dapsone: clinical use

Prescribing considerations

• Confirm the licensed indication and, where relevant, use within appropriate combination therapy.
• Assess anaemia, G6PD status and cardiopulmonary disease before treatment.
• Explain early symptoms of haemolysis, methaemoglobinaemia, agranulocytosis and dapsone hypersensitivity syndrome.
• Review pregnancy, breastfeeding and interacting medicines before initiation.

Contraindications and cautions

• Hypersensitivity to dapsone, sulfonamides, sulfones or product excipients
• Severe anaemia
• Porphyria
• Severe G6PD deficiency

Monitoring

• Baseline G6PD assessment is usually performed.
• Check full blood count and liver and renal function before and during treatment; tailor ongoing frequency to clinical risk and results.
• Assess promptly for falling haemoglobin, haemolysis, methaemoglobinaemia, liver injury, severe rash, infection or neuropathy.

Clinical pharmacology

Dapsone is well absorbed orally and undergoes hepatic acetylation and oxidation. Its hydroxylamine metabolite contributes to haemolysis and methaemoglobinaemia; enterohepatic recirculation and variable metabolism contribute to prolonged and variable elimination.

Formulation and product differences

• The selected product is a white to off-white, uncoated, scored tablet that can be divided into equal portions.
• It contains microcrystalline cellulose, maize starch, colloidal anhydrous silica and magnesium stearate.
• The selected product is supplied in PVC–aluminium blister packaging.

Tablet

Route: Oral

Strengths: 50 mg, 100 mg