PH8.6 | PH8.6 | Leprosy Pharmacotherapy — SDL Guide — Summary & Reflection

KEY TAKEAWAYS

WHO MDT regimens: PB leprosy (1–5 lesions): rifampicin 600mg monthly (supervised) + dapsone 100mg daily × 6 months. MB leprosy (>5 lesions or smear+): rifampicin 600mg monthly + clofazimine 300mg monthly (supervised) + clofazimine 50mg + dapsone 100mg daily × 12 months.

Drug mechanisms and key ADRs: Rifampicin — RNA polymerase β; bactericidal (only bactericidal drug in MDT); CYP inducer (OCP failure); orange secretions. Dapsone — dihydropteroate synthase; bacteriostatic; haemolytic anaemia (severe in G6PD deficiency — screen before use); methaemoglobinaemia; dapsone hypersensitivity syndrome (4–6 weeks). Clofazimine — DNA binding + anti-inflammatory; bacteriostatic + anti-ENL; orange-brown skin pigmentation (warn patient — reversible); GI effects.

Lepra reactions: Type 1 (Reversal) — Type IV (T-cell CMI); borderline leprosy (BT/BB/BL); pre-existing patches become red + tender + nerve involvement; treat with prednisolone 40mg tapering. Type 2 (ENL) — Type III (immune complex/IgM); LL/BL; new erythematous nodules + systemic features; treat with thalidomide (males/non-fertile females only — teratogenic) or clofazimine (fertile women). Both reactions: CONTINUE MDT — do not stop.

G6PD deficiency: substitute dapsone with clofazimine or ofloxacin. Pregnancy: dapsone + rifampicin safe; thalidomide absolutely contraindicated.

REFLECT

Leprosy was eliminated as a public health problem in India by WHO criteria in 2005, yet new cases continue to emerge. Some states report higher-than-expected new case detection rates. Consider the pharmacological factors (incomplete MDT courses, transmission before diagnosis) and the social factors (stigma, delay in presentation, poverty) that sustain leprosy transmission despite an effective cure. As a future clinician, what role would you play in leprosy elimination — not just prescribing MDT, but in your community outreach and advocacy?