أسئلة السادسة فارما PPPM (قبل التعديل)

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Questions and Answers

Which of the following medications is represented by the term '‫وديكسا‬'?

  • Dexamethasone (correct)
  • kni
  • Omeprazole
  • Ciprofloxacin

If a patient requires ciprofloxacin, which term would correctly identify the medication?

  • Omeprazole
  • ‫أويم‬
  • ‫كني‬ (correct)
  • Dexamethasone

A pharmacist receives a prescription for '‫أويم‬'. Which medication should they dispense?

  • kni
  • Omeprazole (correct)
  • Dexamethasone
  • Ciprofloxacin

Which medication name is likely to be used to treat bacterial infections?

<p>kni (B)</p> Signup and view all the answers

A doctor wants to prescribe a medication to reduce inflammation. Which of the following options should the doctor consider?

<p>Dexamethasone (C)</p> Signup and view all the answers

Which of the following best describes the interaction between phenytoin and cyclosporine A?

<p>Phenytoin induces the metabolism of cyclosporine A, potentially leading to decreased cyclosporine A levels and graft rejection. (C)</p> Signup and view all the answers

Erythromycin increases the risk of theophylline toxicity by which mechanism?

<p>Inhibiting the metabolism of theophylline, leading to elevated serum levels. (C)</p> Signup and view all the answers

A patient taking theophylline develops arrhythmia after being prescribed erythromycin. Which of the following is the MOST likely cause?

<p>Erythromycin inhibits the metabolism of theophylline, resulting in increased theophylline levels and subsequent arrhythmia. (B)</p> Signup and view all the answers

A patient on cyclosporine A begins taking phenytoin. What adjustments might be necessary to maintain therapeutic cyclosporine A levels?

<p>Increase the dose of cyclosporine A. (A)</p> Signup and view all the answers

Which of the following drug-drug interactions could potentially lead to subtherapeutic medication levels?

<p>Phenytoin accelerating the metabolism of cyclosporine A. (C)</p> Signup and view all the answers

In a clinical setting, why is it essential to understand the specific mechanism of action for drugs like chloramphenicol and macrolides?

<p>To anticipate potential drug interactions and resistance mechanisms. (D)</p> Signup and view all the answers

A patient is prescribed a medication that inhibits protein synthesis in bacteria. If the medication non-selectively binds to both prokaryotic and eukaryotic ribosomes, what is the most likely consequence?

<p>The medication will likely cause significant toxicity to the patient's cells. (B)</p> Signup and view all the answers

Which of the following statements best describes the primary difference in the mechanism of action between chloramphenicol and macrolides?

<p>Chloramphenicol primarily inhibits peptidyl transferase, while macrolides block the translocation step. (A)</p> Signup and view all the answers

A new antibiotic is discovered that also targets the 50S ribosomal subunit. Initial studies show that it prevents the formation of the initiation complex. Which stage of protein synthesis is directly inhibited by this new antibiotic?

<p>Initiation (B)</p> Signup and view all the answers

Suppose a bacterium develops resistance to both chloramphenicol and erythromycin (a macrolide). What is the most likely mechanism that could confer cross-resistance to these two drugs?

<p>Alteration of the 50S ribosomal subunit structure. (C)</p> Signup and view all the answers

Which category of enzymes is primarily responsible for breaking down proteins into smaller peptides or amino acids?

<p>Peptidases (C)</p> Signup and view all the answers

What class of enzymes is known for its broad substrate specificity and ability to hydrolyze a wide range of ester bonds?

<p>Nonspecific esterases (A)</p> Signup and view all the answers

Which enzyme is responsible for the breakdown of acetylcholine, a neurotransmitter, in the nervous system?

<p>Cholinesterase (B)</p> Signup and view all the answers

Which enzyme plays a primary role in the degradation of the peptide hormone insulin?

<p>Insulinase (B)</p> Signup and view all the answers

A researcher is studying the metabolism of a novel peptide and identifies an enzyme that cleaves the peptide into smaller fragments. Based on the content, which type of enzyme is most likely involved in this process?

<p>Peptidase (A)</p> Signup and view all the answers

Predict the impact of administering Rifampin together with Ketoconazole, considering their potential interaction through hepatic enzyme systems?

<p>Rifampin will significantly decrease the plasma concentration of Ketoconazole, potentially reducing its effectiveness. (A)</p> Signup and view all the answers

A patient is prescribed Rifampin for tuberculosis. What advice should the healthcare provider give regarding potential interactions with other medications?

