50 MCQs on Antimicrobial Drugs

50 MCQs on Antimicrobial Drugs for Pharmacy License and Pharmacy Loksewa Exam.

1. Which of the following antimicrobials acts by inhibiting cell wall synthesis?
a) Ciprofloxacin
b) Rifampicin
c) Penicillin
d) Azithromycin

2. Which antimicrobial has a narrow spectrum and is effective primarily against Gram-positive bacteria?
a) Cephalexin
b) Penicillin G
c) Ciprofloxacin
d) Amikacin

3. Which of the following is a bacteriostatic antimicrobial?
a) Gentamicin
b) Doxycycline
c) Amoxicillin
d) Vancomycin

4. Which antimicrobial is primarily effective against protozoa?
a) Metronidazole
b) Amikacin
c) Ketoconazole
d) Ethambutol

5. Which antimicrobial belongs to the beta-lactam group?
a) Azithromycin
b) Cefuroxime
c) Doxycycline
d) Streptomycin
Answer: b) Cefuroxime

6. What is the major determinant of the efficacy of a time-dependent antimicrobial?
a) Peak concentration
b) Total exposure
c) Time above the minimum inhibitory concentration (MIC)
d) Volume of distribution

7. What does the term “post-antibiotic effect” (PAE) refer to?
a) Persistent bacterial suppression after drug levels drop below MIC
b) Bactericidal effect during drug infusion
c) Resistance development after prolonged use
d) Allergic reaction after stopping therapy

8. Combination antimicrobial therapy is used to:
a) Reduce adverse effects
b) Decrease resistance risk
c) Enhance spectrum of activity
d) All of the above

9. Which of the following is a mechanism of microbial resistance to beta-lactams?
a) Enzymatic degradation by beta-lactamases
b) Alteration of DNA gyrase
c) Efflux pump activation
d) Target modification of the 50S ribosome

10. Which of the following bacteria typically exhibit intrinsic resistance to vancomycin?
a) E. coli
b) Streptococcus pyogenes
c) Pseudomonas aeruginosa
d) Enterococcus faecium

11. Co-trimoxazole is a combination of:
a) Sulfamethoxazole and trimethoprim
b) Sulfasalazine and ampicillin
c) Sulfadiazine and rifampicin
d) Silver sulfadiazine and erythromycin

12. Which of the following is a major side effect of sulfonamides?
a) Hepatotoxicity
b) Stevens-Johnson syndrome
c) Ototoxicity
d) Nephrotoxicity

13. Which of the following is a penicillinase-resistant penicillin?
a) Amoxicillin
b) Cloxacillin
c) Benzylpenicillin
d) Ampicillin

14. Which penicillin is commonly used for syphilis?
a) Amoxicillin
b) Benzathine penicillin
c) Ampicillin
d) Cloxacillin

15. Which cephalosporin is third-generation?
a) Cephalexin
b) Cefuroxime
c) Cefotaxime
d) Cefaclor

16. Which cephalosporin is active against anaerobes?
a) Cefuroxime
b) Cefoxitin
c) Cephalexin
d) Cefaclor

17. Clavulanic acid acts by:
a) Inhibiting bacterial DNA synthesis
b) Inhibiting beta-lactamase enzymes
c) Blocking protein synthesis
d) Disrupting bacterial membranes

18. Which of the following is a contraindication for tetracycline use?
a) Diabetes
b) Pregnancy
c) Hypertension
d) Liver disease

19. A major side effect of doxycycline is:
a) Hepatotoxicity
b) Photosensitivity
c) Nephrotoxicity
d) Ototoxicity

20. Which aminoglycoside is used for tuberculosis?
a) Gentamicin
b) Streptomycin
c) Amikacin
d) Kanamycin

21. A common side effect of aminoglycosides is:
a) Nephrotoxicity
b) Hepatotoxicity
c) Hypersensitivity
d) Peripheral neuropathy

22. Which fluoroquinolone is effective against Pseudomonas?
a) Ciprofloxacin
b) Norfloxacin
c) Ofloxacin
d) Nitrofurantoin

23. Quinolones act by:
a) Inhibiting DNA gyrase
b) Inhibiting RNA polymerase
c) Blocking protein synthesis
d) Disrupting cell wall synthesis

24. Which first-line antitubercular drug causes red-orange discoloration of body fluids?
a) Rifampicin
b) INH
c) Pyrazinamide
d) Ethambutol

25. Which antileprotic drug is known for causing skin discoloration?
a) Dapsone
b) Clofazimine
c) Rifampicin
d) Ethambutol

26. What is the mechanism of action of dapsone?
a) Inhibits dihydropteroate synthase
b) Inhibits RNA polymerase
c) Disrupts cell wall synthesis
d) Blocks DNA gyrase

