What is the drug of choice for leprosy?

DSSSB 14 August 2024

Pharmacology

Easy

Appeared in: DSSSB 14 August 2024

Explanation

Dapsone is the correct answer as it is the oldest, cheapest, and most widely used drug for leprosy, forming the backbone of treatment for decades.
It is a sulfone drug that acts as a competitive antagonist of PABA, inhibiting folic acid synthesis in Mycobacterium leprae, which results in a bacteriostatic effect.
Although modern treatment always uses Multidrug Therapy (MDT) to prevent resistance, Dapsone remains a core and foundational component of all standard WHO-recommended regimens.

Option A: Chloroquine is an antimalarial drug and does not treat the underlying bacterial infection of leprosy.
Option B: Primaquine is an antimalarial drug used to eradicate dormant liver forms of Plasmodium vivax and ovale.
Option D: While Rifampicin is a critical part of modern leprosy treatment, it is not the single 'drug of choice'. Dapsone is considered the foundational agent.

Clinical Relevance

Nursing practice connection: Knowing Pharmacological treatment of Leprosy (Hansen's Disease) helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
The cornerstone of modern leprosy management is Multidrug Therapy (MDT) to prevent the emergence of drug-resistant strains, which was a major problem when Dapsone was used alone.
Nurses play a vital role in patient education regarding strict adherence to the long duration of MDT (6-12 months), recognizing and managing drug side effects (e.g., Dapsone-induced anemia, Clofazimine-induced skin pigmentation), and monitoring for lepra reactions.
What if? If a patient has a known Glucose-6-Phosphate Dehydrogenase (G6PD) deficiency, Dapsone must be used with extreme caution or an alternative regimen considered, as it can trigger severe dose-related hemolytic anemia. Pre-treatment screening is crucial in at-risk populations.

How to Approach the Question

First, identify the core of the question: it asks for the primary or foundational 'drug of choice' for leprosy.
Next, analyze the options provided, which are all antimicrobial agents.
Eliminate the clearly incorrect options. Chloroquine and Primaquine are well-known antimalarial drugs, making them unsuitable for treating a bacterial infection like leprosy.
Differentiate between the remaining plausible options: Dapsone and Rifampicin are both key drugs in leprosy treatment.
Recall the specific roles of each drug. Rifampicin is the most powerful bactericidal agent, but Dapsone is the historical, foundational (leprostatic) drug that has been the 'sheet anchor' of therapy for many years.
Conclude that in the context of a 'drug of choice' question, Dapsone is the most appropriate answer, representing the classic and primary agent around which modern combination therapy is built.

Concept Tested & Keywords

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E6 Pharmacology Nurses Shanbhag 3e p. 317-319

E6 Parks TextBook of Preventive & Social Medicine part 1 — Subpart B (pp 202-403 of 604) p. 187-189

E6 Nelson Textbook of Pediatrics(2024) — Volume 1 p. 1837-1839