FAROPLAV 75

Indications

• Prevention of atherothrombotic events in patients with acute coronary syndrome
• Secondary prevention of ischaemic stroke
• Prevention of atherothrombotic events in peripheral arterial disease

Mechanism of action

Clopidogrel is activated through a two-step metabolic process to form an active thiol-containing metabolite. This metabolite irreversibly binds to the P2Y12 ADP receptors on platelets, preventing ADP from activating the GPIIb/IIIa complex, which is crucial for platelet aggregation. As a result, clopidogrel inhibits platelet aggregation for the lifespan of the platelets (approximately 7 to 10 days). The inhibition of the P2Y12 receptor reduces platelet activation and aggregation not just from ADP, but also from other agonists.

Pharmacodynamics

Clopidogrel is a prodrug that serves as a potent antiplatelet agent, effectively reducing the risk of myocardial infarction and stroke. Its pharmacological effects are long-lasting, allowing for once-daily dosing. Clopidogrel exhibits a broad therapeutic window, and its dosage ranges from 75 mg to 300 mg per day, depending on the clinical scenario. Its action helps maintain blood flow and prevent occlusive vascular events.

Pharmacokinetics

Clopidogrel is well absorbed in the gastrointestinal tract, with peak plasma concentrations occurring within 1 to 2 hours after oral administration. It undergoes extensive hepatic metabolism, primarily through CYP450 enzymes, which convert it into its active form. The elimination half-life of clopidogrel is approximately 6 hours, but the antiplatelet effect lasts much longer due to the irreversible nature of its action on platelets. It is primarily excreted through urine, with a majority of the dose eliminated as inactive metabolites.

Contra-indications

• Active bleeding

Adverse effects

• Confusion
• Fever
• Gynaecomastia
• Hallucination
• Hepatic disorders
• Hypotension
• Myalgia
• Neutropenia
• Severe cutaneous adverse reactions (SCARs)
• Stomatitis
• Taste altered
• Ulcerative colitis
• Vasculitis
• Vertigo
• Wound haemorrhage

Interactions

• Voriconazole + clopidogrel: Severe (decreases efficacy)
• HIV protease inhibitors + clopidogrel: Severe (decreases efficacy)
• Moclobemide + clopidogrel: Severe (decreases efficacy)
• Ritonavir + clopidogrel: Severe (decreases efficacy)
• Clopidogrel + pioglitazone: Moderate (increases exposure)
• Clopidogrel + treprostinil: Moderate (increases exposure)
• Clopidogrel + apalutamide: Unknown (increases exposure)
• Clopidogrel + enzalutamide: Unknown (increases exposure)
• Fluconazole + clopidogrel: Unknown (decreases efficacy)
• Clopidogrel + anti-androgens: Unknown (increases exposure)

Precautions

• Caution with history of hypersensitivity reactions to thienopyridines
• Caution in moderate hepatic impairment
• Caution in renal impairment
• Discontinue 7 days before elective surgery if antiplatelet effect not desirable
• Patients at risk of increased bleeding from trauma, surgery, or other pathological conditions

Pregnancy

Manufacturer advises avoid-no information available.

Breast-feeding

Manufacturer advises avoid.

Storage

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

Formulations

• Clopidogrel 75 mg tablet
• Clopidogrel 300 mg tablet
• Clopidogrel oral suspension

Mechanism of action

The acetyl group can participate in a variety of biochemical reactions, most notably in the acetylation of proteins, where it may modulate the activity of enzymes and receptors. This modification can impact gene expression, signal transduction, and metabolic processes.

Pharmacodynamics

Acetylation is a key process in pharmacodynamics, affecting the pharmacological activity of numerous drugs and endogenous compounds. By adding an acetyl group, the solubility, stability, and bioavailability of compounds can be altered, influencing their therapeutic effects and duration of action.

Pharmacokinetics

The pharmacokinetics of acetylated compounds can vary widely depending on the specific drug involved. Generally, acetylation can enhance drug metabolism and excretion, impacting the half-life and overall clearance from the body. Variability in acetylation can also lead to differences in drug efficacy and toxicity among individuals.

