Dose reduction of hyoscine-N-butylbromide for double-contrast barium meal examinations--a prospective randomized study.

A search of the literature suggests that the conventional 20 mg dose of intravenous hyoscine-N-butylbromide (HBB) for smooth muscle relaxation in double-contrast barium meal (DCBM) studies is largely empirical. This study analysed the merits of three different doses (5 mg, 10 mg, 20 mg) in the performance of routine DCBMs. One hundred and twenty DCBM examinations were prospectively and randomly allocated to receive one of three doses. Three parameters were measured for each examination: gastroduodenal distension, delay in gastric emptying and gastric antrum overlapping with barium-filled duodenal loops. Almost half the examinations using 5 mg produced undesirable duodenal-gastric overlay. Unacceptable early flooding of the duodenal bulb with barium was seen mostly with doses of 5 mg and 10 mg. Overall, the best results were obtained with 20 mg. The continued use of 20 mg HBB in routine DCBMs is recommended.