FAMOTIDINE PHARMACOKINETICS IN PATIENTS UNDERGOING CARDIAC-SURGERY

In order to study the pharmacokinetics of famotidine in cardiac surger y patients, we administered famotidine 20mg by intravenous injection a t the beginning of surgery and 12 hours after surgery in 8 patients un dergoing elective cardiac surgery with cardiopulmonary bypass. Total b ody clearance, volume of distribution, and elimination half-life were calculated using noncompartmental analysis and compared with published normal parameters (control) using a 2-tailed, 1-sample t-test. Intra- and postoperative clearances were 2.93 +/- 1.06 and 3.18 +/- 1.06 ml/ min/kg, respectively, which were more than 50% less than the control v alue (6.07 ml/min/kg; p<0.0005). The volume of distribution (1.0 L/kg) was unaltered during the study and did not differ from the control va lue (1.19 L/kg; p>0.08). Intra- and postoperative half-lives were 4.52 +/- 2.21 hours and 4.27 +/- 1.58 hours, respectively, which were more than 50% longer than control (2.92 hours; p<0.03). Famotidine pharmac okinetics are significantly altered during cardiac surgery with cardio pulmonary bypass, and these changes persist for up to 24 hours after s urgery.