新しいヒスタミンH₂受容体遮断薬Ranitidineの臨床薬理学的検討

抄録

The pharmacokinetics of ranitidine, a new H₂-receptor blocking agent, and its effects on tetragastrin-induced gastric acid serection were studied in five healthy volunteers. The ranitidine concentrations in plasma and urine were determined by HPLC.
After single oral administration of ranitidine (100 mg or 150 mg tablet), the peak plasma concentration of the drug was attained in 2-2.5 hrs and the elimination half-life was 2-2.5 hrs when they were obtained from the 24-hr plasma concentration-time curve. After the administration of 100 mg and 150 mg, the maximum plasma levels were in the ratio of 1: 1.57 and the AUCs were, 1: 1.53 which were roughly coincident with the dose ratio. Recovery of unmetabolized ranitidine from urine over a 24-hr period accounted for 40-45% of the administered drug.
In the multiple oral doses of ranitidine (150mg b. i d., for 14 days), the actually measured plasma concentrations of the drug were nearly in agreement with the simulation curves obtained from the single dose.
A single dose of ranitidine (150mg/10ml) significantly reduced gastric volume rate and the output concentration of the acid induced by tetragastrin.
No abnormality attributable to ranitidine was noted in physical findings, clinical laboratory findings or subjective symptoms.