[Usefulness of pirenzepine in the study of the upper digestive tract and the large intestine with double contrast media: comparison with scopolamine methylbromide].

The purpose of the present study is to assess the importance of pirenzepine, a selective M1 antimuscarinic drug, as hypotonic agent for diagnostic double-contrast studies of the upper gastrointestinal tract and for double-contrast barium enema studies of the large bowel. Pirenzepine and scopolamine methylbromide (SMB) (Buscopan) were compared in a single blind randomized trial. One hundred-thirty consecutive patients were enrolled in the study. Seventy of them underwent double-contrast studies of the stomach and duodenum and sixty double-contrast barium enema studies of the large bowel. Visceral distension and painting of stomach, duodenal bulb and large bowel and global quality of the images were blindly evaluated by 4 independent observers by means of a numerical score (1 to 4). Quantitative analysis of bowel distension was done measuring the maximum diameter of the transverse colon before and after drug administration. No differences were found in the diagnostic performance between the two drugs in the study of the duodenal bulb (2.8 +/- 0.8 vs 2.9 +/- 0.7, p = NS) and of the large bowel (3.0 +/- 0.6 vs 3.1 +/- 0.6, p = NS). Under SMB, slightly but significantly better results were obtained in the stomach (3.0 +/- 0.6 vs 2.7 +/- 0.6, p = 0.01). However, large bowel distension was slightly but significantly improved with Pirenzepine (68 +/- 12 vs 65 +/- 8 mm, p = 0.02). Heart rate and rhythm during the study were recorded by ECG. SMB induced tachycardia in all patients while pirenzepine did not. Moreover, after SMB, 3 patients exhibited faintness, some patients complained of visual accommodation defects, dryness of the mouth and dizziness. Under pirenzepine, no side-effects were reported. To conclude, pirenzepine gives good results in double contrast studies, as good as SMB but with no adverse effects; thus, it could be proposed as the hypotonic agent of choice in upper gastrointestinal and large bowel examinations.