Antibiotics Pharmacology Quiz
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Questions and Answers

What is the mechanism of action of clindamycin?

  • Disruption of bacterial DNA replication
  • Inhibition of cell wall synthesis
  • Activation of bacterial autolysins
  • Inhibition of protein synthesis (correct)

    • Which type of bacteria is clindamycin effective against?

  • Both Gram-positive and Gram-negative
  • Gram-positive, including MRSA and streptococcus (correct)
  • Anaerobic bacteria only
  • Gram-negative, including E. coli and Pseudomonas

    • How is clindamycin primarily eliminated from the body?

  • Renal excretion
  • Excretion into bile and urine (correct)
  • Exhalation through the lungs
  • Metabolism by the liver

    • What is the main modification in fluoroquinolones compared to the 1st generation quinolones?

    <p>Fluorination of the quinolone nucleus</p> Signup and view all the answers

    Why are fluoroquinolones considered 2nd line options for various indications?

    <p>Due to resistance to Gram-negative and Gram-positive organisms</p> Signup and view all the answers

    Which type of bacteria are fluoroquinolones effective against?

    <p>Both Gram-negative and Gram-positive</p> Signup and view all the answers

    What is the mechanism of action of Amphotericin B?

    <p>It binds to ergosterol, forming pores, disrupting membrane function, leading to cell death</p> Signup and view all the answers

    What is the drug of choice for several life-threatening mycoses?

    <p>Amphotericin B</p> Signup and view all the answers

    How is oral amphotericin B primarily used?

    <p>For local GI tract treatment</p> Signup and view all the answers

    What is the primary route of excretion for amphotericin B?

    <p>Urine</p> Signup and view all the answers

    What is the resistance factor associated with amphotericin B?

    <p>Ergosterol content and structure</p> Signup and view all the answers

    What is the primary method of administration for amphotericin B?

    <p>Parenterally (slow IV infusion)</p> Signup and view all the answers

    What is the treatment duration for multidrug-resistant TB (MDR-TB)?

    <p>At least 2 years</p> Signup and view all the answers

    How is isoniazid activated in the body?

    <p>By mycobacterial catalaseperoxidase (KatG)</p> Signup and view all the answers

    What is the mechanism of action of rifampin?

    <p>Blocks RNA transcription</p> Signup and view all the answers

    Which drug is specific for mycobacteria and inhibits arabinosyl transferases required for cell wall synthesis?

    <p>Ethambutol</p> Signup and view all the answers

    What is a potential adverse effect of isoniazid?

    <p>Peripheral neuropathy</p> Signup and view all the answers

    Why may rifabutin be used as an alternative to rifampin?

    <p>To reduce the risk of rare hepatitis and death</p> Signup and view all the answers

    What is the primary route of excretion for trimethoprim?

    <p>Renal excretion</p> Signup and view all the answers

    What is a potential adverse effect of methenamine?

    <p>GI distress</p> Signup and view all the answers

    What is the mechanism of action of nitrofurantoin?

    <p>Inhibiting DNA and RNA synthesis</p> Signup and view all the answers

    What is the mechanism of action of trimethoprim?

    <p>Inhibitor of bacterial dihydrofolate reductase</p> Signup and view all the answers

    What can cause resistance to trimethoprim?

    <p>Altered dihydrofolate reductase</p> Signup and view all the answers

    What is the first-line therapy for uncomplicated cystitis?

    <p>Nitrofurantoin</p> Signup and view all the answers

    What is the mechanism of action of quinolones and fluoroquinolones?

    <p>Inhibit bacterial DNA gyrase and topoisomerase IV</p> Signup and view all the answers

    Which infections are quinolones and fluoroquinolones effective against?

    <p>Gram-positive and Gram-negative organisms, anaerobic infections</p> Signup and view all the answers

    How can resistance to quinolones and fluoroquinolones occur?

    <p>Altered target binding, decreased accumulation, enzymatic degradation</p> Signup and view all the answers

    How are quinolones and fluoroquinolones absorbed in the body?