<p>The patient should inform the healthcare provider of all medications they are taking, including over-the-counter drugs, due to Rifampin's broad interaction potential. (D)</p> Signup and view all the answers

A patient taking ketoconazole reports decreased drug effectiveness after starting rifampin. What is the most likely reason for this?

<p>Rifampin induces hepatic enzymes, leading to increased metabolism of ketoconazole. (A)</p> Signup and view all the answers

If a patient requires both rifampin and ketoconazole, what strategy might a healthcare provider employ to mitigate potential drug interactions?

<p>Choose an alternative antifungal agent, that does not have significant interactions with rifampin. (A)</p> Signup and view all the answers

How does Rifampin's mechanism of action contribute to its potential for drug interactions?

<p>Rifampin induces cytochrome P450 enzymes, altering the metabolism of other drugs. (D)</p> Signup and view all the answers

Why is benzylpenicillin typically administered via injection rather than orally?

<p>Benzylpenicillin is unstable in the acidic environment of the stomach. (A)</p> Signup and view all the answers

Why is insulin typically administered via injection rather than orally?

<p>Insulin is a peptide hormone that is degraded by digestive enzymes in the gastrointestinal tract. (D)</p> Signup and view all the answers

What is the primary reason L-dopa is often administered with carbidopa?

<p>Carbidopa inhibits the metabolism of L-dopa in the peripheral tissues, increasing its availability to the brain. (D)</p> Signup and view all the answers

What is the most likely consequence of administering benzylpenicillin orally?

<p>Reduced drug bioavailability due to destruction in the stomach. (C)</p> Signup and view all the answers

A patient taking L-dopa experiences nausea and vomiting. How does the understanding of L-dopa metabolism inform the strategies to manage these side effects?

<p>Co-administering carbidopa to inhibit peripheral metabolism of L-dopa. (B)</p> Signup and view all the answers

Which term accurately defines the process of chemical alteration of drugs within the body?

<p>Metabolism (D)</p> Signup and view all the answers

In the context of pharmacology, what is the Arabic term '‫التكسري‬' most accurately translated to?

<p>Metabolism (D)</p> Signup and view all the answers

If a drug's structure is altered within the body, which pharmacological process is directly responsible for this change?

<p>Metabolism (D)</p> Signup and view all the answers

Considering the breakdown of a drug into its metabolites, which process is fundamentally involved?

<p>Metabolism (A)</p> Signup and view all the answers

Which concept is most closely associated with 'chemical alteration of drugs in the body'?

<p>Drug metabolism (D)</p> Signup and view all the answers

Which conjugation reaction is MOST likely to affect the metabolism of steroid hormones?

<p>Sulfation by sulfotransferase (A)</p> Signup and view all the answers

A patient exhibits significantly altered drug response due to a genetic defect affecting acetylation. Which drug's metabolism would be MOST affected?

<p>Isoniazid (A)</p> Signup and view all the answers

A drug's half-life is significantly prolonged in patients with compromised hepatic function. Which conjugation reaction would MOST likely be impaired, leading to this prolonged half-life?

<p>Glucuronidation (D)</p> Signup and view all the answers

If a patient has a genetic deficiency in catechol-O-methyltransferase (COMT), the metabolism of which substance would be MOST directly affected?

<p>Noradrenaline (D)</p> Signup and view all the answers

A researcher is investigating a new drug that undergoes extensive sulfation. Which enzyme would be MOST crucial to study to understand the drug's metabolism?

<p>Sulfotransferase (D)</p> Signup and view all the answers

A drug is metabolized into an active metabolite. How does this impact the original drug's effects?

<p>It can either prolong or alter the drug's effects due to the metabolite's own pharmacological activity. (A)</p> Signup and view all the answers

If a drug's metabolism results in an inactive metabolite, what is the expected consequence?

<p>Termination of the drug’s effects, reducing its concentration in the body. (A)</p> Signup and view all the answers

Codeine is metabolized into morphine. What is the pharmacological significance of this conversion?

<p>The metabolism prolongs and enhances analgesia due to morphine's activity. (D)</p> Signup and view all the answers

A new drug is discovered that, upon metabolism, produces both an active and an inactive metabolite. What is the most complex consideration when determining appropriate dosing?

