LEDOBOOK 10

Indications

• Low blood volume
• Hypovolemic shock
• Burns
• Cardiopulmonary bypass

Dosage

Children: Initially 10-20 mL per kilogram. Adjust according to the patient's condition and response, using 3.5-4% solution. Use under specialist supervision to mitigate the risk of fluid overload.

Adults: Dose according to requirements, typically administered intravenously. Consult product literature for specific dosing guidance.

Mechanism of action

Gelatin acts as a plasma expander by increasing the oncotic pressure in the vascular compartment, which helps to retain fluid within the bloodstream and restore circulating blood volume. This mechanism aids in maintaining blood pressure and improving tissue perfusion.

Pharmacodynamics

Gelatin solutions increase blood volume and improve hemodynamic stability in patients experiencing hypovolemic conditions. By drawing water into the vascular space, they help to counteract the effects of low blood volume, such as hypotension and compromised organ perfusion.

Pharmacokinetics

Gelatin is administered intravenously, and its effects can be observed relatively quickly. The half-life and the metabolic clearance depend on the formulation and concentration of the solution. Gelatin is gradually metabolized by macrophages and eliminated by the renal system. Close monitoring of fluid balance is essential, particularly in patients with cardiac or renal impairment.

Contra-indications

• Severe liver disease
• History of circulatory disease
• Severe cardiac disease

Adverse effects

• Fever
• Flushing
• Nausea
• Urticaria
• Rare or very rare shock

Interactions

• Calcium salts

Precautions

• Monitor cardiovascular and respiratory function
• Correct dehydration when administering
• Administer slowly to avoid rapid rise in blood pressure and cardiac failure
• Increased capillary permeability

Pregnancy

Consult product literature for specific guidance regarding use in pregnancy.

Breast-feeding

Consult product literature for specific guidance regarding use in breastfeeding.

Storage

Store at controlled room temperature, protect from light. Refer to product-specific storage instructions.

Formulations

• 5% solution for infusion
• 20% solution for infusion
• Concentrated solution (15-25% protein)
• Isotonic solution (3.5-5% protein)

Indications

• Newly diagnosed multiple myeloma in patients who have undergone autologous stem cell transplantation
• Newly diagnosed multiple myeloma in patients not eligible for transplant (in combination with melphalan and prednisone)

Mechanism of action

Lenalidomide alters cytokine production and regulates T cell co-stimulation, enhancing NK cell-mediated cytotoxicity. It directly inhibits the cullin ring E3 ubiquitin ligase complex by binding to cereblon, leading to the degradation of substrate proteins such as Ikaros (IKZF1) and Aiolos (IKZF3), which are essential for the differentiation and survival of malignant B cells. This degradation results in increased production of interleukin-2 (IL-2) and enhanced proliferation of NK and T cells, while also inhibiting pro-inflammatory cytokines like TNF-α, IL-1, IL-6, and IL-12.

Pharmacodynamics

Lenalidomide demonstrates antitumor effectiveness through its immunomodulatory, anti-inflammatory, and anti-angiogenic properties. It induces apoptosis and inhibits the proliferation of hematopoietic malignant cells, thereby delaying tumor growth. Lenalidomide enhances immune responses by stimulating T cell proliferation and NK cell activity, making it significantly more potent than thalidomide in these actions. It also limits tumor cell invasion and metastasis, contributing to its therapeutic efficacy in hematological cancers.

Pharmacokinetics

Lenalidomide is absorbed quickly after oral administration, with peak plasma concentrations occurring within 1-6 hours. It has a bioavailability of approximately 50%. The drug is primarily metabolized in the liver, with renal excretion of both unchanged drug and metabolites. The elimination half-life is approximately 3-4 hours in patients with normal renal function, and dosage adjustments are necessary in cases of renal impairment.

Contra-indications

• Active tuberculosis
• Pregnancy
• Breastfeeding

Adverse effects

• Leukopenia
• Thrombocytopenia
• Nephrotoxicity
• Stomatitis
• Mucositis
• Ulcer
• Eye disorders
• Erythema nodosum
• Confusion
• Anemia
• Fatigue
• Nausea
• Vomiting
• Diarrhea
• Hypertension
• Increased risk of infection

Interactions

• Combined hormonal contraceptives: increased risk of venous thromboembolism

Precautions

• Screen for active tuberculosis before treatment
• Monitor blood counts regularly
• Use with caution in patients with renal impairment
• Risk of embryo-fetal toxicity

Pregnancy

Avoid use during pregnancy due to potential risk to the fetus.

