The ocular effects of hyoscine-n-butylbromide ("Buscopan") in radiological practice.

"Buscopan" (hyoscine-n-butylbromide, HBB) is a smooth muscle relaxant regularly used in radiological and endoscopic procedures. One unwanted effect is temporary impairment of visual accommodation. Near and distance vision were assessed in 100 patients undergoing barium meal and barium enema studies. Visual testing was performed prior to the examination and repeated immediately before leaving the radiology department. Completed data was obtained in 90 patients. Of these, 37 were given a conventional 20 mg intravenous dose of HBB, 37 were given glucagon and 16 received no drug. No patient showed any impairment of distance vision. Minor abnormalities of near vision were observed in five patients. All had been given HBB. They were aged 50 years or less and had been retested 12-21 min after administration of the drug. It is suggested that the degree of visual impairment observed is not sufficient to impair driving ability. Routine questioning concerning history of glaucoma is unlikely to be of value; more appropriate would be a warning to seek urgent medical advice if eye pain or visual loss is experienced.