absorbed in the gastrointestinal tract and does not exert pharmacological effects in the body. It is considered non-toxic and is excreted unchanged. Its main role is as an excipient, influencing the formulation's characteristics rather than the pharmacokinetics of the active ingredients.

Precautions

• Use with caution in patients with known hypersensitivity to croscarmellose or its components.

Pregnancy

Safety in pregnancy has not been established. Use only if clearly needed.

Breast-feeding

Caution is advised when using during breastfeeding, as safety has not been established.

Storage

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

Formulations

• Powder
• Granules

Indications

• Used as an excipient in pharmaceutical formulations
• Improves solubility and stability of active ingredients
• Facilitates drug absorption

Dosage

Children: Refer to specific product guidelines as hydroxypropyl is typically used as an excipient and not dosed independently.

Adults: Refer to specific product guidelines as hydroxypropyl is typically used as an excipient and not dosed independently.

Mechanism of action

Hydroxypropyl functions primarily as a solubilizing agent, which aids in the dissolution of poorly soluble drugs. It interacts with water and other solvents to improve the dispersion of pharmaceutical compounds, thereby enhancing their bioavailability. Hydroxypropyl may also facilitate the permeability of drug molecules through biological membranes, contributing to their overall efficacy.

Pharmacodynamics

The pharmacodynamics of hydroxypropyl relate to its role in improving the physicochemical properties of drug formulations. By increasing solubility and stability, hydroxypropyl can enhance the absorption of drugs administered via various routes, including oral and topical. Its non-toxic nature allows for safe incorporation into formulations, making it suitable for a wide range of applications.

Pharmacokinetics

The pharmacokinetics of hydroxypropyl have not been extensively studied as it primarily acts as an excipient rather than an active pharmaceutical ingredient. When used in formulations, it is typically not absorbed into systemic circulation in significant amounts, thereby minimizing potential systemic effects. Hydroxypropyl is generally regarded as safe when used in appropriate amounts in drug formulations.

Pregnancy

Hydroxypropyl is not classified for use during pregnancy, and its safety has not been established. Caution is advised.

Breast-feeding

There is limited information on the excretion of hydroxypropyl in human milk. Caution is advised when administering to breastfeeding women.

Storage

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

Indications

• Disinfection of skin before procedures
• Antiseptic for minor cuts and abrasions
• Surface disinfectant in healthcare settings
• Solvent for pharmaceutical preparations

Dosage

Children: For topical application, the same concentration of isopropyl alcohol may be used as for adults. Refer to specific guidelines for application in children.

Adults: For topical use, apply isopropyl alcohol to the affected area as needed. For disinfection, use 70% isopropyl alcohol for effective antimicrobial action.

Mechanism of action

Isopropyl alcohol acts primarily by denaturing proteins and dissolving lipids. This disruption of the cell membrane and protein structures in microorganisms leads to cell lysis and ultimately the death of the pathogens. It is particularly effective against enveloped viruses, as the alcohol can disrupt the lipid bilayer of the viral envelope.

Pharmacodynamics

The pharmacodynamic properties of isopropyl alcohol are largely associated with its concentration and the duration of exposure. At concentrations of 60-90%, it exhibits potent antimicrobial activity. The mechanism involves dehydration of microbial cells and denaturation of proteins, which collectively contribute to its efficacy as a disinfectant.

Pharmacokinetics

Isopropyl alcohol is readily absorbed through the skin and mucous membranes. Once absorbed, it is metabolized primarily in the liver to acetone, which is then eliminated via urine. The peak plasma concentration occurs within 30 minutes to 2 hours after exposure, and the elimination half-life ranges from 2 to 4 hours, depending on the dosage and route of administration.

Adverse effects

• Headache
• Nausea
• Dizziness
• Skin irritation
• Respiratory depression in high concentrations

Precautions

• Use with caution in patients with respiratory conditions
• Avoid contact with skin and eyes
• Ensure adequate ventilation when used in high concentrations

Pregnancy

Isopropyl alcohol should be used with caution during pregnancy. Limited data is available on its safety.

Breast-feeding

Isopropyl alcohol is not recommended during breastfeeding due to potential risks.