Breast-feeding

Avoid use while breastfeeding due to potential risks.

Storage

Store at room temperature, away from moisture and heat.

Formulations

• Capsules
• Powder for suspension for infusion

Dosage

Children: Refer to specific drug guidelines for dosing information.

Adults: Refer to specific drug guidelines for dosing information.

Mechanism of action

The body operates through various biological mechanisms that involve the interaction of hormones, neurotransmitters, and enzymes. These interactions regulate numerous physiological processes including homeostasis, immune response, and metabolic pathways.

Pharmacodynamics

Pharmacodynamics in the context of the body involves understanding how different substances affect bodily functions. This can include the action of drugs, nutrients, and other chemical agents, which can modify physiological responses through receptor binding, enzyme activity modulation, or ion channel regulation.

Pharmacokinetics

Pharmacokinetics refers to how substances are absorbed, distributed, metabolized, and excreted within the body. Factors such as blood flow, tissue permeability, and enzymatic activity play crucial roles in determining how long a drug remains active in the body, its efficacy, and potential for toxicity.

Pregnancy

Consult healthcare provider before use, as safety during pregnancy may vary based on specific conditions.

Breast-feeding

Consult healthcare provider before use, as safety during breastfeeding may vary based on specific conditions.

Storage

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

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

• Chronic hepatitis C virus infection
• Genotype 1 HCV infection

Dosage

Children: Refer to BNF for Children for specific dosing information tailored to paediatric patients.

Adults: Refer to BNF for specific dosing information based on the clinical scenario.

Mechanism of action

Paritaprevir inhibits the NS3/4A serine protease of the Hepatitis C Virus (HCV). This enzyme is responsible for cleaving the viral polypeptide into essential structural and nonstructural proteins necessary for the assembly of mature virus. By inhibiting NS3/4A, paritaprevir prevents viral replication and function.

Pharmacodynamics

At concentrations significantly above therapeutic levels, paritaprevir and its combination with ombitasvir do not prolong the QTc interval to a clinically relevant extent. This suggests a favorable safety profile concerning cardiac effects at therapeutic doses.

Pharmacokinetics

Paritaprevir is absorbed effectively after oral administration, with its pharmacokinetic profile characterized by a peak plasma concentration occurring within a few hours post-dose. It is extensively metabolized in the liver, primarily via CYP3A4, and is eliminated mainly through fecal excretion. The half-life of paritaprevir allows for once-daily dosing when used in combination therapies.

Pregnancy

The safety of paritaprevir in pregnancy has not been established. Use only if the potential benefit justifies the potential risk to the fetus.

Breast-feeding

It is unknown if paritaprevir is excreted in human milk. Caution is advised when administered to breastfeeding women.

Storage

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

Indications

• Wound healing
• Skin ulceration
• Burns
• Psoriasis
• Dermatitis

Dosage

Children: Refer to the BNF for Children for appropriate dosing information based on the child's age and condition.

Adults: Refer to the BNF for specific formulations and dosing guidelines, as dosages may vary based on the condition being treated and the formulation used.

Mechanism of action

While there is no well-controlled data to formally substantiate the method of action, ongoing studies suggest that allantoin may induce a histological wound healing profile in animal models, leading to improved reestablishment of normal skin. This includes increased vasodilation, inflammatory cell presence, angiogenesis, fibroblast proliferation, and collagen deposition in treated wounds compared to untreated ones.

Pharmacodynamics

There is limited controlled data regarding the pharmacodynamic properties of allantoin. However, studies indicate that allantoin may possess moisturizing and keratolytic effects, increasing the extracellular matrix's water content and enhancing the desquamation of dead skin cells. These activities can promote cell proliferation and facilitate wound healing.

Pharmacokinetics

Specific pharmacokinetic data for allantoin in humans is limited. However, it is known to be applied topically, which suggests local absorption at the site of application. Systemic absorption is considered minimal due to its low molecular weight and hydrophilicity.

Pregnancy

There is limited data on the safety of allantoin in pregnancy. It is advisable to consult a healthcare professional before use.

Breast-feeding

Allantoin is generally considered safe during breastfeeding, but caution is recommended. Consult a healthcare professional before use.

