Absorption of orally administered sodium sulfate in humans.

Sodium sulfate can be used to enhance the conjugation of phenolic drugs with sulfate and to treat hypercalcemia. It is thought that sulfate in is absorbed slowly and incompletely from the digestive tract. The purposes of this investigation were to determine the absorption of large amount of sodium sulfate (18.1 g as the decahydrate, equivalent to 8.0 g of the anhydrous salt) and to compare the bioavailability when this amount is administered orally to normal subjects as a single dose and as four equally divided hourly doses. The 72-hr urinary recovery of free sulfate following single and divided doses was 53.4 +/- 15.8 and 61.8 +/- 7.8%, respectively (mean +/- SD, n=5, p greater than 0.2). The single dose produced severe diarrhea while the divided doses caused only mild or no diarrhea. Thus, a large amount of sodium sulfate, when administered orally in divided doses over 3 hr, is well tolerated and is absorbed to a significant extent. Orally administered sodium sulfate may be useful for the early treatment of acetaminophen overdose.