    <p>Well absorbed orally, with high bioavailability</p> Signup and view all the answers

    What are the adverse reactions to quinolones and fluoroquinolones?

    <p>Gastrointestinal and central nervous system effects, tendinitis, tendon rupture, drug interactions</p> Signup and view all the answers

    What is the mechanism of action of sulfonamides?

    <p>Inhibit de novo synthesis of folate</p> Signup and view all the answers

    What is the primary mechanism of resistance associated with fluoroquinolones?

    <p>Altered DNA gyrase or topoisomerase IV enzymes</p> Signup and view all the answers

    Which type of bacteria are fluoroquinolones primarily effective against?

    <p>Gram-positive and gram-negative</p> Signup and view all the answers

    What is the primary route of excretion for clindamycin?

    <p>Bile and urine</p> Signup and view all the answers

    How are fluoroquinolones primarily eliminated from the body?

    <p>Renal excretion</p> Signup and view all the answers

    Which type of infections are clindamycin primarily used to treat?

    <p>Gram-positive, such as MRSA, streptococcus, and anaerobic bacteria</p> Signup and view all the answers

    What is the primary method of administration for fluoroquinolones?

    <p>Oral and IV</p> Signup and view all the answers

    What is a potential adverse effect of quinolones and fluoroquinolones?

    <p>Photosensitivity</p> Signup and view all the answers

    How are quinolones and fluoroquinolones primarily excreted from the body?

    <p>Renally</p> Signup and view all the answers

    What is the mechanism of resistance to sulfonamides?

    <p>Altered cellular permeability</p> Signup and view all the answers

    Which adverse effect is associated with sulfonamides?

    <p>Thrombocytopenia</p> Signup and view all the answers

    How are sulfonamides primarily metabolized in the body?

    <p>Conjugation</p> Signup and view all the answers

    What is a potential adverse effect of folate antagonists like sulfonamides?

    <p>Megaloblastic anemia</p> Signup and view all the answers

    What is the primary method of administration for amphotericin B?

    <p>Intravenous infusion</p> Signup and view all the answers

    What is the mechanism of action of amphotericin B?

    <p>Disruption of membrane function</p> Signup and view all the answers

    What is the resistance factor associated with amphotericin B?

    <p>Ergosterol content and structure</p> Signup and view all the answers

    How is amphotericin B primarily excreted from the body?

    <p>Through urine</p> Signup and view all the answers

    In addition to intravenous infusion, in what other form can amphotericin B be administered?

    <p>Intrathecal administration</p> Signup and view all the answers

    What is the drug of choice for several life-threatening mycoses?

    <p>Amphotericin B</p> Signup and view all the answers

    What is the treatment duration for latent tuberculosis infection (LTBI) with isoniazid monotherapy?

    <p>9 months</p> Signup and view all the answers

    Which enzyme is required for the activation of isoniazid in the body?

    <p>KatG</p> Signup and view all the answers

    What is the primary mechanism of action of rifampin against mycobacteria?

    <p>Inhibition of RNA transcription</p> Signup and view all the answers

    Which drug disrupts mycobacterial cell membrane metabolism and transport functions?

    <p>Pyrazinamide</p> Signup and view all the answers

    What is the primary target of ethambutol in mycobacteria?

    <p>Cell wall synthesis</p> Signup and view all the answers

    What is the reason for the increased incidence of mycoses?

    <p>Immune suppression</p> Signup and view all the answers

    What is the mechanism of action of methenamine?

    <p>It is hydrolyzed to ammonia and formaldehyde in acidic urine, denaturing bacterial cell components</p> Signup and view all the answers

    What is the first-line therapy for uncomplicated cystitis?

    <p>Nitrofurantoin</p> Signup and view all the answers

    What is the resistance factor associated with trimethoprim?

    <p>Altered dihydrofolate reductase</p> Signup and view all the answers

    What is the primary route of excretion for methenamine?

    <p>Renal excretion</p> Signup and view all the answers

    What are the adverse effects of nitrofurantoin?

    <p>GI distress and contraindicated in renal insufficiency</p> Signup and view all the answers

    What is the spectrum of activity for methenamine?

