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Drugs Used in Leprosy Treatment
Dapsone (Sulfone)
Mechanism of Action
Dapsone inhibits the synthesis of dihydrofolic acid by blocking *dihydropteroate synthase*, disrupting folic acid production and bacterial growth.
Adverse Effects
- Hemolysis (especially in G6PD deficiency)
- Methemoglobinemia
- Hepatitis
- Skin rashes
- Agranulocytosis
- Peripheral neuropathy (long-term use)
Contraindications
- Hypersensitivity to dapsone
- G6PD deficiency
- Severe hepatic disease
Rifampicin (Rifamycin Antibiotic)
Mechanism of Action
Rifampicin inhibits bacterial RNA synthesis by binding to RNA polymerase, preventing transcription and replication of *Mycobacterium leprae*.
Adverse Effects
- Hepatotoxicity
- Orange discoloration of urine, sweat, and tears
- GI disturbances
- Thrombocytopenia
- Skin rash
- Drug interactions (affects other drugs like warfarin, contraceptives)
Contraindications
- Hypersensitivity to rifampicin
- Severe hepatic impairment
- Concomitant use with certain drugs (e.g., protease inhibitors)
Clofazimine (Riminophenazine)
Mechanism of Action
Clofazimine binds to the DNA of *Mycobacterium leprae*, inhibiting bacterial replication and also has anti-inflammatory properties.
Adverse Effects
- Skin pigmentation (red-brown discoloration)
- Gastrointestinal disturbances
- Dry skin, ichthyosis
- QT interval prolongation
- Hepatotoxicity
- Corneal pigmentation (rare)
Contraindications
- Hypersensitivity to clofazimine
- Pregnancy (Category C)
- Severe liver or renal impairment
Thalidomide (Used for Leprosy Reactions)
Mechanism of Action
Thalidomide has immunomodulatory properties, inhibiting TNF-alpha and IL-6, helping in the treatment of leprosy reactions like erythema nodosum leprosum (ENL).
Adverse Effects
- Teratogenicity (severe birth defects)
- Peripheral neuropathy
- Sedation
- Constipation
- Risk of DVT or PE
- Rash
Contraindications
- Pregnancy (absolute contraindication)
- Women of childbearing potential (unless using proper contraception)
- Severe renal or hepatic impairment
Corticosteroids (For Leprosy Reactions)
Mechanism of Action
Corticosteroids reduce inflammation by suppressing the migration of leukocytes and the release of pro-inflammatory cytokines, used mainly in leprosy reactions.
Adverse Effects
- Weight gain
- Hypertension
- Hyperglycemia
- Osteoporosis
- Increased risk of infections
- Cataracts
- Psychiatric effects (mood swings, depression)
Contraindications
- Systemic fungal infections
- Active tuberculosis
- Uncontrolled diabetes
- Gastric ulcers