Storage

Store in a cool, dry place away from heat sources. Keep tightly closed.

Formulations

• Isopropyl alcohol solution (e.g., 70% isopropyl alcohol)
• Isopropyl alcohol wipes
• Isopropyl alcohol gel

Indications

• Antiseptic for skin disinfection
• Solvent in pharmaceutical formulations
• Cleaning agent in laboratories and healthcare settings

Dosage

Children: For pediatric use, consult specific guidelines in the BNF for Children, as dosing may vary based on age, weight, and clinical circumstances.

Adults: For skin antisepsis, apply isopropyl alcohol topically in a concentration of 70% to the affected area. Dosage may vary based on clinical indication and setting.

Mechanism of action

Isopropyl alcohol works primarily as an antiseptic by denaturing proteins and disrupting cell membranes of bacteria, viruses, and fungi, leading to cell lysis and death. Its efficacy is enhanced by the presence of water, which facilitates the penetration of the alcohol into microbial cells.

Pharmacodynamics

Isopropyl alcohol exhibits a rapid onset of action against a variety of pathogens, including gram-positive and gram-negative bacteria, fungi, and some viruses. Its antimicrobial activity is concentration-dependent, with higher concentrations generally providing a broader spectrum of activity. It is commonly used in concentrations ranging from 60% to 90%, with 70% being optimal for disinfection due to its ability to penetrate the cell wall effectively.

Pharmacokinetics

Isopropyl alcohol is readily absorbed through the skin and mucous membranes. After absorption, it is metabolized primarily in the liver to acetone, which is then further metabolized and excreted, mostly via urine. The elimination half-life of isopropyl alcohol varies but is typically around 2 to 3 hours. Its effects can be influenced by factors such as dosage, route of exposure, and individual metabolic differences.

Pregnancy

Isopropyl alcohol should be used with caution during pregnancy. It is a category C drug, indicating that risk cannot be ruled out.

Breast-feeding

Caution is advised when using isopropyl alcohol during breastfeeding, as it is not known if it is excreted in human milk.

Storage

Isopropyl alcohol should be stored at room temperature, away from heat and flame. Keep the container tightly closed and in a well-ventilated area.

Formulations

• Isopropyl alcohol 70% solution
• Isopropyl alcohol 99% solution

Indications

• Topical antiseptic for skin disinfection
• Surgical scrubs and hand sanitizers
• Wound care management
• Pharmaceutical excipient in solid and liquid formulations

Dosage

Children: Refer to specific product guidelines for pediatric dosing recommendations, as doses can vary based on formulation and intended use.

Adults: Refer to specific product guidelines for dosing recommendations, as doses can vary based on the formulation and intended use.

Mechanism of action

Povidone acts by forming a complex with iodine when used as an antiseptic, which releases iodine slowly to exert its antimicrobial effect. The iodine disrupts microbial cell walls and interferes with protein synthesis, leading to cell death. Additionally, as a polymer, povidone can enhance drug solubility and stability by forming a hydrophilic matrix.

Pharmacodynamics

Povidone has a broad spectrum of antimicrobial activity against bacteria, viruses, and fungi. Its antiseptic properties are primarily due to the release of iodine, which is effective in reducing microbial load and preventing infection. The polymer's ability to bind to various substances allows it to be utilized in formulations that require improved stability and solubility.

Pharmacokinetics

Povidone is not absorbed systemically when applied topically, as it remains localized at the site of application. Its pharmacokinetics are largely dependent on the formulation and route of administration, with the polymer being metabolized by hydrolysis and excreted in urine as low-molecular-weight compounds. The release and activity of iodine are influenced by the concentration of povidone and the presence of organic matter.

Adverse effects

• Local irritation
• Allergic reactions
• Skin rashes
• Hypersensitivity reactions

Precautions

• Use with caution in patients with known allergies to iodine or povidone-iodine
• Avoid use in deep puncture wounds or serious burns

Pregnancy

Povidone is generally considered safe for use during pregnancy, but it is advisable to consult a healthcare professional before use.

Breast-feeding

Povidone is considered safe during breastfeeding, but it is recommended to consult a healthcare professional.

