Hyoscine-N-Butyl-Bromide-Induced Hypotension and Myocardial Ischemia

Hyoscine N-butyl bromide, also known as scopolamine, is a type of antimuscarinic agent. This drug is associated with numerous common side effects, including abdominal fullness, constipation, urinary retention, blurred vision, skin flushing, tachycardia, decreased sweating, and salivation. The most unfavorable side effect is hemodynamic instability. In the present case, hypotension and acute myocardial infarction developed after intravenous hyoscine injection as a premedication therapy for colonoscopy. It was difficult to differentiate the cause-effect relationship between myocardial infarction and hypotension. Because both conditions were present under drug effects, we considered 2 possible diagnoses. One was coronary spasm with cardiogenic shock, and the other was myocardial ischemic sequela due to shock status. The latter diagnosis was confirmed after a series of examinations. 1. Introduction Hyoscine N-butyl bromide, also known as scopolamine, is a type of antimuscarinic agent; this class of drugs also includes atropine, ipratropium, diphenhydramine, and others. Attachment of the butyl-bromide moiety prevents the movement of this drug across the blood-brain barrier, thereby minimizing its potential neurologic side effects. It is often used as an antispasmodic treatment for the pain and discomfort induced by abdominal cramps or menstrual cramps. Herein, we report a case of hypotension and acute myocardial infarction after intravenous hyoscine injection as premedication for colonoscopy. In this case, it was difficult to discern the cause-effect relationship between myocardial infarction and hypotension. 2. Case Report A 53-year-old woman presented with abdominal cramping pain and bloody diarrhea for 3 days. She was robust prior to this event, with no known relevant medical history. She denied fever or chills. Physical examination revealed increased bowel sounds and tenderness in the lower abdomen. Laboratory tests demonstrated minimal leukocytosis (10,300 cells/μL) without left shift and elevated C-reactive protein. Intravenous ciprofloxacin 400？mg q12？h was prescribed to treat the suspected infectious diarrhea. No specific finding was reported on enterogastroduodenoscopy. Due to suspicion of an infectious or inflammatory process of the lower gastrointestinal tract, colonoscopy was arranged after 3 days of colonic preparation. Hyoscine 20？mg was prescribed via a slow intravenous drip as a premedication for colonoscopy. Unfortunately, loss of consciousness and cyanosis of all 4 limbs developed 1-2 minutes later. The patient’s blood pressure was