<p>Balancing the therapeutic benefits contributed by the active metabolite with the removal of active drug. (D)</p> Signup and view all the answers

A patient with impaired liver function is prescribed a prodrug that is metabolized into an active compound. How should the prescribing physician adjust the dosage?

<p>Switch to a different medication that does not require metabolic activation. (C)</p> Signup and view all the answers

Which of the following conditions warrants the use of Lincosamides (‫)لينكو‬?

<p>Severe bacterial infections in patients with penicillin allergies. (B)</p> Signup and view all the answers

How do smoking (‫ )بيدخنو‬and alcohol (‫ )ويسكرو‬consumption primarily impact the effectiveness of many medications?

<p>By altering liver enzyme activity, leading to either increased drug metabolism or reduced drug efficacy. (C)</p> Signup and view all the answers

What is a significant pharmacological consideration when administering Isoniazid (‫)أيزو‬?

<p>Isoniazid's metabolism varies genetically, affecting drug efficacy and the risk of adverse effects. (B)</p> Signup and view all the answers

Which of the following is the primary mechanism of action for Azole antifungals?

<p>Inhibition of ergosterol synthesis, disrupting fungal cell membrane integrity. (C)</p> Signup and view all the answers

A patient is prescribed both Isoniazid (‫)أيزو‬ and Rifampin for the treatment of tuberculosis. What is the primary concern regarding this drug combination?

<p>Elevated likelihood of hepatotoxicity stemming from their combined effects on liver metabolism. (C)</p> Signup and view all the answers

A patient taking oral contraceptives is prescribed rifampin for tuberculosis. What is the most critical piece of information to convey regarding the interaction between these medications?

<p>Rifampin may decrease the effectiveness of oral contraceptives, necessitating the use of a non-hormonal backup method. (A)</p> Signup and view all the answers

Why is the interaction between rifampin and estrogen-containing oral contraceptives clinically significant?

<p>Rifampin induces hepatic enzymes, accelerating the metabolism of estrogen and potentially reducing the efficacy of the contraceptive. (C)</p> Signup and view all the answers

A patient on oral contraceptives requires antibiotic treatment. Which antibiotic is LEAST likely to interact with their contraceptive, based on the information provided?

<p>Amoxicillin (D)</p> Signup and view all the answers

A 28-year-old woman on oral contraceptives is diagnosed with latent tuberculosis and prescribed rifampin. Considering the drug interaction, which of the following management strategies would be the MOST appropriate?

<p>Advise the patient to discontinue oral contraceptives during rifampin treatment and switch to a barrier method. (B)</p> Signup and view all the answers

A patient on combined oral contraceptives presents to the clinic with a new diagnosis of tuberculosis requiring rifampin. She expresses concern about contraceptive failure. Which course of action is MOST appropriate?

<p>Counsel the patient to use a non-hormonal method of contraception consistently throughout rifampin therapy and for one month after discontinuing rifampin. (D)</p> Signup and view all the answers

In cases where a drug undergoes partial first-pass metabolism, how should the oral dosage be adjusted compared to the intravenous dosage to achieve a similar therapeutic effect?

<p>The oral dosage should be significantly higher than the IV dosage to compensate for the fraction metabolized. (B)</p> Signup and view all the answers

How does proteolytic degradation affect the bioavailability of peptide drugs like insulin when administered orally, and what implications does this have for drug delivery?

<p>Proteolytic degradation reduces bioavailability, necessitating alternative routes of administration such as injection. (C)</p> Signup and view all the answers

A novel peptide-based therapeutic is developed, showing promise in initial trials. However, oral administration results in negligible plasma concentrations. What is the MOST probable reason for this?

<p>The peptide is extensively metabolized by proteolytic enzymes in the gastrointestinal tract. (C)</p> Signup and view all the answers

A patient is switched from intravenous propranolol to oral propranolol. Given that propranolol undergoes significant first-pass metabolism, what adjustment to the dosage should be expected to maintain a similar therapeutic effect?

<p>The oral dose should be significantly higher than the intravenous dose to account for first-pass metabolism. (B)</p> Signup and view all the answers

A research team is formulating a new oral drug. To optimize its bioavailability, they need to consider the impact of first-pass metabolism. Which strategy would be MOST effective in minimizing the first-pass effect?

<p>Developing a formulation that enhances lymphatic absorption, avoiding hepatic portal circulation. (A)</p> Signup and view all the answers

Flashcards

Warfarin Accumulation Consequence

Warfarin buildup can lead to increased risk of bleeding.