Storage

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

Formulations

• Topical solution
• Ointment
• Surgical scrub
• Gauze impregnated with povidone-iodine

Indications

• Caloric reduction in food and beverages
• Management of diabetes
• Weight management

Dosage

Children: Refer to the BNF for Children for specific guidelines on the use of sucralose in pediatric populations.

Adults: Sucralose is typically used in food and beverage products as a sweetener. There are no specific dosage recommendations for adults, as it is used according to taste preference and product formulation.

Mechanism of action

Sucralose acts as a positive allosteric modulator of the human sweet taste receptor. It interacts with the T1R taste receptor family, particularly enhancing the sweetness perception by binding to the hinge region of the receptor. This interaction induces a conformational change that stabilizes the active state of the receptor, increasing its responsiveness to sweet stimuli. This mechanism allows sucralose to mimic the taste of sugar without the associated caloric intake.

Pharmacodynamics

As a non-nutritive sweetener, sucralose does not undergo metabolic processing in the body, which means it does not contribute to energy intake. It provides intense sweetness at low concentrations, stimulating the sweetness receptors in the taste buds. The pharmacodynamic profile indicates minimal physiological effects beyond taste perception, making it suitable for dietary use without impacting blood glucose levels.

Pharmacokinetics

Sucralose is poorly absorbed in the gastrointestinal tract, with an estimated absorption rate of less than 15%. The majority of ingested sucralose is excreted unchanged in the urine. The elimination half-life is not well defined due to its minimal absorption, but it is generally considered to have a rapid clearance from the body. The pharmacokinetic properties support its use as a safe alternative to sugar for those managing caloric intake.

Pregnancy

Sucralose is generally considered safe during pregnancy, but it is recommended to consult a healthcare provider.

Breast-feeding

Sucralose is also considered safe during breastfeeding, although it is advisable to seek medical advice.

Storage

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

Formulations

• Granulated sucralose
• Liquid sucralose
• Tablets

Indications

• Diabetes management
• Weight management
• Dietary restrictions due to caloric intake
• Use in foods and beverages as a sugar substitute

Dosage

Children: Refer to specific product guidelines for appropriate use, as sucralose is used as a sweetener rather than a medication.

Adults: Refer to specific product guidelines for appropriate use, as sucralose is used as a sweetener rather than a medication.

Mechanism of action

Sucralose works by binding to the sweet taste receptors on the tongue, primarily the T1R2 and T1R3 receptors, leading to the sweet sensation. Unlike sugar, sucralose is not broken down by the body, which prevents it from contributing to caloric intake. Its molecular structure, modified by the substitution of hydroxyl groups with chlorine atoms, enhances its sweetness and resistance to digestion.

Pharmacodynamics

Sucralose exhibits a high sweetness potency with no caloric value. It does not induce insulin secretion or affect blood glucose levels, making it a viable alternative for individuals with diabetes or those managing caloric intake. Sucralose has a rapid onset of sweet taste perception and a prolonged duration of sweetness, which can enhance the palatability of food and beverages without the associated caloric load.

Pharmacokinetics

Sucralose is poorly absorbed by the gastrointestinal tract; approximately 85% of ingested sucralose passes through the body unchanged, while a small portion is absorbed and excreted in the urine. Its half-life is relatively short due to rapid excretion, and it does not accumulate in the body. The unabsorbed portion contributes to its non-nutritive properties.

Adverse effects

• Gastrointestinal disturbances
• Headaches
• Allergic reactions

Precautions

• Use with caution in individuals with phenylketonuria due to potential effects on metabolism
• Monitor for gastrointestinal symptoms in sensitive individuals

Pregnancy

Considered safe for use during pregnancy, however, moderation is advised.

Breast-feeding

Considered safe for use while breastfeeding, though it is advisable to consult a healthcare provider.

Storage

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

Formulations

• Granulated sweetener
• Tablets
• Liquid preparations

Indications

• Treatment of malaria caused by Plasmodium falciparum
• Prevention of malaria in individuals traveling to endemic areas

Dosage

Children: Refer to BNF for Children for specific dosing information.

