Quinacrine hydrochloride and Mefloquine MCQs With Answer — This concise introduction highlights essential pharmacology for B. Pharm students: quinacrine (mepacrine, Atabrine) and mefloquine are antimalarial agents with distinct mechanisms, pharmacokinetics, indications, adverse effects, and resistance profiles. Key topics include mechanisms (DNA intercalation and inhibition of hemozoin formation), long half-life and lipophilicity of mefloquine, neuropsychiatric and vestibular toxicities, drug interactions, contraindications (epilepsy, psychiatric disorders), dosing for prophylaxis, and monitoring. Understanding these concepts aids rational use, safe dispensing, and patient counselling. This material emphasizes clinical relevance, mechanisms, and safe practice for B.Pharm exam preparation. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. Which of the following best describes the primary antiprotozoal action of quinacrine (mepacrine)?
- Intercalation into DNA inhibiting nucleic acid replication
- Selective inhibition of dihydrofolate reductase
- Blocking parasitic protein synthesis at the ribosome
- Activation of parasite-specific proteases
Correct Answer: Intercalation into DNA inhibiting nucleic acid replication
Q2. What is the primary proposed mechanism of action of mefloquine against Plasmodium spp.?
- Inhibition of folate synthesis
- Disruption of heme polymerization (inhibits hemozoin formation)
- Inhibition of mitochondrial electron transport
- Alkylation of parasite DNA
Correct Answer: Disruption of heme polymerization (inhibits hemozoin formation)
Q3. For prophylaxis against chloroquine-resistant P. falciparum, which drug is commonly recommended?
- Quinacrine (mepacrine)
- Mefloquine
- Primaquine alone
- Proguanil monotherapy
Correct Answer: Mefloquine
Q4. What is the usual weekly prophylactic dose of mefloquine for adults (as commonly recommended)?
- 50 mg once weekly
- 250 mg once weekly
- 500 mg daily
- 750 mg every two weeks
Correct Answer: 250 mg once weekly
Q5. Quinacrine hydrochloride is also known by which alternative name?
- Chloroquine
- Mepacrine (Atabrine)
- Halofantrine
- Artemisinin
Correct Answer: Mepacrine (Atabrine)
Q6. Which adverse effect is most characteristically associated with mefloquine?
- Severe nephrotoxicity
- Neuropsychiatric reactions (anxiety, depression, psychosis)
- Marked bone marrow suppression
- Pulmonary fibrosis
Correct Answer: Neuropsychiatric reactions (anxiety, depression, psychosis)
Q7. Mefloquine is contraindicated or used with caution in patients with which history?
- History of controlled hypertension only
- History of epilepsy or major psychiatric disorder
- Mild seasonal allergies
- Past childhood varicella infection
Correct Answer: History of epilepsy or major psychiatric disorder
Q8. Which statement correctly describes the elimination half-life of mefloquine?
- Very short, less than 6 hours
- Moderate, 12–24 hours
- Long, approximately 2–4 weeks
- Extremely long, several years
Correct Answer: Long, approximately 2–4 weeks
Q9. Mefloquine is primarily metabolized by which organ system?
- Renal excretion as unchanged drug
- Hepatic metabolism (CYP-mediated)
- Intestinal bacterial degradation only
- Pulmonary metabolism
Correct Answer: Hepatic metabolism (CYP-mediated)
Q10. Beyond malaria, quinacrine has historically been used to treat which intestinal protozoal infection?
- Entamoeba histolytica dysentery
- Giardiasis (Giardia lamblia)
- Cryptosporidiosis
- Toxoplasmosis
Correct Answer: Giardiasis (Giardia lamblia)
Q11. Resistance to mefloquine is often associated with which parasitic genetic change?
- Point mutations in cytochrome b only
- Amplification of the pfmdr1 gene
- Loss of plasmodial mitochondria
- Mutation in dihydropteroate synthase
Correct Answer: Amplification of the pfmdr1 gene
Q12. Regarding ECG monitoring with mefloquine, which statement is most appropriate?
- Routine ECG monitoring is mandatory for all patients
- No cardiovascular effects are possible, so monitoring is unnecessary
- Monitor ECG when used with other QT-prolonging drugs or in cardiac disease
- ECG monitoring is only needed for pediatric patients
Correct Answer: Monitor ECG when used with other QT-prolonging drugs or in cardiac disease
Q13. Which is the safest guidance about mefloquine use in pregnancy?
- Mefloquine is absolutely contraindicated in all trimesters
- Mefloquine may be used in pregnancy when benefits outweigh risks
- Mefloquine is the first-line choice for pregnant women everywhere
- Mefloquine should be combined with halofantrine in pregnancy
Correct Answer: Mefloquine may be used in pregnancy when benefits outweigh risks
Q14. A notable dermatologic adverse effect of quinacrine is:
- Photosensitivity with blistering
- Pigmentary change or yellow skin discoloration and dermatitis
- Rapid-onset exfoliative dermatitis in all patients
- Permanent alopecia in most users
Correct Answer: Pigmentary change or yellow skin discoloration and dermatitis
Q15. Which symptom is commonly reported with mefloquine related to vestibular dysfunction?