Phenytoin & Cyclosporine A Interaction

Phenytoin speeds up cyclosporine A metabolism, reducing its effectiveness and potentially causing graft rejection.

Erythromycin & Theophylline Interaction

Erythromycin inhibits the metabolism of theophylline, potentially leading to theophylline toxicity and arrhythmias.

Drug Metabolism

The process by which the body breaks down and eliminates drugs, influenced by enzyme activity.

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Arrhythmia

An irregular heartbeat, often a sign of drug toxicity or adverse effects.

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Dexamethasone

A corticosteroid medication used to reduce inflammation and suppress the immune system.

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Ciprofloxacin

Also known as 'Cipro', it's a fluoroquinolone antibiotic used to treat bacterial infections.

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Omeprazole

A proton pump inhibitor (PPI) that reduces stomach acid production.

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Medications ending in 'sone'

Medication ending in 'sone' is likely what type of medication?

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Medications ending in 'prazole'

Medication ending in 'prazole' is likely what type of medication?

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Rifampin

An antibiotic medication used to treat several types of bacterial infections, including tuberculosis.

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Ketoconazole

An antifungal medication used to treat fungal infections.

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Chloramphenicol

Chloramphenicol is an antibiotic.

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Macrolides

Macrolides are a class of antibiotics.

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Erythromycin

Erythromycin is a type of macrolide antibiotic.

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Macrolides Mechanism

Macrolides work by targeting bacterial ribosomes, inhibiting protein synthesis.

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Macrolides use

Macrolides such as erythromycin are commonly used to treat respiratory and skin infections.

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Nonspecific Esterases

Enzymes that hydrolyze a broad range of ester substrates, without strict specificity for a particular ester bond.

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Acetylcholine Metabolism

The breakdown of acetylcholine, a neurotransmitter, by the enzyme cholinesterase.

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Peptidases

A type of enzyme that breaks down peptides by hydrolyzing the peptide bonds between amino acids.

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Insulin Metabolism

The degradation of insulin, a peptide hormone, by the enzyme insulinase.

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Insulinase

Enzyme responsible for insulin metabolism.

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Benzylpenicillin Stability

Gastric acid breaks down and inactivates benzylpenicillin, reducing its effectiveness if taken orally.

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Oral Insulin Ineffectiveness

Digestive enzymes in the gastrointestinal tract can degrade peptide hormones like insulin when administered orally.

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L-dopa Metabolism in Gut

COMT in the intestinal lining metabolizes L-dopa, reducing the amount available for absorption.

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Gastric Acid Drug Degradation

Gastric acidity can degrade certain orally administered drugs.

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Enzymatic Hormone Degradation

Enzymes in the intestines degrade hormones such as insulin

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Drug Metabolism Definition

Process of chemical alteration of drugs within the body.

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Metabolism: Chemical Alteration

Metabolism involves breaking down drugs into different chemical components.

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Drug Metabolism: Process

The process of drug metabolism.

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What happens in drug metabolism?

Drug metabolism is the chemical alteration of drugs in the body.

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Lincosamides

Lincosamides are a class of antibiotics.

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Isoniazid

Isoniazid is a medication used to treat tuberculosis (TB).

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Azoles

A class of antifungal medications with a characteristic chemical structure.

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Smoking & Alcohol

Concurrent use of alcohol and smoking. May refer to harmful interactions with medications.

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Termination of Drug Effect

The end of a drug's effects in the body, often due to metabolism or excretion.

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Inactive Metabolite

When a drug is converted into a form that has little to no pharmacological activity.

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Active Metabolite

A drug that has been transformed by the body into a form that still exerts a pharmacological effect.

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Prolongation of Drug Effect

Conversion of a drug into a form whose effects last longer than the original drug.

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Codeine to Morphine

A drug (codeine) is changed by the body into another active drug (morphine).

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Methylation

Adding a methyl group to a substance.

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COMT (Catechol-O-Methyltransferase)

An enzyme that catalyzes the transfer of methyl groups.

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Acetylation

Adding an acetyl group (acetic acid) to a substance during a reaction.

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Sulfation

Adding a sulfate group to a substance, catalyzed by sulfotransferase.

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Sulfotransferases

Enzymes that add a sulfate group to molecules, typically steroids.

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Antibiotics & Estrogen Pill Interaction

A debated drug interaction primarily proven for rifampin and rifabutin.

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Enzyme Induction

The process where certain antibiotics increase the activity of enzymes that metabolize estrogen.

