Leishmaniasis drugs – Pentamidine, Atovaquone, Eflornithine MCQs With Answer

Introduction

Leishmaniasis drugs – Pentamidine, Atovaquone, Eflornithine MCQs With Answer

Leishmaniasis is a complex protozoal infection requiring targeted antileishmanial therapy. This concise introduction reviews three important agents — Pentamidine, Atovaquone, and Eflornithine — addressing mechanisms of action, pharmacokinetics, clinical indications, adverse effects, resistance, and combination therapy. Pentamidine acts on nucleic acids and mitochondrial function; Atovaquone inhibits the parasite cytochrome bc1 complex; Eflornithine irreversibly inhibits ornithine decarboxylase, disrupting polyamine synthesis. B. Pharm students will benefit from focused understanding of dosing considerations, monitoring parameters, drug interactions, and safety profiles relevant to antileishmanial treatment. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. Which is the primary molecular target of eflornithine (DFMO) in protozoal parasites?

• Isoleucyl-tRNA synthetase
• Ornithine decarboxylase
• DNA gyrase
• Cytochrome bc1 complex

Correct Answer: Ornithine decarboxylase

Q2. Atovaquone exerts antiparasitic action mainly by inhibiting which mitochondrial component?

• ATP synthase (Complex V)
• Succinate dehydrogenase (Complex II)
• Cytochrome bc1 complex (Complex III)
• NADH dehydrogenase (Complex I)

Correct Answer: Cytochrome bc1 complex (Complex III)

Q3. Which common adverse effect is most associated with pentamidine therapy?

• Nephrotoxicity and hypoglycemia
• Bone marrow suppression
• Hemolytic anemia
• Visual field constriction

Correct Answer: Nephrotoxicity and hypoglycemia

Q4. Which statement about the pharmacokinetics of atovaquone is correct?

• Atovaquone is highly water-soluble and renally excreted unchanged
• It has poor oral bioavailability enhanced by fatty meals
• It is rapidly metabolized by CYP3A4 to active metabolites
• It penetrates CSF well due to low protein binding

Correct Answer: It has poor oral bioavailability enhanced by fatty meals

Q5. Eflornithine is classified pharmacologically as which type of inhibitor?

• Reversible competitive inhibitor of ODC
• Irreversible (suicide) inhibitor of ornithine decarboxylase
• Allosteric activator of polyamine synthesis
• Non-specific DNA alkylating agent

Correct Answer: Irreversible (suicide) inhibitor of ornithine decarboxylase

Q6. Which clinical form of leishmaniasis has historically been treated with pentamidine?

• Visceral leishmaniasis (kala-azar) exclusively
• Cutaneous leishmaniasis only
• Some cases of cutaneous and mucocutaneous leishmaniasis
• Pneumocystis jirovecii pneumonia (not leishmaniasis)

Correct Answer: Some cases of cutaneous and mucocutaneous leishmaniasis

Q7. Which monitoring parameter is most important during pentamidine therapy?

• Serum creatinine and blood glucose
• Serum potassium only
• INR and aPTT
• Serum bilirubin

Correct Answer: Serum creatinine and blood glucose

Q8. Resistance to atovaquone in protozoa is commonly due to mutations in which gene product?

• Ornithine decarboxylase
• Cytochrome b (cyt b) of the bc1 complex
• P-glycoprotein efflux pump exclusively
• Dihydrofolate reductase

Correct Answer: Cytochrome b (cyt b) of the bc1 complex

Q9. Which adverse effect is particularly associated with prolonged eflornithine therapy?

• Neurotoxicity and seizures
• Severe renal tubular necrosis
• Ototoxicity leading to deafness
• Cardiac arrhythmias due to QT prolongation

Correct Answer: Neurotoxicity and seizures

Q10. Which drug interaction is clinically relevant for atovaquone?

• Atovaquone reduces warfarin effect via CYP induction
• Concurrent tetracyclines markedly increase atovaquone levels
• Proguanil shows synergistic antiprotozoal effect with atovaquone
• Co-administration with rifampin increases atovaquone bioavailability

Correct Answer: Proguanil shows synergistic antiprotozoal effect with atovaquone

Q11. What is the principal clinical use of eflornithine in parasitology?

• Treatment of Plasmodium falciparum malaria
• First-line therapy for mucocutaneous leishmaniasis
• Treatment of Trypanosoma brucei gambiense (sleeping sickness)
• Prophylaxis of Pneumocystis pneumonia

Correct Answer: Treatment of Trypanosoma brucei gambiense (sleeping sickness)

Q12. Which route of administration is common for pentamidine in systemic infection?

• Oral tablet daily
• Intravenous or intramuscular injection
• Topical cream
• Nebulized inhalation only

Correct Answer: Intravenous or intramuscular injection

Q13. Which laboratory change is a known effect of pentamidine therapy?

• Hyperkalemia due to renal retention
• Hypoglycemia followed by hyperglycemia due to pancreatic beta-cell toxicity
• Marked neutrophilia
• Elevated transaminases only without renal effects

Correct Answer: Hypoglycemia followed by hyperglycemia due to pancreatic beta-cell toxicity

Q14. Which principle best explains atovaquone’s selectivity for parasites over human cells?

• Parasites lack mitochondria, so they are unaffected
• Parasitic bc1 complex differs sufficiently in drug-binding site
• Atovaquone is activated by parasitic phosphatases only
• Human cells rapidly export atovaquone via ABC transporters

Correct Answer: Parasitic bc1 complex differs sufficiently in drug-binding site

Q15. Which dosing consideration is important for oral atovaquone administration?

