Usefulness and safety of pirenzepine in double-contrast study of upper gastrointestinal tract: comparison with scopolamine methylbromide.

To evaluate usefulness of pirenzepine, a selective M1 antimuscarinic drug, for diagnostic double-contrast study of the upper gastrointestinal tract, pirenzepine and scopolamine methylbromide (SMB) were compared in a single blind randomized trial. Seventy consecutive patients were enrolled in the study. Artifacts, bowel distention, painting of stomach and duodenal bulb, and global quality of the images were blindly evaluated by four independent observers by means of a numerical score (1-4). Under SMB slightly but significantly better results for stomach were scored (3.1 +/- .7 vs. 2.7 +/- 7, p < 0.01). No differences were found in the study of the duodenal bulb. Heart rate and rhythm during the study were recorded by electrocardiogram (ECG). SMB induced tachycardia in all patients (from 77 +/- 20 to 117 +/- 28 beats/min, p < 0.01) while pirenzepine did not (from 77 +/- 16 to 81 +/- 23, p = NS). After SMB, two patients exhibited faintness, and some patients complained of visual accommodation defects, dryness of the mouth, and dizziness. Thus, pirenzepine provides good results in double-contrast studies (equal to SMB), while presenting no adverse effects. It could be proposed as a first choice hypotonic agent in upper gastrointestinal examination.