All Free Pharmacology MCQs with Answers

• A. Methicillin
• B. Carbenicillin
• C. Lincomycin
• D. Oxacillin

Explanation: Carbenicillin is an antipseudomonal penicillin with activity against Pseudomonas and certain Proteus species, including indole-positive…

• A. Have no side effects
• B. Do not cause superinfections
• C. Are safer to use during pregnancy
• D. Have a wider range of antibacterial activity

Explanation: Tetracyclines inhibit a broad range of bacteria, including many organisms not covered by penicillins, so their main advantage here is…

• A. Ampicillin
• B. Penicillin
• C. Clindamycin
• D. Cephalosporin

Explanation: Clindamycin is classically associated with Clostridioides difficile overgrowth and pseudomembranous colitis because it markedly disrupts…

• A. Optic nerve
• B. Facial nerve
• C. Auditory nerve
• D. Trigeminal nerve

Explanation: Streptomycin is an aminoglycoside that can cause irreversible ototoxicity, particularly affecting the vestibular and auditory portions of…

• A. Cell wall
• B. Cell membrane
• C. Protein
• D. DNA

Explanation: Chloramphenicol binds the 50S ribosomal subunit and inhibits peptidyl-transferase, thereby blocking bacterial protein synthesis.

• A. Reduced because of enhanced hepatic drug metabolism
• B. Reduced because of increased protein binding
• C. Increased because of reduction of vitamin sources
• D. Increase because of decrease renal excretion of the anticoagulant

Explanation: Broad-spectrum antibiotics reduce intestinal bacteria that normally contribute to vitamin K production, lowering clotting-factor synthesis…

• A. Isoniazid
• B. Ethambutol
• C. Rifampicin
• D. Pirazinamide

Explanation: Isoniazid can cause peripheral neuritis by promoting functional vitamin B6 deficiency, so pyridoxine is often given prophylactically.

• A. Cholestatic Jaundice
• B. Grey Syndrome
• C. Fanconi Syndrome
• D. Jarish - Herxheimer reaction

Explanation: Rapid killing of Treponema pallidum after penicillin can release inflammatory products and produce the Jarisch-Herxheimer reaction, with…

• A. Disphenyl hydantoin
• B. Diphenhydramine
• C. Digoxin
• D. Doxycycline

Explanation: Doxycycline, a tetracycline, binds calcium in developing teeth and bones, causing permanent tooth discoloration and enamel defects.

• A. Pemphigus
• B. Herpes simplex
• C. Candidiasis
• D. Syphilis

Explanation: Fluconazole inhibits fungal ergosterol synthesis and is commonly used for Candida infections, including mucosal and systemic candidiasis.

• A. Benzathine
• B. Procaine
• C. Crystalline
• D. Benzathamine

Explanation: Crystalline penicillin, meaning aqueous penicillin G, can be administered intravenously for serious infections.

• A. Tetracycline
• B. Aminoglycoside
• C. Penicillin
• D. Cephalosporin

Explanation: Tetracyclines can cause photosensitivity because they make the skin more reactive to ultraviolet light.

• A. Lincomycin
• B. Chloramphenicol
• C. Erythromycin
• D. Penicillin

Explanation: Tetracyclines are bacteriostatic, whereas penicillins work best against actively multiplying bacteria, so the combination may antagonize…

• A. Neisseria meningitis
• B. Neisseria gonorrhoeae
• C. Treponema Pallidum
• D. All of the above

Explanation: Penicillin has traditional activity against susceptible Neisseria meningitidis and Neisseria gonorrhoeae and remains the classic treatment…

• A. Ethambutol
• B. Isoniazid
• C. Rifampicin
• D. Streptomycin

Explanation: Streptomycin is an aminoglycoside that can damage cranial nerve VIII, producing vestibular or auditory ototoxicity during prolonged…

• A. Are bacteriostatic
• B. Distributed only extracellularly
• C. Excreted unchanged in urine
• D. Teratogenic

Explanation: Aminoglycosides are bactericidal, not bacteriostatic, because they cause misreading of mRNA and inhibit protein synthesis irreversibly.

• A. Cephapirin
• B. Cefadroxil
• C. Cefaclor
• D. Cefixime

Explanation: Cefadroxil is an orally active first-generation cephalosporin. Cephapirin is parenteral first generation, while cefaclor and cefixime…

• A. Ceftrioxone
• B. Cefaclor
• C. Cefepime
• D. Cefuroxime

Explanation: Cefepime is a fourth-generation cephalosporin with broad Gram-negative activity and useful antipseudomonal coverage.

• A. Has no side-effects
• B. Is used in management of ANUG
• C. Is mainly concentrated in saliva
• D. Is active against gram-positive aerobes

Explanation: Metronidazole is used in acute necrotizing ulcerative gingivitis because it is effective against the associated anaerobic bacteria.

• A. Rifampicin
• B. Ethionamide
• C. Cycloserine
• D. Ethambutol

Explanation: Isoniazid and ethionamide have cross-resistance because both interfere with mycolic-acid synthesis through related activation and target…