DAPSONE

Sulphones are drugs of choice for the therapy of all forms of leprosy. Mucosal lesions are first to respond; oral, nasal, pharyngeal, and laryngeal nodules, infiltrations, and ulcerations regress and disappear, and secondary infections subside. Invasion of the peripheral nerves probably occurs in all cases of leprosy, but it is prominent in the tuberculoid form of the disease. The involved extremity is painful and swollen. Patients harbour ‘M. leprae’ in mucous membranes, skin, and nerves long after superficial lesions have disappeared.

Indications

-Leprosy (Hansen's disease) -Dermatitis herpetiformis -Pneumocystis jiroveci pneumonia (PCP) prophylaxis -Various skin conditions with inflammatory components

Dosage

-Leprosy: Adults typically take 50-100 mg daily, often in combination with other anti-leprosy medications. -Dermatitis Herpetiformis: Initial dosage is usually 50 mg daily, which may be adjusted based on patient response and tolerance. -PCP Prophylaxis: 100 mg daily or 50 mg twice daily.

Contra-Indications

-Known hypersensitivity to dapsone or any of its components -Severe anemia -Severe G6PD deficiency (due to the risk of hemolysis)

Special Precautions

-Treatment should be initiated with a small dose & the quantity than increased gradually. Paediatrics: Reduced dose necessary. Pregnancy: Use with caution. Lactation: Use with caution. Elderly: Reduced dose may be necessary. -Regular monitoring of blood counts is necessary to detect potential hematologic side effects. -Caution in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency. -Patients should be monitored for signs of liver dysfunction. -Use cautiously in individuals with preexisting liver disease.

Side Effects

-Hemolysis of varying degree -Methemoglobinemia & Heinz-body formation -Anorexia -Nausea -Vomiting -Headache -Nervousness -Insomnia -Blurred vision -Erythema nodosum leprosum.

Drug Interactions

-Rifampicin: May increase the clearance of dapsone, reducing its efficacy. -Trimethoprim: Concomitant use can increase the risk of hematologic toxicity. -Probenecid: Can decrease renal clearance of dapsone, potentially increasing its levels and risk of toxicity.