Indications

• Acid-base imbalance
• Buffering agent in biochemical reactions
• Industrial applications

Mechanism of action

Bisulfate acts as a buffering agent, helping to maintain the pH of biological fluids. It can donate protons (H+) in solution, contributing to acid-base homeostasis. This property is essential in various metabolic pathways, particularly in the regulation of cellular functions and enzyme activities.

Pharmacodynamics

The pharmacodynamics of bisulfate involve its ability to interact with other ions and compounds in the body, influencing acid-base balance. By acting as a proton donor, bisulfate contributes to the overall acidity or alkalinity of the environment, which can affect cellular metabolism and function. It plays a significant role in respiratory and metabolic acidosis and alkalosis.

Pharmacokinetics

The pharmacokinetics of bisulfate are not extensively detailed in traditional pharmacological literature. However, it is known that bisulfate can be rapidly absorbed and utilized in metabolic processes. Its effects are largely dependent on the physiological conditions of the body, including the presence of other electrolytes and the overall acid-base status.

Pregnancy

There are no specific studies on the use of bisulfate in pregnancy. Caution is advised when administering to pregnant women.

Breast-feeding

It is not known whether bisulfate is excreted in human milk. Caution is advised when administering to breastfeeding women.

Storage

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

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

Dosage

Children: Refer to specific clinical guidelines for dosing in children, as no standard paediatric dosage is specified in the provided resources.

Adults: Refer to specific clinical guidelines for dosing, as no standard adult dosage is specified in the provided resources.

Mechanism of action

Ethylene glycol toxicity results from its metabolism to glycolic acid and other toxic metabolites. Glycolate accumulates in the body and is eliminated more slowly than ethylene glycol itself. The renal excretion of both compounds plays a crucial role in their elimination, accounting for a significant portion of the administered dose.

Pharmacodynamics

The pharmacodynamics of glycolate are closely tied to its role as a metabolite of ethylene glycol. Its accumulation can lead to metabolic acidosis, although minimal clinical effects have been observed at low doses. The relationship between glycolate and ethylene glycol indicates that glycolate may contribute to the overall toxic effects of ethylene glycol ingestion.

Pharmacokinetics

The pharmacokinetics of glycolate indicate that it reaches peak plasma levels between 4-6 hours after the administration of ethylene glycol. The elimination half-life of ethylene glycol is approximately 1.7 hours in rats and 3.4 hours in dogs. Glycolate is predominantly eliminated through renal excretion, with about 5% of the dose being excreted unchanged.

Pregnancy

There is limited data on the safety of glycolate in pregnancy. Caution is advised.

Breast-feeding

Data on the excretion of glycolate in human milk is not available. Caution is advised.

Storage

Store at room temperature, away from light and moisture.

Indications

• Dry eye syndrome
• Ocular lubrication
• Topical drug delivery
• Thickening agent in pharmaceutical formulations
• Emulsifying agent

Dosage

Children: Refer to specific product guidelines for dosing, as HPMC is used in various formulations and concentrations.

Adults: Refer to specific product guidelines for dosing, as HPMC is used in various formulations and concentrations.

Mechanism of action

HPMC works by forming a gel-like structure when hydrated, which can retain moisture and provide lubrication. In ocular formulations, it increases the viscosity of the solution, prolonging the contact time with the eye surface, thereby enhancing the therapeutic effect. It also acts as a stabilizer in emulsions and suspensions, preventing the separation of ingredients.

Pharmacodynamics

The pharmacodynamic properties of HPMC are primarily associated with its ability to modify viscosity and create a protective barrier when applied topically. In ophthalmic formulations, it helps to maintain tear film stability and reduces evaporation, which is beneficial in treating dry eye conditions. Additionally, it facilitates the sustained release of active pharmaceutical ingredients from formulations.

Pharmacokinetics

HPMC is not significantly absorbed systemically when applied topically or used in ocular formulations. Its metabolism involves hydrolysis and microbial degradation in the gastrointestinal tract when ingested. The elimination of HPMC from the body is primarily via feces, as it is not actively absorbed into the bloodstream.