    <p>Effective against E. coli, Enterococcus spp., Staphylococcus spp., and some activity against Proteus and Pseudomonas aeruginosa</p> Signup and view all the answers

    Which of the following is true about clindamycin?

    <p>It is primarily excreted through the bile</p> Signup and view all the answers

    What is the primary mechanism of resistance associated with fluoroquinolones?

    <p>Mutations in DNA gyrase and topoisomerase IV</p> Signup and view all the answers

    What is the primary route of excretion for fluoroquinolones?

    <p>Urine</p> Signup and view all the answers

    Which enzyme is required for the activation of isoniazid in the body?

    <p>KatG</p> Signup and view all the answers

    What type of bacteria are fluoroquinolones primarily effective against?

    <p>Gram-negative</p> Signup and view all the answers

    What is the reason for the increased frequency of C. difficile associated with fluoroquinolones?

    <p>Disruption of normal gut flora</p> Signup and view all the answers

    What is the primary route of excretion for amphotericin B?

    <p>Renal excretion</p> Signup and view all the answers

    What is the mechanism of action of amphotericin B?

    <p>Fungicidal - binds to ergosterol, forming pores and disrupting membrane function</p> Signup and view all the answers

    What is the drug of choice for several life-threatening mycoses?

    <p>Amphotericin B</p> Signup and view all the answers

    What is the resistance factor associated with amphotericin B?

    <p>Ergosterol content and structure</p> Signup and view all the answers

    In addition to intravenous infusion, in what other form can amphotericin B be administered?

    <p>Intrathecal administration</p> Signup and view all the answers

    How is oral amphotericin B primarily used?

    <p>For local GI tract treatment</p> Signup and view all the answers

    Which of the following is a potential adverse effect of quinolones and fluoroquinolones?

    <p>Gastrointestinal and central nervous system effects</p> Signup and view all the answers

    What is the primary mechanism of resistance associated with quinolones and fluoroquinolones?

    <p>Altered target binding</p> Signup and view all the answers

    How are sulfonamides primarily metabolized in the body?

    <p>Acetylation and conjugation in the liver</p> Signup and view all the answers

    What is the spectrum of activity for sulfonamides?

    <p>Bacteriostatic against Gram-positive and Gram-negative organisms</p> Signup and view all the answers

    How are quinolones and fluoroquinolones excreted from the body?

    <p>Renally</p> Signup and view all the answers

    What is the primary route of excretion for sulfonamides?

    <p>Renally</p> Signup and view all the answers

    Which antimycobacterial drug disrupts mycobacterial cell membrane metabolism and transport functions, is active at low pH, and used for a short period in combination with other drugs?

    <p>Pyrazinamide</p> Signup and view all the answers

    What is the primary target of ethambutol in mycobacteria?

    <p>Cell wall synthesis</p> Signup and view all the answers

    Which antimycobacterial drug is a prodrug activated by mycobacterial catalaseperoxidase (KatG) and targets enzymes required for mycolic acid synthesis?

    <p>Isoniazid</p> Signup and view all the answers

    What is the treatment duration for latent tuberculosis infection (LTBI) with isoniazid monotherapy?

    <p>9 months</p> Signup and view all the answers

    Which antimycobacterial drug blocks RNA transcription and is bactericidal against intracellular and extracellular mycobacteria?

    <p>Rifampin</p> Signup and view all the answers

    What is the adverse effect associated with rifampin?

    <p>Hepatitis</p> Signup and view all the answers

    Which drug can be used alone for UTIs and bacterial prostatitis?

    <p>Nitrofurantoin</p> Signup and view all the answers

    What is the primary route of excretion for trimethoprim?

    <p>Renal excretion</p> Signup and view all the answers

    What is the mechanism of action of methenamine?

    <p>Denaturing bacterial cell components</p> Signup and view all the answers

    Which drug is contraindicated in renal insufficiency?

    <p>Methenamine</p> Signup and view all the answers

    What is the first-line therapy for uncomplicated cystitis?