• Take on an empty stomach for best absorption
• Take with a high-fat meal to increase bioavailability
• Avoid co-administration with antacids only
• Administer as an IV infusion to avoid first-pass metabolism

Correct Answer: Take with a high-fat meal to increase bioavailability

Q16. Which mechanism contributes to eflornithine’s antiparasitic effect?

• Inhibition of folate synthesis
• Depletion of polyamines causing impaired cell division
• Cross-linking of parasite DNA strands
• Blocking glucose uptake by the parasite

Correct Answer: Depletion of polyamines causing impaired cell division

Q17. Which adverse effect is commonly monitored with atovaquone therapy?

• Severe nephrotoxicity requiring dialysis
• Gastrointestinal upset and rash
• Marked bone marrow suppression
• Permanent peripheral neuropathy

Correct Answer: Gastrointestinal upset and rash

Q18. Which statement about pentamidine’s mechanism is most accurate?

• Pentamidine inhibits DHFR like trimethoprim
• It interferes with nucleic acid and mitochondrial function and polyamine metabolism
• It acts exclusively as a cell wall synthesis inhibitor
• It functions by chelating essential iron in the parasite

Correct Answer: It interferes with nucleic acid and mitochondrial function and polyamine metabolism

Q19. What is a major limitation to widespread use of eflornithine in resource-limited settings?

• Oral tablet formulation only—no IV option
• High cost and need for prolonged IV infusion with monitoring
• Severe irreversible renal toxicity
• Rapid development of resistance after single dose

Correct Answer: High cost and need for prolonged IV infusion with monitoring

Q20. Which of the following drug combinations has been investigated for synergistic antileishmanial effect?

• Atovaquone plus proguanil
• Pentamidine plus aminoglycoside antibiotic
• Eflornithine plus chloroquine
• Atovaquone plus eflornithine

Correct Answer: Atovaquone plus proguanil

Q21. Which precaution is essential when preparing pentamidine for IV infusion?

• Use glucose-containing solution exclusively
• Monitor infusion rate and observe for hypotension and arrhythmia
• No monitoring required as pentamidine is well tolerated
• Always mix with calcium-containing solutions

Correct Answer: Monitor infusion rate and observe for hypotension and arrhythmia

Q22. Which laboratory test is important before initiating eflornithine?

• Baseline EEG only
• Complete blood count due to risk of bone marrow suppression
• Urine culture routinely
• Lipid profile monitoring

Correct Answer: Complete blood count due to risk of bone marrow suppression

Q23. Which statement about uptake of pentamidine into Leishmania is correct?

• Uptake is entirely by passive diffusion independent of transporters
• Parasite surface transporters and endocytosis contribute to uptake
• Uptake requires activation by parasite kinases in cytosol
• It enters only via mitochondrial pores

Correct Answer: Parasite surface transporters and endocytosis contribute to uptake

Q24. Which patient factor reduces oral atovaquone absorption and may require dosing adjustment?

• Concurrent high-fat meal
• Underlying severe diarrhea or malabsorption
• Co-administration with proguanil
• Elevated serum albumin levels

Correct Answer: Underlying severe diarrhea or malabsorption

Q25. Which pharmacodynamic characteristic best describes eflornithine’s action?

• Concentration-dependent killing with post-antibiotic effect
• Time-dependent inhibition of polyamine biosynthesis
• Bacteriostatic via cell wall synthesis inhibition
• Immediate membrane disruption causing lysis

Correct Answer: Time-dependent inhibition of polyamine biosynthesis

Q26. Which of the following is a recognized clinical use of atovaquone outside leishmaniasis?

• Treatment of Pneumocystis jirovecii pneumonia (second-line or prophylaxis)
• First-line therapy for bacterial sepsis
• Management of acute myocardial infarction
• Topical antifungal for dermatophytes

Correct Answer: Treatment of Pneumocystis jirovecii pneumonia (second-line or prophylaxis)

Q27. In the context of combination therapy for protozoal infections, why combine eflornithine with another drug?

• To decrease cost by using lower doses of both
• To prevent emergence of resistance and achieve synergistic killing
• Because eflornithine is inactive alone in all protozoa
• To shorten IV infusion time to a single dose

Correct Answer: To prevent emergence of resistance and achieve synergistic killing

Q28. Which toxic effect necessitates immediate cessation of pentamidine?

• Mild transient nausea
• Development of acute renal failure or severe hypoglycemia
• Minor injection-site soreness
• Temporary hair loss

Correct Answer: Development of acute renal failure or severe hypoglycemia

Q29. Which formulation property of atovaquone influences its distribution?

• Low protein binding leading to wide tissue distribution
• High lipid solubility and high plasma protein binding leading to large volume of distribution in fatty tissues
• Quaternary ammonium structure limiting cell penetration
• Extensive renal tubular secretion

Correct Answer: High lipid solubility and high plasma protein binding leading to large volume of distribution in fatty tissues

Q30. Which mechanism is a known route for the development of resistance to pentamidine in Leishmania?

• Overexpression or mutation of surface transporters reducing drug uptake
• Increased host metabolism of pentamidine by liver enzymes
• Enhanced renal excretion by the parasite
• Upregulation of human immune clearance mechanisms

Correct Answer: Overexpression or mutation of surface transporters reducing drug uptake

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