Miscellaneous antibiotics – Chloramphenicol and Clindamycin MCQs With Answer

Miscellaneous antibiotics – Chloramphenicol and Clindamycin MCQs With Answer

This concise guide reviews miscellaneous antibiotics with a focus on Chloramphenicol and Clindamycin for B. Pharm students. It covers mechanism of action, pharmacokinetics, clinical uses, adverse effects such as aplastic anemia and pseudomembranous colitis, resistance mechanisms (CAT enzyme, erm methylase, D-test), drug interactions, dosing considerations, neonatal toxicity (Gray baby syndrome) and monitoring parameters. Emphasis is placed on therapeutic indications, tissue penetration (CSF, bone), hepatic metabolism and safety monitoring to deepen understanding beyond basics. The questions are designed to reinforce knowledge essential for pharmacology, therapeutics and clinical pharmacy practice. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. Which is the primary mechanism of action of chloramphenicol?

• Inhibition of 30S ribosomal subunit initiation
• Inhibition of cell wall synthesis by binding PBPs
• Inhibition of 50S peptidyl transferase activity
• Disruption of DNA gyrase activity

Correct Answer: Inhibition of 50S peptidyl transferase activity

Q2. Gray baby syndrome after chloramphenicol administration in neonates is primarily due to which mechanism?

• Immature renal tubular secretion
• Immature hepatic glucuronidation leading to drug accumulation
• Enhanced intestinal absorption in neonates
• Neonatal hypersensitivity causing vasodilation

Correct Answer: Immature hepatic glucuronidation leading to drug accumulation

Q3. Which hematologic adverse effect is classically associated with chloramphenicol and may be irreversible?

• Hemolytic anemia
• Aplastic anemia
• Iron deficiency anemia
• Thrombocytosis

Correct Answer: Aplastic anemia

Q4. What is the primary mechanism of action of clindamycin?

• Inhibition of DNA-dependent RNA polymerase
• Binds 30S subunit and causes misreading
• Binds 50S ribosomal subunit at 23S rRNA inhibiting peptide translocation
• Disrupts bacterial cell membrane integrity

Correct Answer: Binds 50S ribosomal subunit at 23S rRNA inhibiting peptide translocation

Q5. The most important and common serious adverse effect of clindamycin that must be monitored is:

• Nephrotoxicity
• Pseudomembranous colitis due to Clostridioides difficile
• Ototoxicity
• Bone marrow aplasia

Correct Answer: Pseudomembranous colitis due to Clostridioides difficile

Q6. Chloramphenicol’s antimicrobial spectrum includes which of the following?

• Only gram-positive cocci
• Primarily atypical mycobacteria
• Broad-spectrum including many gram-positive, gram-negative, anaerobes and rickettsiae
• Only anaerobes and fungi

Correct Answer: Broad-spectrum including many gram-positive, gram-negative, anaerobes and rickettsiae

Q7. Clindamycin is particularly useful clinically for which types of infections?

• Systemic gram-negative sepsis
• Skin and soft tissue infections, bone infections and anaerobic infections above the diaphragm
• Urinary tract infections caused by E. coli
• Viral respiratory infections

Correct Answer: Skin and soft tissue infections, bone infections and anaerobic infections above the diaphragm

Q8. The most common mechanism of bacterial resistance to chloramphenicol is:

• Target site mutation in 30S subunit
• Release of beta-lactamases
• Enzymatic inactivation by chloramphenicol acetyltransferase (CAT)
• Alteration of folate synthesis

Correct Answer: Enzymatic inactivation by chloramphenicol acetyltransferase (CAT)

Q9. Clindamycin resistance due to methylation of 23S rRNA is mediated by which gene family, and is detected by which laboratory test?

• tet genes and the E-test
• erm genes and the D-test (double-disk diffusion)
• mecA gene and PCR only
• bla genes and nitrocefin test

Correct Answer: erm genes and the D-test (double-disk diffusion)

Q10. Which laboratory monitoring is essential during prolonged chloramphenicol therapy?

• Liver enzymes weekly only
• Complete blood count (CBC) with differential periodically
• Serum creatinine daily
• Coagulation profile weekly

Correct Answer: Complete blood count (CBC) with differential periodically

Q11. Chloramphenicol can interact with warfarin and phenytoin primarily because it:

• Induces CYP450 enzymes, decreasing their levels
• Directly displaces them from plasma proteins causing toxicity
• Inhibits hepatic drug-metabolizing enzymes, increasing their plasma levels
• Enhances renal clearance of these drugs

Correct Answer: Inhibits hepatic drug-metabolizing enzymes, increasing their plasma levels

Q12. Which pharmacokinetic property describes clindamycin?

• Poor tissue penetration and exclusive renal excretion
• Good bone and soft tissue penetration with primarily hepatic metabolism and biliary excretion
• Minimal oral bioavailability and no hepatic metabolism
• Rapid renal elimination unchanged

Correct Answer: Good bone and soft tissue penetration with primarily hepatic metabolism and biliary excretion

Q13. Chloramphenicol is generally classified as bacteriostatic; under what circumstance can it be bactericidal?

• When combined with aminoglycosides
• Against highly susceptible organisms where minimum inhibitory concentration is low
• Only at subtherapeutic concentrations
• Never bactericidal under any conditions

Correct Answer: Against highly susceptible organisms where minimum inhibitory concentration is low

Q14. For detection of early bone marrow toxicity from chloramphenicol, which test is most informative?