Storage

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

Formulations

• Topical cream
• Gel
• Ointment

Dosage

Children: Refer to specific pediatric dosing guidelines based on the identified drug, as 'hard' does not provide sufficient information.

Adults: Refer to specific drug information for dosing guidelines, as 'hard' does not specify a particular medication.

Mechanism of action

The mechanism of action for drugs termed 'hard' must be specified for accurate information, as this phrase does not designate a specific compound. Mechanisms may involve receptor interaction, enzyme inhibition, or modulation of biochemical pathways, depending on the drug in question. For example, opioid analgesics work primarily by binding to mu-opioid receptors in the central nervous system, leading to analgesic effects.

Pharmacodynamics

Pharmacodynamics refers to the effects of a drug on the body and its mechanisms of action. The pharmacodynamics of any drug classified as 'hard' would depend on its specific pharmacological profile, including its efficacy, potency, and the nature of its therapeutic effects. For instance, in the case of opioids, pharmacodynamic effects include pain relief, sedation, and potential respiratory depression.

Pharmacokinetics

Pharmacokinetics involves the absorption, distribution, metabolism, and excretion (ADME) of a drug. The pharmacokinetics of a substance termed 'hard' would vary significantly based on the specific drug. For many medications, absorption may occur via oral or parenteral routes, distribution may involve binding to plasma proteins, metabolism may occur in the liver, and excretion is typically renal. Each of these parameters is critical for understanding the drug's action and potential side effects.

Pregnancy

Consult a healthcare professional before use, as safety has not been established.

Breast-feeding

Consult a healthcare professional before use, as safety has not been established.

Storage

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

Dosage

Children: Refer to specific drug information for dosing guidelines.

Adults: Refer to specific drug information for dosing guidelines.

Pregnancy

Consult a healthcare provider for advice on use during pregnancy, as the safety of this medication may not be established.

Breast-feeding

Consult a healthcare provider before use while breastfeeding, as the drug may pass into breast milk.

Storage

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

Indications

• Lactose intolerance
• As a filler or excipient in pharmaceutical formulations

Dosage

Children: Refer to the BNF for Children for specific dosing information based on age and clinical context.

Adults: Refer to the BNF for specific dosing information based on clinical context.

Mechanism of action

Lactose is metabolized in the intestine by the enzyme lactase into its constituent monosaccharides, glucose and galactose. In individuals with lactase deficiency, unabsorbed lactose passes into the colon, where it is fermented by bacteria, leading to gas production and osmotic effects that contribute to diarrhea.

Pharmacodynamics

The pharmacodynamics of lactose are primarily related to its effects on gastrointestinal function. In healthy individuals, lactose is effectively broken down into glucose and galactose, which are absorbed and utilized for energy. In individuals with lactose intolerance, the unabsorbed lactose can cause osmotic diarrhea and colonic fermentation, leading to discomfort and symptoms associated with lactose intolerance.

Pharmacokinetics

Lactose is not absorbed in the gastrointestinal tract until it is hydrolyzed into glucose and galactose by lactase. The absorption of glucose and galactose occurs in the small intestine. The half-life is not applicable as lactose is not typically administered as a medication but is rather ingested as a natural component of food. Its metabolism primarily occurs in the intestine.

Adverse effects

• Bloating
• Diarrhea
• Abdominal pain
• Flatulence

Precautions

• Use with caution in patients with lactose intolerance.
• Consider potential for gastrointestinal upset in sensitive individuals.

Pregnancy

Lactose is generally considered safe for use during pregnancy. However, consult a healthcare professional for individual advice.

Breast-feeding

Lactose is safe to use while breastfeeding, as it is a natural sugar present in breast milk.

Storage

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

Formulations

• Powder
• Granules
• Tablets
• Syrup

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

• Drug delivery
• Controlled release of medications
• Protection of sensitive compounds

Dosage

Children: Dosage for paediatric patients is also dependent on the specific active ingredient within the shell. Refer to the BNF for Children for appropriate dosing information.

Adults: Dosage depends on the specific formulation and active ingredient contained within the shell. Refer to the specific drug monograph for dosing recommendations.

Mechanism of action

The mechanism of action of shells depends on the specific active ingredients they contain. Typically, the shell serves as a barrier that controls the release of the drug, enabling it to reach the desired site of action. This can involve various pathways, including diffusion through the shell material, enzymatic degradation, or dissolution in the gastrointestinal tract.