Pregnancy

HPMC (Hydroxypropyl Methylcellulose) is generally considered safe for use during pregnancy, but it is always best to consult a healthcare provider.

Breast-feeding

HPMC is unlikely to be harmful during breastfeeding, but nursing mothers should consult a healthcare provider before use.

Storage

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

Formulations

• Eye drops
• Ophthalmic gel
• Oral capsules
• Oral tablets
• Topical preparations

Indications

• Methionine deficiency
• Hepatotoxicity prevention
• Cholesterol management

Mechanism of action

The mechanism of the possible anti-hepatotoxic activity of L-methionine is not entirely clear. It is thought that metabolism of high doses of acetaminophen in the liver leads to decreased levels of hepatic glutathione and increased oxidative stress. L-methionine serves as a precursor to L-cysteine, which has antioxidant properties and is a precursor to glutathione. The antioxidant activity of L-methionine and its metabolites likely contribute to its potential anti-hepatotoxic effects. Methionine also exhibits free-radical scavenging activity and chelating ability due to its sulfur content.

Pharmacodynamics

L-Methionine functions as a primary supplier of sulfur, which is essential for preventing hair, skin, and nail disorders. It aids in lowering cholesterol levels by enhancing the liver's production of lecithin, reducing liver fat, and protecting kidney function. Methionine acts as a natural chelating agent for heavy metals and helps regulate ammonia formation, contributing to ammonia-free urine and reduced bladder irritation. Furthermore, it influences hair follicles and promotes hair growth, in addition to its potential protective effects against hepatotoxins like acetaminophen.

Pharmacokinetics

Methionine is absorbed from the gastrointestinal tract and is distributed throughout the body, where it is utilized in protein synthesis and converted into other metabolites, such as S-adenosylmethionine and L-cysteine. The metabolism of methionine involves several pathways, including transsulfuration to cysteine and incorporation into proteins. The renal clearance of methionine is significant, as it is involved in the regulation of nitrogen balance and the formation of ammonia.

Adverse effects

• Nausea
• Vomiting
• Abdominal pain
• Allergic reactions

Precautions

• Use with caution in patients with liver disease
• Monitor for allergic reactions in sensitive individuals

Pregnancy

There is insufficient evidence to determine the safety of methionine during pregnancy. Consult a healthcare provider before use.

Breast-feeding

It is not known whether methionine is excreted in human milk. Caution is advised when administering to breastfeeding women.

Storage

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

Formulations

• Oral tablets
• Powder for oral solution

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

• 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

Indications

• Prevention of poliomyelitis infection
• Vaccination in children and high-risk populations

Dosage

Children: Refer to the BNF for Children for specific dosages and recommendations for vaccination schedules.

Adults: Refer to specific vaccination guidelines for adults, as dosages may vary based on risk factors and prior vaccination history.

Mechanism of action

Poliovirus enters the body through the oral route, replicating in the oropharynx and gastrointestinal tract before spreading to the central nervous system via the bloodstream. Once inside the CNS, the virus selectively infects motor neurons in the anterior horn of the spinal cord, leading to cell lysis and resulting in muscle weakness or paralysis. The immune response to the virus contributes to inflammation and further neuronal damage.

Pharmacodynamics

The poliovirus's pathogenicity is primarily due to its ability to evade the host's immune response and its selective neurotropism. The destruction of motor neurons leads to flaccid paralysis, with recovery possible in some cases as the motor neurons may regenerate. The severity of the disease correlates with the extent of neuronal involvement, which can vary widely among individuals.

Pharmacokinetics

Poliovirus is an RNA virus that does not undergo traditional pharmacokinetic processes as it is not treated with drugs. Instead, the prevention of polio relies on vaccination strategies. The inactivated poliovirus vaccine (IPV) and the oral poliovirus vaccine (OPV) are used to induce immunity. After administration, the vaccines promote the development of antibodies against the virus without causing disease.

