On the Influence of Concomitant Food Intake on Sulfonamide Bioavailability

Abstract

The influence of food intake on the bioavailability of a frequently used short-acting sulfonamide, sulfaisodimidine (Elkosin), was examined in 8 healthy volunteers. The drug was administered as a single oral dose, both on an empty stomach and together with a standardized breakfast. Numerous venous blood samples were drawn for the first 8 h after ingestion of the drug, and the concentration of unmetabolized sulfonamide in serum was assessed by spectrophotometry. Concomitant food intake probably altered neither absorption rate, peak concentration, time to reach peak concentration, elimination rate, nor total amount of sulfonamide reaching the general circulation. The absorption of orally administered sulfaisodimidine was not at all affected by concomitant intake of food. This contrasted with previous observations on some other sulfonamides, and it probably signified a therapeutic advantage of sulfaisodimidine. In addition, the amount absorbed showed only a little interindividual variation. The use of standardized size and interval of sulfaisodimidine dosage was recommended. Conclusions about the absorption of a certain drug should not be derived from studies with other, albeit chemically related, compounds.