Effect of dapsone on haemoglobin concentration in patients with leprosy.

Haemolysis and frank anaemia from dapsone therapy of leprosy has been long recognized. However, the frequency and severity of this side-effect have not been well documented. We report herein a retrospective analysis of the effect of daily dapsone (generally 100 mg/day) on the haemoglobin concentration of 100 leprosy patients undergoing initial chemotherapy. The average haemoglobin was found to fall significantly by almost 2 g/dl, from 14.25 +/- 1.27 g/dl to a nadir of 12.31 +/- 1.61 (P less than 0.001). Eighty-three percent of patients had a fall of haemoglobin concentration of 1 g/dl or more, while in 16% of patients the haemoglobin fell greater than or equal to 3 g/dl. Increasing age was found associated with an increased magnitude of dapsone-related haemolysis (P less than or equal to 0.004). Decreasing the daily dose of dapsone was associated with an increased haemoglobin concentration (P less than 0.001%). We have concluded that dapsone commonly results in not only haemolysis but a significant decrease in haemoglobin concentration. This may have serious clinical implications, especially in endemic areas, where, owing to nutrition, malaria, and intestinal parasitism, the haemoglobin concentration is already compromised.