Contra-indications

• Hypersensitivity to the vaccine component
• Severe immunodeficiency
• Acute febrile illness

Adverse effects

• Pain at injection site
• Fever
• Fatigue
• Headache
• Nausea
• Allergic reactions

Interactions

• Immunosuppressive therapies may reduce vaccine efficacy
• Concomitant administration with other vaccines may affect immune response

Precautions

• Use with caution in individuals with moderate to severe acute illness
• Consider history of allergic reactions
• Monitor for signs of anaphylaxis after administration

Pregnancy

Poliomyelitis vaccination is generally considered safe during pregnancy, but consult a healthcare professional.

Breast-feeding

The vaccine is considered safe for breastfeeding mothers.

Storage

Store at 2 to 8 degrees Celsius. Do not freeze. Protect from light.

Formulations

• Inactivated poliovirus vaccine (IPV)
• Oral poliovirus vaccine (OPV)

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

• 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

• Used as an excipient in drug formulations
• Pleurodesis for the management of recurrent pleural effusions

Dosage

Children: Refer to specific guidelines for paediatric use, as dosing may differ based on age and clinical condition.

Adults: Refer to specific guidelines for the appropriate dosage in pleurodesis and other applications, as it may vary based on clinical context.

Mechanism of action

Talc exhibits very good absorptive properties, allowing it to absorb moisture and other substances effectively. This characteristic is particularly useful in pharmaceutical formulations, where it may enhance the stability and texture of the drug product.

Pharmacodynamics

Talc's primary pharmacodynamic effect is its ability to act as an inert filler and bulking agent in pharmaceutical preparations. It does not have any intrinsic pharmacological activity but serves to improve the physical properties of formulations, such as flowability and compressibility.

Pharmacokinetics

Talc is not absorbed systemically when used as an excipient or in medical procedures. Its effects are local, and it remains in the site of application, where it functions primarily as a mechanical agent. The pharmacokinetics of talc in the context of its use in pleurodesis involves its ability to promote adhesion of the pleural surfaces, thereby preventing fluid accumulation.

Pregnancy

Talc is classified as a substance with minimal systemic absorption, but safety during pregnancy has not been well established. Consult relevant guidelines.

Breast-feeding

Talc is not expected to be absorbed in significant amounts; however, caution is advised and consult guidelines.

Storage

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

Indications

• Influenza
• HIV/AIDS
• Hepatitis B and C
• Herpes simplex virus infections
• Cytomegalovirus infections
• COVID-19
• Respiratory syncytial virus infections

Dosage

Children: Refer to specific antiviral agents for dosing guidance.

Adults: Refer to specific antiviral agents for dosing guidance.

Mechanism of action

Viruses infect host cells by attaching to specific receptors on the cell surface. Once inside, they hijack the host cell's machinery to replicate their genetic material and produce viral proteins. New viral particles are assembled and released from the host cell, often destroying the cell in the process. The specific mechanism can vary depending on the virus type, including integration into the host genome in retroviruses or utilizing specific pathways for replication.

Pharmacodynamics

The pharmacodynamics of antiviral agents depend on the specific virus and the mechanism of action. Antiviral drugs may inhibit viral entry into host cells, block viral replication, or prevent the assembly of new virions. The effectiveness of antiviral therapy often relates to the stage of viral replication and the immune response of the host.

Pharmacokinetics

Pharmacokinetics of antiviral drugs varies widely based on the specific medication used. Generally, antiviral agents are absorbed through the gastrointestinal tract and distributed throughout the body. They may undergo hepatic metabolism and are often excreted through the kidneys. The half-life of these drugs can range from a few hours to several days, influencing dosing schedules.