Adults: Refer to BNF for specific dosing information.

Mechanism of action

Sulfadoxine acts as an antimetabolite by competitively inhibiting the enzyme dihydropteroate synthase, which is crucial for the synthesis of folic acid from para-aminobenzoic acid (PABA). This inhibition disrupts the folic acid production necessary for DNA synthesis and cellular growth in the Plasmodium species, particularly P. falciparum, thereby impairing its ability to reproduce.

Pharmacodynamics

Sulfadoxine's inhibition of dihydropteroate synthetase leads to a decrease in folic acid levels within the parasite. Folic acid is essential for the synthesis, repair, and methylation of DNA, and its deficiency hampers the growth and replication of Plasmodium falciparum, thereby aiding in the treatment of malaria.

Pharmacokinetics

Sulfadoxine is well-absorbed after oral administration, with peak plasma concentrations typically reached within 4 to 6 hours. It has a long half-life, allowing for once-daily dosing in many cases. The drug is metabolized in the liver and excreted primarily via the kidneys. Its pharmacokinetic profile supports its use in combination therapies for malaria, as it maintains therapeutic levels over extended periods.

Contra-indications

• Hypersensitivity to sulfadoxine or other sulfonamides
• Severe liver or kidney impairment
• Pregnancy at term
• Infants under 2 months of age

Adverse effects

• Nausea
• Vomiting
• Rash
• Fever
• Anemia
• Leukopenia
• Thrombocytopenia
• Hepatotoxicity
• Stevens-Johnson syndrome

Interactions

• May enhance the effects of anticoagulants such as warfarin
• May interact with methotrexate, increasing its toxicity
• May reduce the effectiveness of certain oral contraceptives

Precautions

• Monitor for signs of hypersensitivity reactions
• Use cautiously in patients with G6PD deficiency
• Assess renal function prior to and during therapy

Pregnancy

Use is contraindicated at term due to the risk of kernicterus in the neonate. Caution is advised during the first and second trimesters.

Breast-feeding

Sulfadoxine is excreted in breast milk; caution is advised when administering to breastfeeding mothers.

Storage

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

Formulations

• Sulfadoxine 500 mg tablets
• Sulfadoxine/pyrimethamine combination tablets

Dosage

Children: Refer to the specific drug monograph in the USP NF for paediatric dosing information.

Adults: Refer to the specific drug monograph in the USP NF for adult dosing information.

Mechanism of action

USP NF does not refer to a specific active ingredient or therapeutic agent. Rather, it encompasses a broad range of substances, each with its own unique mechanism of action depending on the specific drug referenced. Generally, drugs listed in the USP NF may act through various pathways, including receptor binding, enzyme inhibition, and modulation of ion channels, among others.

Pharmacodynamics

Pharmacodynamics will vary widely depending on the specific drug. Pharmacodynamics typically involves the study of drug effects and their mechanisms at the cellular level, including receptor interactions, signal transduction pathways, and the resultant physiological response. Each drug will have its own profile based on its chemical structure and target sites.

Pharmacokinetics

Pharmacokinetics also varies depending on the specific drug. It involves the study of the absorption, distribution, metabolism, and excretion (ADME) of drugs. Factors such as the route of administration, solubility, protein binding, and half-life will influence how a drug behaves in the body. For precise pharmacokinetic data, reference should be made to the specific monograph for the drug in question within the USP NF.

Pregnancy

Safety in pregnancy has not been established. Use only if potential benefit justifies the potential risk to the fetus.

Breast-feeding

Caution is advised; it is not known whether this drug is excreted in human milk.

