Absorption of sulfate from orally administered magnesium sulfate in man

The purpose of this investigation was to determine the suitability of orally administered magnesium sulfate as a source of inorganic sulfate for counteracting the systemic depletion of sulfate caused by large doses of acetaminophen and certain other drugs that are metabolized to sulfate conjugates. Oral administration of 13.9 g magnesium sulfate U.S.P., in 4 equal hourly increments, to seven healthy men resulted in the urinary excretion (corrected for baseline excretion rate) of an amount of inorganic sulfate equivalent to 30.2 +/- 17.2 percent (mean +/- SD) of the dose during the first 24 hours. Excretion during the subsequent 48 hours was negligible. Six of the subjects experienced loose stools or diarrhea. Compared to sodium sulfate, magnesium sulfate appears to be absorbed less completely and more erratically, and to produce more adverse effects.