Mechanism of action

Clopidogrel is activated via a 2 steps reaction to an active thiol-containing metabolite. This active form is a platelet inhibitor that irreversibly binds to P2Y₁₂ ADP receptors on platelets. This binding prevents ADP binding to P2Y₁₂ receptors, activation of the glycoprotein GPIIb/IIIa complex, and platelet aggregation. Clopidogrel must be metabolized by CYP450 enzymes to produce the active metabolite that inhibits platelet aggregation. The active metabolite of clopidogrel selectively inhibits the binding of adenosine diphosphate (ADP) to its platelet P2Y12 receptor and the subsequent ADP-mediated activation of the glycoprotein GPIIb/IIIa complex, thereby inhibiting platelet aggregation. This action is irreversible. Consequently, platelets exposed to clopidogrel's active metabolite are affected for the remainder of their lifespan (about 7 to 10 days). Platelet aggregation induced by agonists other than ADP is also inhibited by blocking the amplification of platelet activation by released ADP. The P2Y12 receptor plays a crucial role in the regulation of platelet activation by several agonists, which is irreversibly antagonized by the active metabolite of clopidogrel, a widely used anti-thrombotic drug. In this study, we investigated whether reduction of platelet reactivity leads to reduced inflammatory responses using a rat model of erosive arthritis. We evaluated the effect of clopidogrel on inflammation in Lewis rats in a peptidoglycan polysaccharide (PG-PS)-induced arthritis model with four groups of rats: 1) untreated, 2) clopidogrel-treated, 3) PG-PS-induced, and 4) PG-PS-induced and clopidogrel-treated. There were significant differences between the PG-PS+clopidogrel group when compared to the PG-PS group including: increased joint diameter and clinical manifestations of inflammation, elevated plasma levels of pro-inflammatory cytokines (IL-1 beta, interferon (IFN) gamma, and IL-6), an elevated neutrophil blood count and an increased circulating platelet count. Plasma levels of IL-10 were significantly lower in the PG-PS+clopidogrel group compared to the PG-PS group. Plasma levels of platelet factor 4 (PF4) were elevated in both the PG-PS and the PG-PS+clopidogrel groups, however PF4 levels showed no difference upon clopidogrel treatment, suggesting that the pro- inflammatory effect of clopidogrel may be due to its action on cells other than platelets. Histology indicated an increase in leukocyte infiltration at the inflammatory area of the joint, increased pannus formation, blood vessel proliferation, subsynovial fibrosis and cartilage erosion upon treatment with clopidogrel in PG-PS-induced arthritis animals. In summary, animals treated with clopidogrel showed a pro-inflammatory effect in the PG-PS-induced arthritis animal model, which might not be mediated by platelets.

Pharmacodynamics

Clopidogrel is a prodrug of a platelet inhibitor used to reduce the risk of myocardial infarction and stroke. It has a long duration of action as it is taken once daily and a large therapeutic window as it is given in doses of 75-300mg daily.

Mechanism of action

Ethylene glycol toxicity results from its metabolism to glycolic acid and other toxic metabolites. The accumulation of glycolate and the elimination kinetics of ethylene glycol and its metabolites are not well understood, so studies with male Sprague-Dawley rats and mixed breed dogs have been carried out. Ethylene glycol was administered by gavage to rats and dogs which were placed in metabolic cages for urine and blood sample collection at timed intervals. The peak plasma level of ethylene glycol occurred at 2 hr after dosing and that of glycolate between 4-6 hr. The rate of ethylene glycol elimination was somewhat faster in rats with a half-life of 1.7 hr compared to 3.4 hr in dogs. The maximum plasma level of glycolate was greater in rats although the pattern of accumulation was similar to that in dogs. Glycolate disappeared from the plasma at the same time as ethylene glycol, suggesting a slower rate of elimination of the metabolite than that of ethylene glycol. Renal excretion of ethylene glycol was an important route for its elimination accounting for 20-30% of the dose. Renal excretion of glycolate represented about 5% of the dose. Ethylene glycol induced an immediate, but short lived diuresis compared to that in control rats. Minimal clinical effects (mild acidosis with no sedation) were noted at these doses of ethylene glycol (1-2 g/kg) in both rats and dogs. The results indicate that the toxicokinetics of ethylene glycol and glycolate were similar in both species. The effect of 0.35 to 0.8 mmol/kg glycolic acid and 1.0 to 4.4 mmol/kg sodium glycolate on cyclopropane-epinephrine induced cardiac arrhythmias was examined using dogs. Doses of 0.35 to 0.5 mmol/kg glycolic acid increased the duration of arrhythmias in the 13 dogs tested, whereas doses >0.5 mmol/kg decreased or totally eliminated the arrhythmias in each of 11 dogs. Depression was observed for many of the dogs at higher doses. Sodium glycolate was much less effective in decreasing the arrhythmias, with 3 mmol/kg being required and its action being transient.