    <p>Nitrofurantoin</p> Signup and view all the answers

    What is the mechanism of action of trimethoprim?

    <p>Inhibition of folic acid formation</p> Signup and view all the answers

    Clindamycin is a chlorine-substituted derivative of lincomycin.

    <p>True</p> Signup and view all the answers

    The mechanism of action of clindamycin is the same as macrolides.

    <p>True</p> Signup and view all the answers

    Clindamycin is primarily effective against Gram-positive bacteria such as MRSA, streptococcus, and anaerobic bacteria.

    <p>True</p> Signup and view all the answers

    Clindamycin distributes well to all body fluids, including CSF.

    <p>False</p> Signup and view all the answers

    C. difficile is susceptible to clindamycin treatment.

    <p>False</p> Signup and view all the answers

    Fluoroquinolones are considered 2nd line options for various indications due to resistance to Gram-negative and Gram-positive organisms.

    <p>True</p> Signup and view all the answers

    Amphotericin B is a water-soluble drug for the treatment of mycotic infections

    <p>False</p> Signup and view all the answers

    Amphotericin B binds to ergosterol, disrupting membrane function and leading to cell death

    <p>True</p> Signup and view all the answers

    Amphotericin B is primarily excreted through the kidneys

    <p>True</p> Signup and view all the answers

    Amphotericin B is the drug of choice for several life-threatening mycoses

    <p>True</p> Signup and view all the answers

    Amphotericin B is primarily administered orally for subcutaneous and systemic mycotic infections

    <p>False</p> Signup and view all the answers

    Amphotericin B has a wide antifungal spectrum, including Candida albicans and Aspergillus

    <p>True</p> Signup and view all the answers

    Quinolones and fluoroquinolones are primarily effective against Gram-negative organisms only.

    <p>False</p> Signup and view all the answers

    Sulfonamides are bacteriostatic and compete with PABA for binding sites.

    <p>True</p> Signup and view all the answers

    Resistance to quinolones and fluoroquinolones can occur through altered target binding, decreased accumulation, and enzymatic degradation.

    <p>True</p> Signup and view all the answers

    Sulfonamides are well absorbed orally, except for sulfasalazine.

    <p>True</p> Signup and view all the answers

    Adverse reactions to quinolones and fluoroquinolones include gastrointestinal and central nervous system effects, tendinitis, and tendon rupture.

    <p>True</p> Signup and view all the answers

    Folate antagonists like sulfonamides inhibit de novo synthesis of pyrimidines.

    <p>False</p> Signup and view all the answers

    Trimethoprim is primarily hepatically metabolized

    <p>False</p> Signup and view all the answers

    Methenamine is effective against E. coli, Enterococcus spp., Staphylococcus spp., and Pseudomonas aeruginosa

    <p>False</p> Signup and view all the answers

    Nitrofurantoin inhibits protein synthesis in bacteria

    <p>False</p> Signup and view all the answers

    Cotrimoxazole is a combination of trimethoprim and sulfamethoxazole

    <p>True</p> Signup and view all the answers

    Resistance to trimethoprim can occur due to altered dihydrofolate reductase

    <p>True</p> Signup and view all the answers

    Nitrofurantoin is the first-line therapy for uncomplicated cystitis

    <p>True</p> Signup and view all the answers

    Rifampin is primarily used to treat multidrug-resistant TB (MDR-TB)

    <p>False</p> Signup and view all the answers

    Isoniazid is a prodrug activated by mycobacterial catalaseperoxidase (KatG)

    <p>True</p> Signup and view all the answers

    Pyrazinamide is active at high pH

    <p>False</p> Signup and view all the answers

    Ethambutol inhibits arabinosyl transferases required for cell wall synthesis

    <p>True</p> Signup and view all the answers

    Antifungal drugs target bacteria's rigid cell wall (chitin) and cell membrane (ergosterol)

