Pharmacokinetics of pirenzepine in patients with gastric or duodenal ulcers.

1. The pharmacokinetics of pirenzepine (Gastrozepin) was studied after single and multiple oral administration in gastric ulcer and duodenal ulcer patients. 2. With a dose of 50 mg of pirenzepine, plasma levels reached a maximum 2 h after the administration in both groups (gastric ulcer patients: 57.2 +/- 31.8 ng/ml, duodenal ulcer patients: 48.0 +/- 18.0 ng/ml), and decreased bi-phasically with an elimination half-life (t1/2 beta) of 13.9 +/- 4.0 and 17.9 +/- 4.5 h, respectively. The area under the plasma level curve were 844 +/- 319 ng X h/ml and 663 +/- 151 ng X h/ml in the respective group. 3. The plasma levels of pirenzepine after multiple administration (50 mg was given as a loading dose, and thereafter 25 mg was given as a maintenance dose at an interval of 12 h for 7 days) maintained certain steady state levels from just after the start of administration. 4. It can be concluded that there is no significant difference in the pharmacokinetics of pirenzepine between gastric and duodenal ulcer patients. It can be judged that twice-daily administration of pirenzepine is enough for ulcer treatment.