Storage

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

Mechanism of action

Ethanol affects the brain’s neurons in several ways. It alters their membranes as well as their ion channels, enzymes, and receptors. Alcohol also binds directly to the receptors for acetylcholine, serotonin, GABA, and the NMDA receptors for glutamate. The sedative effects of ethanol are mediated through binding to GABA receptors and glycine receptors (alpha 1 and alpha 2 subunits). It also inhibits NMDA receptor functioning. In its role as an anti-infective, ethanol acts as an osmolyte or dehydrating agent that disrupts the osmotic balance across cell membranes. ... Ethanol is known to affect a large number of membrane proteins that participate in signaling pathways such as neurotransmitter receptors, enzymes, and ion channels, and there is extensive evidence that ethanol interacts with a variety of neurotransmitters. The major actions of ethanol involve enhancing the inhibitory effects of gamma-aminobutyric acid (GABA) at GABAa receptors and blockade of the N-methyl-D-aspartate (NMDA) subtype of glutamate, an excitatory amine acid (EAA) receptor. Animal studies indicate that the acute effects of ethanol result from competitive inhibition of glycine binding to NMDA receptor and disruption of glutamatergic neurotransmission by inhibiting the response of the NMDA receptor. Persistent glycine antagonism and attenuation of glutamatergic neurotransmission by chronic ethanol exposure results in tolerance to ethanol by enhancing EAA neurotransmission and NMDA receptor upregulation. The latter appears to involve selective increases in NMDA R2B subunit concentrations and other molecular changes in specific brain loci. The abrupt withdrawal of ethanol thus produces a hyperexcitable state that leads to the ethanol withdrawal syndrome and excitotoxic neuronal death. GABA-mediated inhibition, which normally acts to limit excitation, is eliminated during ethanol withdrawal syndrome and further intensifies this excitation. In addition, NMDA receptors function to inhibit the release of dopamine in the nucleus accumbens and mesolimbic structures, which modulate the reinforcing action of addictive xenobiotics such as ethanol. By inhibiting NMDA receptor activity, ethanol could increase dopamine release from the nucleus accumbens and ventral tegmental area and could thus create dependence. Chronic ethanol administration also results in tolerance, dependence, and an ethanol withdrawal syndrome, mediated, in part, by desensitization and or downregulation of GABAa receptors. The development of alcoholic ketoacidosis (AKA) requires that a combination of physical and physiologic events occur. The normal response to starvation and depletion of hepatic glycogen stores is for amino acids to be converted to pyruvate. Pyruvate can serve as a substrate for gluconeogenesis, be converted to acetyl-CoA, which can enter the Krebs cycle or can be utilized in various biosynthetic pathways (eg, fatty acid, ketone bodies, cholesterol, and acetylcholine) ... Ethanol metabolism generates NADH, resulting in an excess of reducing potential. This high redox state favors the conversion of pyruvate to lactate, diverting pyruvate from being a substrate for gluconeogenesis. To compensate for the lack of normal metabolic substrates, the body mobilizes fat from adipose tissue and increased fatty acid metabolism as an alternative source of energy. This response is mediated by a decrease in insulin and an increased secretion of glucagon, catecholamines, growth hormone, and cortisol. Fatty acid metabolism results in the formation of acetyl-CoA and it combines with the excess acetate that is generated from ethanol metabolism to form acetoacetate. Most of the acetoacetate is reduced to beta-hydroxybutyrate due to the excess reducing potential or high redox state of the cell. Volume depletion interferes with the renal elimination of acetoacetate and beta-hydroxybutyrate, and contributes to the acidosis. An elevated lactate concentration may result from shunting from pyruvate or

Pharmacodynamics

Alcohol produces injury to cells by dehydration and precipitation of the cytoplasm or protoplasm. This accounts for its bacteriocidal and antifungal action. When alcohol is injected in close proximity to nerve tissues, it produces neuritis and nerve degeneration (neurolysis). Ninety to 98% of ethanol that enters the body is completely oxidized. Ethanol is also used as a cosolvent to dissolve many insoluble drugs and to serve as a mild sedative in some medicinal formulations. Ethanol also binds to GABA, glycine, NMDA receptors and modulates their effects. Ethanol is also metabolised by the hepatic enzyme alcohol dehydrogenase.

