Factors influencing the level of dapsone in blood.

The level of dapsone in the blood 4 and 6 h after the ingestion of the 7th daily dose of 100 mg of the drug was investigated in 36 adult males with leprosy who had normal renal function and were free of diarrhoea and emesis. The bimodal distribution of the dapsone levels at 6 h was shown by multiple regression analysis to be due to a negative correlation between this trait and the haematocrit value. Among the patients with high dapsone blood levels, 81.8% presented haematocrit values under 36%, whereas only 20% of those with low levels showed low haematocrit values. Partial regression coefficients, calculated for the dapsone level on the age, weight of the patient, estimated number of years since the onset of leprosy, number of years under sulfone treatment, and blood levels of haemoglobin, albumin, and globulins, did not show statistical significance.