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Rifampin & Estrogen Interaction

Rifampin increases the metabolism of estrogen, reducing its effectiveness.

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Rifabutin

An antibiotic derivative similar in action to rifampin regarding drug interactions.

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Drug Interaction Consequence

Drug interactions can reduce the effectiveness of other medications in the body.

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Proteolytic Insulin Degradation

Abnormal breakdown of insulin by proteolytic enzymes.

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First-Pass Effect

The phenomenon where a drug's concentration is significantly reduced before it reaches systemic circulation due to liver enzymes.

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Dose Adjustment for First-Pass

Increasing the dose of an oral drug to compensate for reduced bioavailability due to the first-pass effect.

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Propranolol First-Pass Example

Propranolol, taken orally, is metabolized significantly by the liver, decreasing its concentration in the blood.

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Bioavailability

The fraction of the drug that makes it to the systemic circulation.

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Study Notes

  • Metabolism, or biotransformation, refers to the process of chemical alteration of drugs in the body.

Site of Metabolism

  • Liver: Primary site of drug metabolism.
  • Other organs involved: kidney, lungs, and the gastrointestinal tract.

Effect of Enzymes on Drugs

  • Active Drug converted to Inactive Metabolite: Most common outcome, leads to termination of the drug effect.
  • Active Drug converted to Active Metabolite: Leads to prolongation of the drug effect; for example, codeine converts to morphine.
  • Inactive Drug (Pro-Drug) converted to Active Metabolite: L-dopa is converted to dopamine, and enalapril becomes enalaprilat.
  • Non-Toxic Drug converted to Toxic Metabolite: This occurs when paracetamol is converted to N-acetyl benzo-quinone.
  • Metabolism aims to convert lipid-soluble drugs to water-soluble metabolites.
  • This conversion facilitates drug excretion in body water, including urine, bile, milk, and sweat.
  • It also decreases tissue penetration and potential re-absorption due to the increased water solubility.

Biochemical Reactions in Drug Metabolism

  • Phase 1 Reactions: Oxidation, reduction, and hydrolysis.
  • Phase 2 Reactions: Conjugation.
  • Drugs converted into water-soluble compounds via Phase 1 reactions may not need to undergo Phase 2 metabolism.

Phase 1 Reactions - Oxidation

  • Oxidation: The addition of O2, or the removal of H+ from the drug.

Microsomal Oxidation:

  • Utilizes oxidizing enzymes located in the microsomes of many organs, especially the liver.
  • Microsomes are sub-cellular membranous vesicles found in the smooth endoplasmic reticulum of cells.
  • Cytochrome P450 enzyme (Cp450 or CYP450) is the primary enzyme in the microsomal enzyme system.
  • CP450 family consists of numerous iso-enzymes, formed of hemoproteins, that catalyze oxidation-reduction reactions, acting as mixed function oxidases.

Microsomal Liver Enzyme Inducers and Inhibitors

  • Microsomal Enzyme Induction:
    • Increases the rate of metabolism for some drugs, resulting in decreased serum levels and therapeutic failure.
    • For acetaminophen, induced metabolism can lead to increased levels of toxic metabolites.
    • An increased dose may be required for a drug affected by metabolism.
    • Examples of inducers: Rifampicin (can accelerate the metabolism of contraceptive pills, and may cause failure of contraception) and Phenytoin (accelerates metabolism of cyclosporine A, potentially causing graft rejection).

Microsomal Enzyme Inhibition:

  • Decreases the rate of metabolism for some drugs, leading to increased serum levels and toxicity.
  • An opposite or decreased dose of the drug may be required.
  • Examples of inhibitors: Ciprofloxacin (inhibits warfarin metabolism, leading to accumulation and bleeding) and Erythromycin (inhibits theophylline metabolism, resulting in theophylline toxicity and arrhythmia).

Examples of Enzyme Inducers

  • Oxcarbazepine
  • Carbamazepine
  • Dexamethasone
  • Omeprazole
  • Phenytoin
  • Phenobarbitone
  • Smoking & alcohol
  • Rifampin
  • St. John's Wort

Examples of Enzyme Inhibitors

  • Cimetidine
  • Allopurinol
  • Quinolones (ciprofloxacin)
  • Chloramphenicol
  • Macrolides (erythro & clarithro)
  • Lincosamides
  • Isoniazide
  • Azoles (ketoconazole)
  • Interferon
  • Ritonavir
  • Grapefruit juice

Non-Microsomal Oxidation

  • Done By: Soluble enzymes in cytoplasm or mitochondria.
  • Xanthine Oxidase: Converts xanthine into uric acid.
  • Monoamine oxidase (MAO): Oxidizes catecholamines and serotonin.