    <p>False</p> Signup and view all the answers

    Isoniazid's adverse effects include convulsions and rashes

    <p>True</p> Signup and view all the answers

    Clindamycin is a first-generation quinolone antibiotic

    <p>False</p> Signup and view all the answers

    Clindamycin is effective against MRSA, streptococcus, and anaerobic bacteria

    <p>True</p> Signup and view all the answers

    Fluoroquinolones have an expanded spectrum of activity compared to 1st generation quinolones

    <p>True</p> Signup and view all the answers

    Fluoroquinolones are considered 1st line options for various indications due to resistance to G -ve and G +ve organisms

    <p>False</p> Signup and view all the answers

    Clindamycin is excreted primarily through the kidneys

    <p>False</p> Signup and view all the answers

    C. difficile is resistant to clindamycin treatment

    <p>False</p> Signup and view all the answers

    Amphotericin B is primarily administered orally for systemic mycotic infections

    <p>False</p> Signup and view all the answers

    Amphotericin B binds to ergosterol, disrupting membrane function and causing cell death

    <p>True</p> Signup and view all the answers

    Amphotericin B is extensively distributed in the CSF, vitreous humor, peritoneal fluid, and synovial fluid

    <p>False</p> Signup and view all the answers

    Amphotericin B is primarily excreted through the urine over a long period of time

    <p>True</p> Signup and view all the answers

    Resistance to Amphotericin B is primarily associated with altered ergosterol structure

    <p>True</p> Signup and view all the answers

    Amphotericin B is primarily used for local gastrointestinal tract treatment

    <p>False</p> Signup and view all the answers

    Quinolones and fluoroquinolones are primarily effective against Gram-negative organisms only.

    <p>False</p> Signup and view all the answers

    Sulfonamides are primarily metabolized in the liver through acetylation and conjugation.

    <p>True</p> Signup and view all the answers

    Resistance to quinolones and fluoroquinolones can occur through altered target binding, decreased accumulation, and enzymatic degradation.

    <p>True</p> Signup and view all the answers

    Sulfonamides are well absorbed orally, with high bioavailability for sulfasalazine.

    <p>False</p> Signup and view all the answers

    Adverse reactions to quinolones and fluoroquinolones include hematopoietic disturbances and kernicterus.

    <p>False</p> Signup and view all the answers

    Folate antagonists like sulfonamides are bactericidal and primarily effective against Gram-negative organisms.

    <p>False</p> Signup and view all the answers

    LTBI can be treated for 6 months with isoniazid monotherapy

    <p>False</p> Signup and view all the answers

    Rifampin is primarily used to treat multidrug-resistant TB (MDR-TB)

    <p>False</p> Signup and view all the answers

    Pyrazinamide disrupts mycobacterial cell membrane metabolism and transport functions

    <p>True</p> Signup and view all the answers

    Ethambutol inhibits arabinosyl transferases required for RNA transcription in mycobacteria

    <p>False</p> Signup and view all the answers

    Antifungal drugs primarily target fungi's DNA synthesis

    <p>False</p> Signup and view all the answers

    Increased incidence of mycoses is primarily due to antibiotic resistance

    <p>False</p> Signup and view all the answers

    Trimethoprim is primarily hepatically metabolized

    <p>False</p> Signup and view all the answers

    Methenamine is primarily effective against Escherichia coli and Pseudomonas aeruginosa

    <p>False</p> Signup and view all the answers

    Nitrofurantoin inhibits protein synthesis in bacteria

    <p>False</p> Signup and view all the answers

    Mycobacterium tuberculosis is treated with first-line drugs like isoniazid, rifampin, pyrazinamide, and ethambutol

    <p>True</p> Signup and view all the answers

    Cotrimoxazole has different pharmacokinetics and adverse effects compared to its individual components, trimethoprim and sulfamethoxazole

