We evaluated the widely held notion that anticholinergic drugs must be used in near toxic doses to inhibit gastric acid secretion effectively. Nine patients with duodenal ulcer were studied after a low dose (15 mg) and after a near toxic dose (averaging 48 mg) of the anticholinergic, propantheline. Mean (± S.E.) inhibition of food-stimulated acid secretion was identical with the two doses of propantheline: 29±10 and 29±11 per cent, respectively. In addition, when 15 mg of propantheline was combined with the histamine H2-receptor antagonist, cimetidine, acid secretion was suppressed to a greater degree than with either drug alone. A low dose of propantheline is as effective as a near toxic dose in suppressing food-stimulated acid secretion and augments the inhibitory effect of cimetidine. (N Engl J Med 297:1427–1430,1977) IN 1956 Sun and Shay reported that for anticholinergic drugs to inhibit gastric acid secretion effectively, it was necessary to administer them in an “optimal effective dose,” which is just below the dose at which undesirable side effects (such as blurred vision and dry mouth) occur.1 Since sensitivity to anticholinergics varies widely among individual patients, the optimal effective dose must be carefully determined for each patient by a process of dose titration over several days. The dose can vary from one to eight times the manufacturer's recommended dose.2 The importance of using an optimal effective dose has been widely accepted.
ASJC Scopus subject areas