Reduction Reaction

  • Less common compared to oxidation.
  • Types:
    • Microsomal: Nitroreductase (chloramphenicol).
    • Non-microsomal: Carbonyl reductase (naloxone).

Hydrolysis Reactions

  • Mainly non-microsomal, occurring in plasma, tissues, & body fluids.
  • Involves Non-specific esterases, such as Cholinesterase, involved in acetylcholine metabolism.
  • Also involves Peptidases: Insulin metabolism by insulinase.
  • If a drug is initially water-soluble, it does not need to undergo metabolism and is excreted unchanged.

Phase 2 Reactions (Conjugation) Definition

  • Involves the coupling of a drug or its metabolite to an endogenous substrate, usually glucuronic acid, to form a water-soluble conjugate that can be easily excreted in urine or bile

Types of Endogenous Substrates and Conjugation Reactions

  • Glucuronide Conjugation (Microsomal)
    • Most common conjugation reaction.
    • Involves the conjugation of activated glucuronic acid to drugs or metabolites.
    • Glucuronide conjugates are inactive and rapidly excreted in urine or bile.
    • Glucuronide conjugates secreted in bile are hydrolyzed by intestinal bacteria, which can free the drug to be reabsorbed (enterohepatic circulation), increasing the duration of drug action e.g. estrogen pills.
  • Other Conjugation Reactions (Non-Microsomal)
    • Glutathione conjugation: Uses glutathione (for acetaminophen, ethacrynic acid).
  • Glycine conjugation: Uses glycine (for salicylic acid).
  • Methylation: Uses a methyl group (COMT for noradrenaline).
  • Acetylation: Uses acetic acid (for isoniazid, salicylic acid).
  • Sulfation: Uses sulfotransferase (for steroid hormones).

Breakthrough Pregnancy

  • Contraceptive pills contain estrogen, which undergoes metabolism through glucuronide conjugation before excretion via bile conjugate.
  • Intestinal bacteria can hydrolyze the estrogen conjugate in the gut, freeing estrogen for reabsorption, lengthening its duration of action.
  • Antibiotics can disrupt this process by killing the intestinal bacteria
  • Estrogen from contraceptive pills may lose its prolonged action, thus increasing the chances of pregnancy.
  • The drug interaction between antibiotics and estrogen pills is debatable and only proven for rifampin.

First-Pass Metabolism (Pre-Systemic Elimination) Definition

  • Occurs when drugs are metabolized at the site of administration before reaching systemic circulation.

First-Pass Metabolism (Pre-Systemic Elimination) Examples

  • Oral Route:
    • Gut First-Pass Metabolism: Gastric acidity destroys benzyl penicillin, digestive enzymes, and hormones such as insulin degrade COMT found in intestinal mucosa metabolize L-dopa.
    • Hepatic First-Pass Metabolism: drugs degraded by the liver include Morphine & H2-blockers, Beta Blockers, Nitrates
  • Lung Absorption: Some metabolism can occur following inhalation.
  • SC After Topical Skin Application: Insulin can be degraded by proteolytic enzymes.

How to Avoid First-Pass Metabolism

  • Increase drug dose if the first-pass effect is partial: For example, 5mg Propranolol IV is equivalent to 100mg orally administered.
  • Utilize other drug routes if the first pass effect is comprehensive: These options are Sublingual, inhalation, or intravenous.
  • In cases of acute angina, sublingual nitroglycerin is preferred over oral

Factors Affecting Drug Metabolism

  • Genetic Factors: Acetylation status (fast or slow metabolizers).
  • Malnutrition: Decreased availability of vitamins & amino acids (needed for metabolism).
  • Age (Extremes): Metabolism may be decreased in the elderly and in children aged < 6 months.
  • Liver Disease & Liver Cell Failure (LCF): Impaired hepatic enzyme function and decreased amino acid availability.
  • Hepatic Enzyme Inducers or Inhibitors:
    • Reduced drug metabolism leads to decreased clearance and longer t1/2 , requiring a decrease drug dose.
    • Increased drug metabolism leads to increased clearance and shorter t1/2, increasing the needed drug dose.

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