Pharmacokinetics and bioavailability of famotidine in 10 Chinese healthy volunteers

The pharmacokinetics and bioavailability of famotidine were investigated by HPLC method in 10 Chinese healthy volunteers. Data obtained from HPLC were analysed automatically using a MCPKP program on microcomputer. Linear pharmacokinetics were observed following either iv or po administration. After 20 mg iv, plasma levels declined biexponentially with an initial T1/2 of 0.3 +/- 0.2 h and terminal T1/2 of 3.5 +/- 0.8 h. The plasma elimination T1/2 following po administration were 3.4 +/- 0.7 h and 3.5 +/- 0.5 h for capsules and tablets respectively. Oral absorption was incomplete. The absolute bioavailabilities were 38 +/- 10% for capsules and 43 +/- 11% for tablets. Renal excretion was the major route of elimination. About 72% of the dose were recovered as unchanged famotidine in urine. Mean renal and plasma clearance were 416 and 541 ml.min-1 respectively.