• Serum iron and ferritin
• Reticulocyte count and periodic CBC monitoring
• Serum B12 level
• Urinalysis

Correct Answer: Reticulocyte count and periodic CBC monitoring

Q15. Chloramphenicol is contraindicated or used with extreme caution in neonates primarily because:

• They have increased renal clearance causing subtherapeutic levels
• They lack effective hepatic glucuronidation causing toxicity
• They have high plasma protein binding preventing effect
• They rapidly metabolize it to inactive forms

Correct Answer: They lack effective hepatic glucuronidation causing toxicity

Q16. Clindamycin is a preferred oral option for which clinical scenario?

• Severe gram-negative bacteremia
• Mild to moderate community-acquired skin and soft tissue infections where MRSA coverage is needed
• Uncomplicated cystitis due to E. coli
• Systemic fungal infections

Correct Answer: Mild to moderate community-acquired skin and soft tissue infections where MRSA coverage is needed

Q17. Dose-related reversible bone marrow suppression is associated with which antibiotic?

• Clindamycin
• Chloramphenicol
• Metronidazole
• Linezolid

Correct Answer: Chloramphenicol

Q18. Bacterial resistance to chloramphenicol may be mediated by which of the following mechanisms?

• Mutation in DNA gyrase
• Enzymatic acetylation of the drug rendering it inactive
• Overproduction of PABA
• Beta-lactamase production

Correct Answer: Enzymatic acetylation of the drug rendering it inactive

Q19. Pseudomembranous colitis following clindamycin therapy occurs due to:

• Direct mucosal toxicity of clindamycin
• Overgrowth and toxin production by Clostridioides difficile after disruption of normal gut flora
• Allergic reaction to clindamycin causing colitis
• Immune complex deposition in colonic vasculature

Correct Answer: Overgrowth and toxin production by Clostridioides difficile after disruption of normal gut flora

Q20. The primary route of elimination for clindamycin is:

• Renal excretion of unchanged drug
• Hepatic metabolism with biliary excretion
• Exhalation as unchanged drug
• Glomerular filtration only

Correct Answer: Hepatic metabolism with biliary excretion

Q21. Cross-resistance between clindamycin and macrolides is mainly due to which mechanism?

• Efflux pumps specific for beta-lactams
• Methylation of 23S rRNA by erm genes
• Alteration of DNA topoisomerase
• Reduced cell wall permeability

Correct Answer: Methylation of 23S rRNA by erm genes

Q22. Which laboratory method is used to detect inducible clindamycin resistance in staphylococci?

• Broth microdilution only
• D-test (double-disk diffusion test)
• Kirby-Bauer with penicillin disk
• Latex agglutination

Correct Answer: D-test (double-disk diffusion test)

Q23. Chloramphenicol undergoes which major metabolic pathway in the liver?

• Oxidation by monoamine oxidase
• Glucuronidation
• CYP3A4-mediated demethylation only
• Sulfation exclusively

Correct Answer: Glucuronidation

Q24. Which adverse effect is unique to chloramphenicol compared to clindamycin?

• Pseudomembranous colitis
• Aplastic anemia
• Rash and pruritus
• Transient elevation of transaminases

Correct Answer: Aplastic anemia

Q25. Which formulation of chloramphenicol is commonly used for topical ocular infections?

• Intramuscular sterile solution
• Ophthalmic ointment or drops
• Inhalation nebulizer solution
• Transdermal patch

Correct Answer: Ophthalmic ointment or drops

Q26. Clindamycin belongs to which antibiotic class?

• Aminoglycosides
• Lincosamides
• Fluoroquinolones
• Sulfonamides

Correct Answer: Lincosamides

Q27. Which anaerobic pathogen has shown increasing resistance to clindamycin and requires susceptibility testing?

• Bacteroides fragilis
• Clostridioides difficile
• Peptostreptococcus anaerobius
• Propionibacterium acnes

Correct Answer: Bacteroides fragilis

Q28. The idiosyncratic aplastic anemia associated with chloramphenicol is best described as:

• Predictable and dose-dependent
• Rare, idiosyncratic and often irreversible
• Always reversible on drug withdrawal
• Limited to neonates only

Correct Answer: Rare, idiosyncratic and often irreversible

Q29. Chloramphenicol is still used in resource-limited settings for which central nervous system infection due to its excellent CSF penetration?

• Tuberculous meningitis exclusively
• Bacterial meningitis caused by susceptible organisms (e.g., H. influenzae, S. pneumoniae in penicillin-allergic patients)
• Viral encephalitis
• Cryptococcal meningitis

Correct Answer: Bacterial meningitis caused by susceptible organisms (e.g., H. influenzae, S. pneumoniae in penicillin-allergic patients)

Q30. If a patient on clindamycin develops severe watery diarrhea and abdominal pain, the most appropriate immediate action is:

• Continue clindamycin and prescribe loperamide
• Discontinue clindamycin and evaluate for C. difficile infection
• Increase the dose of clindamycin to overcome resistance
• Switch to oral metronidazole without further evaluation

Correct Answer: Discontinue clindamycin and evaluate for C. difficile infection

G S Sachin

I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.

Mail- Sachin@pharmacyfreak.com