Pharmacodynamics

Pharmacodynamics of shell formulations is related to their ability to modulate the release profile of the encapsulated drug. This can result in altered onset of action, duration of effect, and therapeutic efficacy. The properties of the shell material can influence these dynamics, including factors such as thickness, permeability, and solubility in biological fluids.

Pharmacokinetics

Pharmacokinetics of shell-based drug formulations involves the absorption, distribution, metabolism, and excretion of the active ingredient following its release from the shell. The release rate can be affected by the shell's composition and the physicochemical properties of the drug. Typically, the drug is absorbed in the gastrointestinal tract, distributed throughout the body, metabolized primarily by the liver, and excreted via urine or feces.

Pregnancy

Not enough information available to assess safety in pregnancy. Consult healthcare provider.

Breast-feeding

Not enough information available to assess safety during breastfeeding. Consult healthcare provider.

Storage

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

Dosage

Children: Refer to the specific drug's prescribing information for paediatric dosing guidelines.

Adults: Refer to the specific drug's prescribing information for adult dosing guidelines.

Mechanism of action

The mechanism of action would depend on the specific drug referred to by 'size'. Generally, drugs exert their effects through interaction with biological targets such as receptors, enzymes, or ion channels, leading to a physiological response.

Pharmacodynamics

Pharmacodynamics refers to the effects of the drug on the body, including the relationship between drug concentration and effect. This can involve receptor binding, signal transduction, and the resulting biological effects. Specific dynamics would vary based on the drug in question.

Pharmacokinetics

Pharmacokinetics describes the absorption, distribution, metabolism, and excretion (ADME) of a drug. Factors such as bioavailability, volume of distribution, half-life, and clearance would vary significantly based on the specific drug being considered.

Pregnancy

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

Breast-feeding

Use with caution, as it is not known whether it is excreted in human milk.

Storage

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

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

Lenalidomide is a drug with multiple mechanisms of action. Lenalidomide exerts immunomodulating effects by altering cytokine production, regulating T cell co-stimulation, and enhancing the NK cell-mediated cytotoxicity. Lenalidomide directly inhibits the cullin ring E3 ubiquitin ligase complex: upon binding to cereblon, a substrate adaptor of the complex, lenalidomide modulates substrate specificity of the complex to recruit substrate proteins of the ligase, including Ikaros (IKZF1), Aiolos (IKZF3), and CK1α. These substrates are then tagged for ubiquitination and subsequent proteasomal degradation. IKZF1 and IKZF3 are B-cell transcription factors that are essential for B-cell differentiation and survival of malignant cells. IKZF3 also regulates the expression of interferon regulatory factor 4 (IRF4), which is a transcription factor that regulates the aberrant myeloma-specific gene. The immunomodulatory actions of lenalidomide can be partly explained by the degradation of IKZF3, since it is a repressor of the interleukin 2 gene (IL2): as lenalidomide decreases the level of IKZF3, the production of IL-2 increases, thereby increasing the proliferation of natural killer (NK), NKT cells, and CD4+ T cells. Lenalidomide inhibits the production of pro-inflammatory cytokines TNF-α, IL-1, IL-6, and IL-12, while elevating the production of anti-inflammatory cytokine IL-10. Lenalidomide acts as a T-cell co-stimulatory molecule that promotes CD3 T-cell proliferation and increases the production of IL-2 and IFN-γ in T lymphocytes, which enhances NK cell cytotoxicity and ADCC. It inhibits the expression and function of T-regulatory cells, which are often overabundant in some hematological malignancies. Lenalidomide directly exerts antitumour effects by inhibiting the proliferation and inducing apoptosis of tumour cells. Lenalidomide triggers the activation of pro-apoptotic caspase-8, enhances tumour cell sensitivity to FAS-induced apoptosis, and downregulates NF-κB, an anti-apoptotic protein. Independent of its immunomodulatory effects, lenalidomide mediates anti-angiogenic effects by inhibiting angiogenic growth factors released by tumour cells, such as vascular endothelial growth factor (VEGF), basic fibroblastic-growth factor (BFGF), and hepatocyte-growth factor. _In vitro_, lenalidomide inhibits cell adhesion molecules such as ICAM-1, LFA-1, β2 and β3 integrins, as well as gap-junction function, thereby preventing metastasis of malignant cells. Multiple myeloma is a B-cell malignancy characterized by an excess of monotypic plasma cells in the bone marrow. The molecular mechanisms that are involved in disease progression depend on the interaction between the multiple myeloma cells and the bone microenvironment. Because these mechanisms have been well characterized, it is possible to develop regimens that are more specific to pathways involved in the pathogenesis of multiple myeloma than is typical for conventional chemotherapy in disease management. Thalidomide and immunomodulatory drugs (IMiDs) have now been shown to block several pathways important for disease progression in multiple myeloma. First established as agents with antiangiogenic properties, thalidomide and IMiDs inhibit the production of interleukin (IL)-6, which is a growth factor for the proliferation of myeloma cells. In addition, they activate apoptotic pathways through caspase 8-mediated cell death. At the mitochondrial level, they are responsible for c-jun terminal kinase (JNK)-dependent release of cytochrome-c and Smac into the cytosol of cells, where they regulate the activity of molecules that affect apoptosis. By activating T cells to produce IL-2, thalidomide and IMiDs alter natural killer (NK) cell numbers and function, thus augmenting the activity of NK-dependent cytotoxicity. Data delineating these events have been derived from experiments done in resistant and sensitive multiple myeloma cell lines. Although thalidomide and IMiDs demonstrate similar biologic

