Dapsone is a diamino diphenyl sulfone used in the treatment of leprosy. It is also active against certain protozoa.
Indications.
- When combined with pyrimethamine, it is an alternative to sulfadoxine-pyrimethamine for the management of;
√P. falciparum.
√Toxoplasma gondii infections.
√ Fungus Pneumocystis jirovecii
√Chloroquine-resistant malaria.
√ Toxoplasmosis.
Mechanism of action.
By inhibiting the bacterial synthesis of dihydrofolic acid by competing with PABA
Adverse effects.
- Mild hemolytic anemia. It is dose-related toxicity that reflects the oxidizing property of the drug.
√Patients with G-6-PD deficiency are more susceptible.
- Nausea and anorexia are common in the beginning but decrease later.
- Methaemoglobinaemia, paresthesias, headache, mental symptoms, and drug fever.
- Hepatitis and agranulocytosis.
- Cutaneous reactions include allergic rashes, phototoxicity, hyper melanosis, fixed drug eruption, and exfoliative dermatitis.
- Sulfone syndrome; Occurs 4-6 weeks after starting the treatment. It is characterized by;
√fever
√Body weakness
√ lymph node enlargement
√desquamation of skin
√ jaundice
√anemia.
Contraindications.
- Patients with severe anemia
- Patients showing hypersensitivity reaction
- Patients with G-6-PD deficiency.
Drug interactions.
- Probenecid reduces the excretion of the drug from the
Body.
Dose.
- 1-2 mg/kg daily.
