Anthelmintic drugs – classification and examples MCQs With Answer
This concise guide for B.Pharm students covers anthelmintic drugs: classification, representative examples, mechanisms of action, spectra (nematodes, cestodes, trematodes), pharmacokinetics, adverse effects and resistance issues. Key drug classes include benzimidazoles (albendazole, mebendazole), imidazothiazoles (levamisole), tetrahydropyrimidines (pyrantel), macrocyclic lactones (ivermectin), piperazine, praziquantel and diethylcarbamazine. Emphasis is on mode of action (beta‑tubulin binding, neuromuscular blockade, increased Ca2+ permeability, glutamate‑gated chloride channels), clinical uses, contraindications (pregnancy, children), and common interactions. Useful keywords: anthelmintic drugs, classification, examples, mechanisms, albendazole, praziquantel, ivermectin. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. Which of the following is the most common practical classification for anthelmintic drugs used in clinical practice?
- By chemical structure only
- By route of administration
- By type of helminth targeted — nematodes, cestodes, trematodes, or broad‑spectrum
- By country of origin
Correct Answer: By type of helminth targeted — nematodes, cestodes, trematodes, or broad‑spectrum
Q2. Which drug is a benzimidazole that acts by binding to parasite beta‑tubulin and inhibiting microtubule formation?
- Pyrantel pamoate
- Albendazole
- Praziquantel
- Ivermectin
Correct Answer: Albendazole
Q3. Praziquantel is the drug of choice for which type of helminth infection?
- Hookworm anemia
Correct Answer: Cestode and trematode infections such as schistosomiasis and neurocysticercosis
Q4. Which anthelmintic causes spastic paralysis of nematodes by acting as a nicotinic acetylcholine receptor agonist?
- Levamisole
- Piperazine
- Mebendazole
- Diethylcarbamazine
Correct Answer: Levamisole
Q5. Ivermectin primarily targets which receptor/channel in parasites to produce paralysis?
- Beta‑tubulin microtubules
- Glutamate‑gated chloride channels
- Sodium channels in mammalian neurons
- Acetylcholinesterase enzyme
Correct Answer: Glutamate‑gated chloride channels
Q6. Which anthelmintic is contraindicated in pregnancy due to teratogenicity observed in animal studies and recommended to avoid in the first trimester?
- Albendazole
- Praziquantel
- Piperazine
- Pyrantel pamoate
Correct Answer: Albendazole
Q7. Which drug is effective against Enterobius vermicularis (pinworm) and works by inhibiting microtubule polymerization?
- Mebendazole
- Pyrantel pamoate
- Praziquantel
- Ivermectin
Correct Answer: Mebendazole
Q8. Piperazine’s primary mechanism of action in nematodes is:
- Activation of glutamate‑gated chloride channels causing hyperpolarization
- Antagonism of nicotinic receptors causing spastic paralysis
- Binding to beta‑tubulin and inhibiting mitosis
- Inhibition of tegumental enzymes in trematodes
Correct Answer: Activation of glutamate‑gated chloride channels causing hyperpolarization
Q9. Diethylcarbamazine (DEC) is mainly used in the treatment of which condition?
- Schistosomiasis
- Lymphatic filariasis (Wuchereria bancrofti, Brugia species)
Correct Answer: Lymphatic filariasis (Wuchereria bancrofti, Brugia species)
Q10. Which of the following statements about praziquantel is true?
- It inhibits microtubule polymerization in nematodes
- It increases calcium influx in parasites causing tetanic contraction and tegumental disruption
- It is a first‑line drug for onchocerciasis
- It acts by warming parasite GABA receptors to cause flaccid paralysis
Correct Answer: It increases calcium influx in parasites causing tetanic contraction and tegumental disruption
Q11. Which anthelmintic is preferred for treating strongyloidiasis and acts on glutamate‑gated chloride channels?
- Albendazole
- Pyrantel pamoate
- Ivermectin
- Mebendazole
Correct Answer: Ivermectin
Q12. Which class of drugs is associated with the emergence of resistance due to point mutations in parasite beta‑tubulin?
- Benzimidazoles (e.g., albendazole, mebendazole)
- Macrocyclic lactones (e.g., ivermectin)
- Piperazine derivatives
- Praziquantel
Correct Answer: Benzimidazoles (e.g., albendazole, mebendazole)
Q13. For mass drug administration against soil‑transmitted helminths in children, which of the following is commonly used?
- Albendazole single dose
- Diethylcarbamazine single dose
- Praziquantel single dose
- Ivermectin long course
Correct Answer: Albendazole single dose
Q14. Which anthelmintic is known to cause a Mazzotti‑type reaction (intense inflammatory response) when used for onchocerciasis due to rapid microfilarial killing?