Mechanism of action

The mechanism of the possible anti-hepatotoxic activity of L-methionine is not entirely clear. It is thought that metabolism of high doses of acetaminophen in the liver lead to decreased levels of hepatic glutathione and increased oxidative stress. L-methionine is a precursor to L-cysteine. L-cysteine itself may have antioxidant activity. L-cysteine is also a precursor to the antioxidant glutathione. Antioxidant activity of L-methionine and metabolites of L-methionine appear to account for its possible anti-hepatotoxic activity. Recent research suggests that methionine itself has free-radical scavenging activity by virtue of its sulfur, as well as its chelating ability. Amino acids are selected for protein synthesis by binding with transfer RNA (tRNA) in the cell cytoplasm. The information on the amino acid sequence of each individual protein is contained in the sequence of nucleotides in the messenger RNA (mRNA) molecules, which are synthesized in the nucleus from regions of DNA by the process of transcription. The mRNA molecules then interact with various tRNA molecules attached to specific amino acids in the cytoplasm to synthesize the specific protein by linking together individual amino acids; this process, known as translation, is regulated by amino acids (e.g., leucine), and hormones. Which specific proteins are expressed in any particular cell and the relative rates at which the different cellular proteins are synthesized, are determined by the relative abundances of the different mRNAs and the availability of specific tRNA-amino acid combinations, and hence by the rate of transcription and the stability of the messages. From a nutritional and metabolic point of view, it is important to recognize that protein synthesis is a continuing process that takes place in most cells of the body. In a steady state, when neither net growth nor protein loss is occurring, protein synthesis is balanced by an equal amount of protein degradation. The major consequence of inadequate protein intakes, or diets low or lacking in specific indispensable amino acids relative to other amino acids (often termed limiting amino acids), is a shift in this balance so that rates of synthesis of some body proteins decrease while protein degradation continues, thus providing an endogenous source of those amino acids most in need. /Protein synthesis/ The mechanism of intracellular protein degradation, by which protein is hydrolyzed to free amino acids, is more complex and is not as well characterized at the mechanistic level as that of synthesis. A wide variety of different enzymes that are capable of splitting peptide bonds are present in cells. However, the bulk of cellular proteolysis seems to be shared between two multienzyme systems: the lysosomal and proteasomal systems. The lysosome is a membrane-enclosed vesicle inside the cell that contains a variety of proteolytic enzymes and operates mostly at acid pH. Volumes of the cytoplasm are engulfed (autophagy) and are then subjected to the action of the protease enzymes at high concentration. This system is thought to be relatively unselective in most cases, although it can also degrade specific intracellular proteins. The system is highly regulated by hormones such as insulin and glucocorticoids, and by amino acids. The second system is the ATP-dependent ubiquitin-proteasome system, which is present in the cytoplasm. The first step is to join molecules of ubiquitin, a basic 76-amino acid peptide, to lysine residues in the target protein. Several enzymes are involved in this process, which selectively targets proteins for degradation by a second component, the proteasome. /Protein degradation/ Methionine dependence, the inability of cells to grow when the amino acid methionine is replaced in culture medium by its metabolic precursor homocysteine, is characteristic of many cancer cell lines and some tumors in situ. Most cell lines proliferate normally under these conditions. The methionine dependent t

Pharmacodynamics

L-Methionine is a principle supplier of sulfur which prevents disorders of the hair, skin and nails; helps lower cholesterol levels by increasing the liver's production of lecithin; reduces liver fat and protects the kidneys; a natural chelating agent for heavy metals; regulates the formation of ammonia and creates ammonia-free urine which reduces bladder irritation; influences hair follicles and promotes hair growth. L-methionine may protect against the toxic effects of hepatotoxins, such as acetaminophen. Methionine may have antioxidant activity.

Mechanism of action

It has very good absorptive properties.