Pharmacodynamics

In hematological malignancies, the immune system is deregulated in the form of altered cytokine networks in the tumour microenvironment, defective T cell regulation of host-tumour immune interactions, and diminished NK cell activity. Lenalidomide is an immunomodulatory agent with antineoplastic, antiangiogenic, and anti-inflammatory properties. Lenalidomide exerts direct cytotoxicity by increasing apoptosis and inhibiting the proliferation of hematopoietic malignant cells. It delays tumour growth in nonclinical hematopoietic tumour models _in vivo_, including multiple myeloma. Lenalidomide also works to limit the invasion or metastasis of tumour cells and inhibits angiogenesis. Lenalidomide also mediates indirect antitumour effects via its immunomodulatory actions: it inhibits the production of pro-inflammatory cytokines, which are implicated in various hematologic malignancies. Lenalidomide enhances the host immunity by stimulating T cell proliferation and enhancing the activity of natural killer (NK) cells. Lenalidomide is about 100–1000 times more potent in stimulating T cell proliferation than [thalidomide]. _In vitro_, it enhances antibody-dependent cell-mediated cytotoxicity (ADCC), which is even more pronounced when used in combination with rituximab. Due to its anti-inflammatory properties, lenalidomide has been investigated in the context of inflammatory and autoimmune diseases, such as amyotrophic lateral sclerosis.

Mechanism of action

Paritaprevir is a potent inhibitor of the NS3/4A serine protease of Hepatitis C Virus (HCV). Following viral replication of HCV genetic material and translation into a single polypeptide, Nonstructural Protein 3 (NS3) and its activating cofactor Nonstructural Protein 4A (NS4A) are responsible for cleaving it into the following structural and nonstructural proteins required for assembly into mature virus: NS3, NS4A, NS4B, NS5A, and NS5B. By inhibiting viral protease NS3/4A, paritaprevir therefore prevents viral replication and function.

Pharmacodynamics

At concentrations approximately 6 and 1.8 times the therapeutic concentrations of paritaprevir and ombitasvir, the combination did not prolong QTc to any clinically relevant extent.

Mechanism of action

There is no well controlled data that can formally substantiate the method of action. However, ongoing studies suggest that there may exist a histological wound healing profile induced by allantoin in rats that leads to the amelioration and fastening of the reestablishment of normal skin. This facilitation of wound healing is supported by observations that wounds inflicted to rat subjects to which topical allantoin preparations were applied histologically demonstrated increased vasodilation, presence of inflammatory exudates, number of inflammatory cells, angiogenesis, fibroblast proliferation, and increased collagen deposition when compared to rat subjects with wounds that did not receive any allantoin administration.

Pharmacodynamics

There is no well controlled and appropriate data that can formally substantiate the pharmacodynamic properties of allantoin. Nevertheless, ongoing studies suggest that allantoin possesses moisturizing and keratolytic effects, as well as abilities to increase the water content of the extracellular matrix and enhance the desquamation of upper layers of dead skin cells, all of which are activities that can promote cell proliferation and facilitate wound healing.