- Piperazine
- Ivermectin
- Praziquantel
- Mebendazole
Correct Answer: Ivermectin
Q15. Which drug is effective against both adult tapeworms and larval forms (neurocysticercosis) when combined with corticosteroids to reduce inflammation?
- Albendazole
- Pyrantel pamoate
- Piperazine
- Levamisole
Correct Answer: Albendazole
Q16. Which anthelmintic is primarily used orally and acts as a depolarizing neuromuscular-blocking agent causing spastic paralysis of worms, useful for intestinal roundworms?
- Pyrantel pamoate
- Diethylcarbamazine
- Praziquantel
- Mebendazole
Correct Answer: Pyrantel pamoate
Q17. Which drug’s absorption is enhanced by a fatty meal and is converted to an active sulfoxide metabolite in the liver?
- Albendazole
- Pyrantel pamoate
- Piperazine
- Praziquantel
Correct Answer: Albendazole
Q18. Which anthelmintic is least effective against systemic tissue cysts and is mainly used for intestinal helminths due to poor absorption?
- Albendazole
- Mebendazole
- Ivermectin
- Praziquantel
Correct Answer: Mebendazole
Q19. Which drug works by causing flaccid paralysis of nematodes by acting as a GABA agonist at parasite neuromuscular junctions?
- Piperazine
- Levamisole
- Mebendazole
- Praziquantel
Correct Answer: Piperazine
Q20. Which anthelmintic is commonly used in combination with albendazole for pediatric filariasis control in mass drug administration programs to enhance efficacy?
- Praziquantel
- Ivermectin
- Pyrantel pamoate
- Mebendazole
Correct Answer: Ivermectin
Q21. Which of the following adverse effects is most characteristically associated with albendazole therapy?
- Severe ototoxicity
- Transient elevation of liver enzymes and rare hepatotoxicity
- Permanent vision loss
- Renal tubular necrosis
Correct Answer: Transient elevation of liver enzymes and rare hepatotoxicity
Q22. Nitazoxanide is an antiparasitic with broad activity; its main use among helminth infections is limited. Which other pathogen class is it primarily used against?
- Bacterial infections like tuberculosis
- Protozoa and some viruses (e.g., Giardia, Cryptosporidium, rotavirus)
- Fungal infections like Candida
- Prion diseases
Correct Answer: Protozoa and some viruses (e.g., Giardia, Cryptosporidium, rotavirus)
Q23. Which statement about levamisole is correct?
- It is mainly used for cestode infections
- It is an anthelmintic that acts as a nicotinic receptor agonist and can cause agranulocytosis rarely
- It inhibits microtubules and causes teratogenicity
- It is contraindicated in all adults
Correct Answer: It is an anthelmintic that acts as a nicotinic receptor agonist and can cause agranulocytosis rarely
Q24. Which anthelmintic is effective against hydatid disease (Echinococcus) when used for prolonged therapy or as preoperative treatment?
- Pyrantel pamoate
- Albendazole
- Piperazine
- Levamisole
Correct Answer: Albendazole
Q25. Which of the following drugs is primarily indicated for intestinal tapeworms and works by causing tegumental damage and spastic paralysis?
- Praziquantel
- Piperazine
- Albendazole
- Mebendazole
Correct Answer: Praziquantel
Q26. Resistance to ivermectin in veterinary helminths involves selection at what general level?
- Parasite behavioral avoidance only
- Genetic mutations affecting drug targets and transporters
- Increased human host immunity
- Reduced environmental drug stability
Correct Answer: Genetic mutations affecting drug targets and transporters
Q27. Which anthelmintic is preferred for treatment of trichuriasis (whipworm) in many programs, often combined with albendazole for broader coverage?
- Praziquantel
- Mebendazole
- Ivermectin
- Piperazine
Correct Answer: Mebendazole
Q28. In neurocysticercosis management, why are corticosteroids often co‑administered with albendazole?
- To increase absorption of albendazole
- To reduce inflammatory reaction from dying parasites and limit cerebral edema
- To potentiate microtubule inhibition
- To directly kill the parasite faster
Correct Answer: To reduce inflammatory reaction from dying parasites and limit cerebral edema
Q29. Which of these drugs has a mechanism primarily involving inhibition of parasite fumarate reductase and is more an antiprotozoal than a classical anthelmintic?
- Nitazoxanide
- Pyrantel pamoate
- Diethylcarbamazine
- Mebendazole
Correct Answer: Nitazoxanide
Q30. Which precaution is important when using praziquantel in patients with ocular cysticercosis?
- No precaution is needed—safe in all cases
- Caution because rapid parasite killing can provoke vision‑threatening inflammation; treat with steroids and ophthalmic monitoring
- Give praziquantel only with live vaccines
- Combine praziquantel with high‑dose aspirin to reduce inflammation
Correct Answer: Caution because rapid parasite killing can provoke vision‑threatening inflammation; treat with steroids and ophthalmic monitoring
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.
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