1999 Volume 59 Issue 2 Pages 84-88
The decrement of bioavailability (BA) of lomerizine hydrochloride after oral administration to low-acidity patients was expected because of the decrement of dissolution rate of lomerizine hydrochloride from tablets at low pH. We investigated the effect of gastric acidity on the BA of lomerizine hydrochloride after oral administration, using dogs that were treated with pentagastrin or cimetidine. The gastric pH is 2.1 ± 0.3 and 7.4 ± 0.4 after the treatment of pentagastrin and cimetidine, respectively. Cimetidine, which reduces the blood flow in liver and inhibits metabolic enzymes, has not affected the pharmacokinetics of lomerizine after intravenous administration of lomerizine hydrochloride. The plasma concentration of lomerizine after oral administration of lomerizine hydrochloride tablets (5 mg tablet × 6) after the treatment of pentagastrine was very closed to that of cimetidine, and there was no difference of the pharmacokinetic parameters between both treatments. Therefore, gastric acidity should have no effect on the BA of lomerizine hydrochloride in patients.