    <p>False</p> Signup and view all the answers

    Nitrofurantoin is contraindicated in renal insufficiency

    <p>True</p> Signup and view all the answers

    Study Notes

    Antibiotics Pharmacology Lecture Summary

    • Quinolones and fluoroquinolones inhibit bacterial DNA gyrase and topoisomerase IV, leading to rapid cell death.
    • They are effective against Gram-positive and Gram-negative organisms, anaerobic infections, and are used for conditions like anthrax, UTIs, and respiratory infections.
    • Resistance to quinolones and fluoroquinolones can occur through altered target binding, decreased accumulation, and enzymatic degradation.
    • These antibiotics are well absorbed orally, with high bioavailability for levofloxacin and moxifloxacin, but their absorption is affected by certain antacids and supplements.
    • Quinolones and fluoroquinolones are distributed widely in the body, penetrate well into tissues, and are excreted renally.
    • Adverse reactions to quinolones and fluoroquinolones include gastrointestinal and central nervous system effects, tendinitis, tendon rupture, and drug interactions.
    • Folate antagonists like sulfonamides inhibit de novo synthesis of folate, essential for cell growth and division, and are often used in combination with trimethoprim.
    • Sulfonamides compete with PABA, are bacteriostatic, and effective against both Gram-positive and Gram-negative organisms.
    • Resistance to sulfonamides can occur through natural mechanisms or acquired alterations in cellular permeability and PABA production.
    • Sulfonamides are well absorbed orally, except for sulfasalazine, and are widely distributed in the body, including the central nervous system and placental barrier.
    • Metabolism of sulfonamides involves acetylation and conjugation in the liver, with potential adverse effects like crystalluria and kidney damage.
    • Adverse effects of sulfonamides include crystalluria, hypersensitivity, hematopoietic disturbances, kernicterus, and contraindications for specific patient populations.

    Pharmacology Overview by Dr. Osama Abusara

    • Trimethoprim is a potent inhibitor of bacterial dihydrofolate reductase, selectively toxic to bacteria, and prevents the formation of folic acid.
    • Trimethoprim is 20-50 times more potent than sulfonamides and can be used alone for UTIs and bacterial prostatitis.
    • Resistance to trimethoprim can occur due to altered dihydrofolate reductase.
    • Trimethoprim is rapidly absorbed after oral administration, widely distributed, and primarily renally excreted.
    • Adverse effects of trimethoprim include megaloblastic anemia, leukopenia, and hyperkalemia.
    • Cotrimoxazole, a combination of trimethoprim and sulfamethoxazole, has a similar spectrum, resistance, pharmacokinetics, and adverse effects to the individual drugs.
    • Methenamine and nitrofurantoin are urinary tract antiseptics used for treatment or suppression of UTIs.
    • Methenamine is hydrolyzed to ammonia and formaldehyde in acidic urine, denaturing bacterial cell components.
    • Methenamine is effective against E. coli, Enterococcus spp., Staphylococcus spp., and some activity against Proteus and Pseudomonas aeruginosa.
    • Methenamine has adverse effects such as GI distress and is contraindicated in renal insufficiency.
    • Nitrofurantoin is the first-line therapy for uncomplicated cystitis, inhibiting DNA and RNA synthesis.
    • Mycobacterium tuberculosis causes tuberculosis (TB), and its treatment involves first-line drugs like isoniazid, rifampin, pyrazinamide, and ethambutol, with second-line drugs used for resistant TB or intolerance.

    Pharmacology Overview by Dr. Osama Abusara

    • Trimethoprim is a potent inhibitor of bacterial dihydrofolate reductase, selectively toxic to bacteria, and prevents the formation of folic acid.
    • Trimethoprim is 20-50 times more potent than sulfonamides and can be used alone for UTIs and bacterial prostatitis.
    • Resistance to trimethoprim can occur due to altered dihydrofolate reductase.
    • Trimethoprim is rapidly absorbed after oral administration, widely distributed, and primarily renally excreted.
    • Adverse effects of trimethoprim include megaloblastic anemia, leukopenia, and hyperkalemia.
    • Cotrimoxazole, a combination of trimethoprim and sulfamethoxazole, has a similar spectrum, resistance, pharmacokinetics, and adverse effects to the individual drugs.
    • Methenamine and nitrofurantoin are urinary tract antiseptics used for treatment or suppression of UTIs.
    • Methenamine is hydrolyzed to ammonia and formaldehyde in acidic urine, denaturing bacterial cell components.
    • Methenamine is effective against E. coli, Enterococcus spp., Staphylococcus spp., and some activity against Proteus and Pseudomonas aeruginosa.
    • Methenamine has adverse effects such as GI distress and is contraindicated in renal insufficiency.
    • Nitrofurantoin is the first-line therapy for uncomplicated cystitis, inhibiting DNA and RNA synthesis.
    • Mycobacterium tuberculosis causes tuberculosis (TB), and its treatment involves first-line drugs like isoniazid, rifampin, pyrazinamide, and ethambutol, with second-line drugs used for resistant TB or intolerance.

