The fate of cimetidine sulphoxide in the guinea pig

Abstract

1. An oral dose of cimetidine given to guinea pigs was totally excreted in 3 days, divided equally between urine and faeces.

2. Only 40% of an oral dose of cimetidine sulphoxide was voided in 3 days, the remainder being found in the mesentery and omental tissues.

3. In contrast, 90% of an i.v. dose of cimetidine sulphoxide was excreted in urine in 24 h.

4. Approx. 20% of an oral dose of both cimetidine (17.2%) and cimetidine sulphoxide (24.9%) was secreted in bile during the first day.

5. The major metabolic routes encountered were sulphoxidation and sulphoxide reduction.