Mechanism of action

Pyrimethamine inhibits the dihydrofolate reductase of plasmodia and thereby blocks the biosynthesis of purines and pyrimidines, which are essential for DNA synthesis and cell multiplication. This leads to failure of nuclear division at the time of schizont formation in erythrocytes and liver. Pyrimethamine is an antimalarial drug that has also been used successfully to treat autoimmune diseases such as lymphoproliferative syndrome. In this work, the effect of pyrimethamine (PYR) on the production of free radicals in malaria-infected mice was studied to better understand the drug's immunomodulatory properties. BALB/c and CBA/Ca mice were infected with Plasmodium yoelii 17XL. Seven days after infection, mice were treated with PYR or vehicle and sacrificed 24h later. Treatment with PYR increased superoxide dismutase and glutathione peroxidase activities in erythrocytes and the liver, augmented the levels of nitric oxide in the serum, and upregulated mRNA levels of superoxide dismutase, glutathione peroxidase, catalase, and iNOS in the spleen. In addition, PYR increased lipoperoxidation and protein carbonylation in infected mice. Our results indicate that P. yoelii 17XL reduces oxidative stress in infected cells, while PYR induces it, which is associated with increased parasite elimination. Thus, it is possible that oxidative stress generated by pyrimethamine is also involved in its immunomodulatory mechanism of action. Co-infection of human immunodeficiency virus (HIV) with malaria is one of the pandemic problems in Africa and parts of Asia. Here we investigated the impact of pyrimethamine (PYR) and two other clinical anti-malarial drugs (chloroquine [CQ] or artemisinin [ART]) on HIV-1 replication. Peripheral blood mononuclear cells (PBMCs) or MT-2 cells were infected with HIV(NL4.3) strain and treated with different concentrations of the anti-malarial drugs. HIV-1 replication was measured using p24 ELISA. We show that 10 uM CQ and ART inhibited HIV-1 replication by 76% and 60% in PBMCs, respectively, but not in MT-2 cells. In contrast, 10 uM PYR enhanced HIV-1 replication in MT-2 cells by >10-fold. A series of molecular mechanism studies revealed that PYR increased intracellular HIV gag proteins without affecting the promoter or the reverse transcriptase activity. The effect of PYR was independent of HTLV-1 produced by MT-2 cells. Of interest, PYR treatment led to S-phase accumulation and increased AZT and d4T antiviral activity by ~ 4-fold. Taken together, we show that PYR significantly enhances HIV-1 replication by affecting the cellular machinery. Our results could be relevant for the management of malaria and HIV particularly in regions where HIV-1 and malaria epidemics overlap. Autosomal dominant polycystic kidney disease (ADPKD) is a commonly inherited disorder mostly caused by mutations in PKD1, encoding polycystin-1 (PC1). The disease is characterized by development and growth of epithelium-lined cyst in both kidneys, often leading to renal failure. There is no specific treatment for this disease. Here, we report a sustained activation of the transcription factor signal transducer and activator of transcription 3 (STAT3) in ischemic injured and uninjured Pkd1 knockout polycystic kidneys and in human ADPKD kidneys. Through a chemical library screen, we identified the anti-parasitic compound pyrimethamine as an inhibitor of STAT3 function. Treatment with pyrimethamine decreases cell proliferation in human ADPKD cells and blocks renal cyst formation in an adult and a neonatal PKD mouse model. Moreover, we demonstrated that a specific STAT3 inhibitor, S3I-201, reduces cyst formation and growth in a neonatal PKD mouse model. Our results suggest that PC1 acts as a negative regulator of STAT3 and that blocking STAT3 signaling with pyrimethamine or similar drugs may be an attractive therapy for human ADPKD. The unresponsiveness of metastatic melanoma to conventional chemotherapeutic and biological agents is largely due to the de

Pharmacodynamics

Pyrimethamine is an antiparasitic compound commonly used as an adjunct in the treatment of uncomplicated, chloroquine resistant, P. falciparum malaria. Pyrimethamine is a folic acid antagonist and the rationale for its therapeutic action is based on the differential requirement between host and parasite for nucleic acid precursors involved in growth. This activity is highly selective against plasmodia and Toxoplasma gondii. Pyrimethamine possesses blood schizonticidal and some tissue schizonticidal activity against malaria parasites of humans. However, the 4-amino-quinoline compounds are more effective against the erythrocytic schizonts. It does not destroy gametocytes, but arrests sporogony in the mosquito. The action of pyrimethamine against Toxoplasma gondii is greatly enhanced when used in conjunction with sulfonamides.