27. Which antifungal drug binds to ergosterol and forms pores in the fungal membrane?
a) Fluconazole
b) Ketoconazole
c) Nystatin
d) Griseofulvin

28. Which antifungal drug inhibits fungal mitosis by binding to microtubules?
a) Griseofulvin
b) Amphotericin B
c) Clotrimazole
d) Fluconazole

29. What is the most common side effect of amphotericin B?
a) Nephrotoxicity
b) Hepatotoxicity
c) Neurotoxicity
d) Ototoxicity

30. Which antifungal drug is commonly used for treating systemic candidiasis?
a) Fluconazole
b) Ketoconazole
c) Nystatin
d) Clotrimazole

31. Which antiviral drug is used for the treatment of influenza A?
a) Amantadine
b) Acyclovir
c) Zidovudine
d) Oseltamivir

32. Which of the following antiretroviral drugs is a reverse transcriptase inhibitor?
a) Ritonavir
b) Zidovudine
c) Dolutegravir
d) Enfuvirtide

33. Acyclovir is effective against:
a) Influenza A virus
b) Herpes simplex virus
c) Hepatitis B virus
d) HIV

34. Which antimalarial drug is effective in treating both blood and liver stages of malaria?
a) Chloroquine
b) Primaquine
c) Quinine
d) Artemisinin

35. What is the mechanism of action of chloroquine?
a) Inhibition of heme polymerization
b) Disruption of mitochondrial function
c) Interference with DNA synthesis
d) Blocking protein synthesis

36. Which antimalarial drug is most effective against chloroquine-resistant P. falciparum?
a) Artemisinin
b) Primaquine
c) Quinine
d) Sulfadoxine

37. Metronidazole is effective against:
a) Malaria
b) Amebiasis
c) Tuberculosis
d) Fungal infections

38. Which of the following is a major side effect of metronidazole?
a) Ototoxicity
b) Disulfiram-like reaction
c) Photosensitivity
d) Hepatotoxicity

39. Diloxanide furoate is primarily used for:
a) Cryptosporidiosis
b) Amebiasis
c) Giardiasis
d) Malaria

40. Albendazole acts by:
a) Inhibiting glucose uptake in worms
b) Depolarizing neuromuscular junctions
c) Disrupting DNA synthesis
d) Blocking microtubule synthesis

41. Which antihelminthic is used to treat hydatid cysts?
a) Praziquantel
b) Albendazole
c) Niclosamide
d) Diethylcarbamazine

42. Praziquantel is effective against:
a) Roundworms
b) Cestodes and trematodes
c) Nematodes
d) Filariasis

43. Diethylcarbamazine is used to treat:
a) Cysticercosis
b) Filariasis
c) Schistosomiasis
d) Ascariasis

44.A patient with a urinary tract infection caused by E. coli is prescribed norfloxacin. What is the mechanism of action of this drug?
a) Inhibits topoisomerase II (DNA gyrase)
b) Inhibits cell wall synthesis
c) Blocks folate synthesis
d) Binds to 50S ribosomal subunit

45. A patient with tuberculosis develops peripheral neuropathy. Which drug is the likely cause?
a) INH
b) Rifampicin
c) Pyrazinamide
d) Ethambutol

46. A pregnant woman with a vaginal yeast infection is prescribed an antifungal. Which is the safest option?
a) Nystatin
b) Fluconazole
c) Ketoconazole
d) Amphotericin B

47. Which antimicrobial should be avoided in children due to potential cartilage damage?
a) Ciprofloxacin
b) Amoxicillin
c) Azithromycin
d) Doxycycline

48. What is the most common side effect of aminoglycosides?
a) Nephrotoxicity
b) Hepatotoxicity
c) Cardiotoxicity
d) Neurotoxicity

49. Which drug is used to treat amebiasis in asymptomatic carriers?
a) Diloxanide furoate
b) Metronidazole
c) Tinidazole
d) Paromomycin

50. Which drug combination is used as a first-line treatment for leprosy?
a) Rifampicin, dapsone, and clofazimine
b) Rifampicin, INH, and pyrazinamide
c) Ciprofloxacin, dapsone, and PAS
d) Amikacin, rifampicin, and clofazimine

Answers:

1. C	2. B	3. B	4. A	5. B
6. C	7. A	8. D	9. A	10. C
11. A	12. B	13. B	14. B	15. C
16. B	17. B	18. B	19. B	20. B
21. A	22. A	23. A	24. A	25. B
26. A	27. C	28. A	29. A	30. A
31. A	32. B	33. B	34. B	35. A
36. A	37. B	38. B	39. B	40. D
41. B	42. B	43. B	44. A	45. A
46. A	47. A	48. A	49. A	50. A