    Antimycobacterial Drugs Overview

    • Tuberculosis (TB) treatment ranges from months to years, with at least 6 months for TB and 2 years for multidrug-resistant TB (MDR-TB)
    • LTBI can be treated for 9 months with isoniazid monotherapy
    • Standard TB regimen involves multiple drugs, while MDR-TB requires 2nd line drugs and any effective drug from 1st line
    • Isoniazid is a prodrug activated by mycobacterial catalaseperoxidase (KatG) and targets enzymes required for mycolic acid synthesis
    • Resistance to isoniazid can result from mutation or deletion of KatG, mutations of acyl carrier proteins, or overexpression of InhA
    • Rifampin, a broader spectrum antimycobacterial drug, blocks RNA transcription and is bactericidal against intracellular and extracellular mycobacteria
    • Pyrazinamide disrupts mycobacterial cell membrane metabolism and transport functions, is active at low pH, and used for a short period in combination with other drugs
    • Ethambutol, specific for mycobacteria, inhibits arabinosyl transferases required for cell wall synthesis
    • Antifungal drugs target fungi's rigid cell wall (chitin) and cell membrane (ergosterol)
    • Increased incidence of mycoses is due to various reasons such as cancer chemotherapy, HIV, and organ transplantation causing immune suppression
    • Isoniazid's adverse effects include hepatitis, peripheral neuropathy, convulsions, rashes, fever, and drug-drug interactions
    • Rifampin's adverse effects include nausea, vomiting, rash, GI upset, flu-like syndrome, and rare hepatitis and death; rifabutin may be used as an alternative

    Pharmacology Overview by Dr. Osama Abusara

    • Trimethoprim is a potent inhibitor of bacterial dihydrofolate reductase, selectively toxic to bacteria, and prevents the formation of folic acid.
    • Trimethoprim is 20-50 times more potent than sulfonamides and can be used alone for UTIs and bacterial prostatitis.
    • Resistance to trimethoprim can occur due to altered dihydrofolate reductase.
    • Trimethoprim is rapidly absorbed after oral administration, widely distributed, and primarily renally excreted.
    • Adverse effects of trimethoprim include megaloblastic anemia, leukopenia, and hyperkalemia.
    • Cotrimoxazole, a combination of trimethoprim and sulfamethoxazole, has a similar spectrum, resistance, pharmacokinetics, and adverse effects to the individual drugs.
    • Methenamine and nitrofurantoin are urinary tract antiseptics used for treatment or suppression of UTIs.
    • Methenamine is hydrolyzed to ammonia and formaldehyde in acidic urine, denaturing bacterial cell components.
    • Methenamine is effective against E. coli, Enterococcus spp., Staphylococcus spp., and some activity against Proteus and Pseudomonas aeruginosa.
    • Methenamine has adverse effects such as GI distress and is contraindicated in renal insufficiency.
    • Nitrofurantoin is the first-line therapy for uncomplicated cystitis, inhibiting DNA and RNA synthesis.
    • Mycobacterium tuberculosis causes tuberculosis (TB), and its treatment involves first-line drugs like isoniazid, rifampin, pyrazinamide, and ethambutol, with second-line drugs used for resistant TB or intolerance.

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    Description

    Test your knowledge of antibiotics pharmacology with this quiz covering quinolones, fluoroquinolones, and sulfonamides. Learn about their mechanisms of action, indications, resistance mechanisms, pharmacokinetics, and adverse effects.

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