Mechanism of action

The mechanism of plasmodicidal action of amodiaquine is not completely certain. Like other quinoline derivatives, it is thought to inhibit heme polymerase activity. This results in accumulation of free heme, which is toxic to the parasites. The drug binds the free heme preventing the parasite from converting it to a form less toxic. This drug-heme complex is toxic and disrupts membrane function. Amodiaquine is a Mannich base 4-aminoquinoline with a mode of action similar to that of chloroquine. It is effective against some chloroquine-resistant strains of P. falciparum, although there is cross-resistance. The 4-aminoquinoline derivatives appear to bind to nucleoproteins and interfere with protein synthesis in susceptible organisms; the drugs intercalate readily into double-stranded DNA and inhibit both DNA and RNA polymerase. In addition, the drugs apparently concentrate in parasite digestive vacuoles, increase the pH of the vacuoles, and interfere with the parasite's ability to metabolize and utilize erythrocyte hemoglobin. Plasmodial forms that do not have digestive vacuoles and do not utilize hemoglobin, such as exoerythrocytic forms, are not affected by /these medications/. The 4-aminoquinoline derivatives ... have anti-inflammatory activity; however, the mechanism(s) of action of the drugs in the treatment of rheumatoid arthritis and lupus erythematosus has not been determined. /4-aminoquinoline derivatives/ reportedly antagonizes histamine in vitro, has antiserotonin effects, and inhibits prostaglandin effects in mammalian cells presumably by inhibiting conversion of arachidonic acid to prostaglandin F2. The mode of action of amodiaquine has not yet been determined. 4-Aminoquinolines depress cardiac muscle, impair cardiac conductivity, and produce vasodilatation with resultant hypotension; they depress respiration and cause diplopia, dizziness and nausea.

Pharmacodynamics

Amodiaquine, a 4-aminoquinoline similar to chloroquine in structure and activity, has been used as both an antimalarial and an anti-inflammatory agent for more than 40 years. Amodiaquine is at least as effective as chloroquine, and is effective against some chloroquine-resistant strains, although resistance to amodiaquine has been reported. The mode of action of amodiaquine has not yet been determined. 4-Aminoquinolines depress cardiac muscle, impair cardiac conductivity, and produce vasodilatation with resultant hypotension. They depress respiration and cause diplopia, dizziness and nausea.

Mechanism of action

Positive allosteric modulators of the human sweet taste receptor ...developed as a new way of reducing dietary sugar intake .../can be used as/ ...valuable tool molecules to study the general mechanism of positive allosteric modulations of T1R taste receptors. Using chimeric receptors, mutagenesis, and molecular modeling, .../the study/ reveal how ...sweet enhancers follow a similar mechanism as the natural umami taste enhancer molecules. Whereas the sweeteners bind to the hinge region and induce the closure of the Venus flytrap domain of T1R2, the enhancers bind close to the opening and further stabilize the closed and active conformation of the receptor.

Mechanism of action

Sulfadoxine is a sulfa drug, often used in combination with pyrimethamine to treat malaria. This medicine may also be used to prevent malaria in people who are living in, or will be traveling to, an area where there is a chance of getting malaria. Sulfadoxine targets Plasmodium dihydropteroate synthase and dihydrofolate reductase. Sulfa drugs or Sulfonamides are antimetabolites. They compete with para-aminobenzoic acid (PABA) for incorporation into folic acid. The action of sulfonamides exploits the difference between mammal cells and other kinds of cells in their folic acid metabolism. All cells require folic acid for growth. Folic acid (as a vitamin) diffuses or is transported into human cells. However, folic acid cannot cross bacterial (and certain protozoan) cell walls by diffusion or active transport. For this reason bacteria must synthesize folic acid from p-aminobenzoic acid.

Pharmacodynamics

Sulfadoxine helps inhibit the enzyme dihydropteroate synthetase which is an enzyme necessary in the conversion of PABA to folic acid. As folic acid is vital to the synthesis, repair, and methylation of DNA which is vital to cell growth in Plasmodium falciparum. With this vital nutrient lacking, the parasite has difficulty in reproducing.