- Hearing loss with tinnitus only
- Episodic vertigo and balance disturbance
- Isolated anosmia
- Peripheral neuropathy with glove-and-stocking pattern
Correct Answer: Episodic vertigo and balance disturbance
Q16. The distribution characteristics of mefloquine can be summarized as:
- Low volume of distribution, stays in plasma
- Highly lipophilic with large volume of distribution and tissue accumulation
- Confined to extracellular fluid only
- Restricted to renal tissue primarily
Correct Answer: Highly lipophilic with large volume of distribution and tissue accumulation
Q17. Quinacrine’s inhibition of parasite growth is primarily due to:
- Disruption of parasitic cell wall synthesis
- Binding to DNA and inhibition of nucleic acid and protein synthesis
- Inhibition of human host immune response
- Chelation of essential serum iron
Correct Answer: Binding to DNA and inhibition of nucleic acid and protein synthesis
Q18. What is the recommended route of administration for mefloquine in prophylaxis and treatment?
- Oral administration
- Intramuscular injection only
- Intravenous infusion only
- Topical application
Correct Answer: Oral administration
Q19. Is mefloquine recommended as first-line therapy for severe, complicated malaria requiring parenteral treatment?
- Yes — it is the preferred IV agent
- No — parenteral artesunate is the recommended treatment for severe malaria
- Yes — but only in combination with doxycycline
- No — only quinine should be used parenterally
Correct Answer: No — parenteral artesunate is the recommended treatment for severe malaria
Q20. Combining mefloquine with halofantrine is discouraged because it increases the risk of:
- Severe hypoglycemia
- Cardiotoxicity and QT prolongation
- Neutropenia exclusively
- Severe renal failure
Correct Answer: Cardiotoxicity and QT prolongation
Q21. Prior to prescribing mefloquine for prophylaxis, which clinical assessment is most important?
- Screening for G6PD deficiency only
- Detailed psychiatric and seizure history assessment
- Baseline pregnancy test in all males
- Immediate liver biopsy
Correct Answer: Detailed psychiatric and seizure history assessment
Q22. Which of the following are recognized therapeutic uses of quinacrine? (Choose best single option)
- Only systemic fungal infections
- Antimalarial and treatment of giardiasis
- Primary agent for tuberculosis
- Exclusive treatment for helminth infections
Correct Answer: Antimalarial and treatment of giardiasis
Q23. In cases of mefloquine overdose, the most serious acute manifestations include:
- Severe neurotoxicity and cardiac arrhythmias
- Isolated painless jaundice only
- Acute pancreatitis as the main finding
- Profound hypocalcemia exclusively
Correct Answer: Severe neurotoxicity and cardiac arrhythmias
Q24. Mefloquine belongs to which chemical/pharmacological class?
- Artemisinin derivatives
- 4-quinoline methanol derivative
- Tetracycline antibiotics
- Sulfonamide class
Correct Answer: 4-quinoline methanol derivative
Q25. When using quinacrine for prolonged therapy, which monitoring parameter is reasonable?
- Regular ophthalmic exams only once per decade
- Periodic liver function tests and blood counts
- No monitoring is required for any parameter
- Daily serum electrolyte checks
Correct Answer: Periodic liver function tests and blood counts
Q26. Mefloquine is primarily active against which stage of the malaria parasite?
- Liver (hypnozoite) stages only
- Blood schizont stages
- Sporozoite stage in the mosquito gut
- Gametocytes exclusively
Correct Answer: Blood schizont stages
Q27. Which statement about oral absorption of quinacrine is correct?
- Poorly absorbed and requires IV dosing for efficacy
- Well absorbed orally with extensive tissue distribution
- Only effective when given with fatty meals sublingually
- Absorption occurs only in the presence of antacids
Correct Answer: Well absorbed orally with extensive tissue distribution
Q28. The primary route of elimination for mefloquine is:
- Renal excretion as unchanged drug
- Biliary excretion and fecal elimination
- Exhalation via lungs
- Metabolism to volatile gases
Correct Answer: Biliary excretion and fecal elimination
Q29. Which statement regarding mefloquine and chloroquine resistance is accurate?
- Mefloquine is always ineffective against chloroquine-resistant strains
- Mefloquine is often effective against chloroquine-resistant P. falciparum
- Mefloquine causes immediate cross-resistance with doxycycline
- Mefloquine and chloroquine are structurally identical and interchangeable
Correct Answer: Mefloquine is often effective against chloroquine-resistant P. falciparum
Q30. What is an important counseling point for patients starting mefloquine prophylaxis?
- There are no side effects, so no monitoring or follow-up is needed
- Avoid alcohol and report any neuropsychiatric symptoms promptly
- Double the dose if you miss a weekly tablet
- Use concurrently with halofantrine to improve efficacy
Correct Answer: Avoid alcohol and report any neuropsychiatric symptoms promptly
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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