Hyoscine Butylbromide (Buscopan) Side Effects and Safety Profile
Hyoscine butylbromide causes typical anticholinergic side effects including dry mouth, urinary retention, blurred vision, tachycardia, and drowsiness, with the most serious concern being cardiovascular complications including hypotension and myocardial ischemia in at-risk patients. 1
Common Side Effects
The FDA-approved labeling identifies the following adverse reactions associated with hyoscine butylbromide 1:
Anticholinergic Effects (Most Frequent)
- Dry mouth – the most commonly reported side effect 1
- Urinary hesitancy and retention 1
- Blurred vision and mydriasis (pupil dilation) 1
- Increased ocular tension 1
- Decreased sweating – can lead to heat prostration or heat stroke in febrile patients or those exposed to elevated temperatures 1
Cardiovascular Effects
- Tachycardia and palpitations 1
- Hypotension – can be severe and lead to hemodynamic instability 2
- Myocardial ischemia – documented case reports show acute myocardial infarction following intravenous administration 2
Neurological Effects
- Drowsiness, dizziness, and fatigue – patients should be warned not to operate machinery or drive 1
- Headache and nervousness 1
- Mental confusion and excitement (especially in elderly patients) 1
- Short-term memory loss and hallucinations 1
- Central anticholinergic syndrome – though hyoscine butylbromide is a quaternary ammonium compound that poorly crosses the blood-brain barrier, hyoscine hydrobromide (a related compound) can cause severe agitation and delirium 3
Gastrointestinal Effects
Other Effects
- Allergic reactions including urticaria and dermal manifestations 1
- Loss of taste 1
- Impotence 1
- Ataxia and speech disturbance 1
Contraindications
Absolute Contraindications 1, 4
- Tachycardia – anticholinergics increase heart rate 1, 4
- Angina pectoris 4
- Cardiac failure 4
- Prostatic hypertrophy with urinary retention 1, 4
- Gastroparesis or conditions requiring prokinetic therapy – anticholinergics slow gastric emptying and worsen gastroparesis 5
- Recent bowel anastomosis 5
Precautions and High-Risk Populations
Cardiac Patients Require Careful Monitoring 6, 4
- The Canadian Association of Gastroenterology emphasizes that cardiac complications are more clinically significant than ophthalmic ones 6
- Patients with cardiac comorbidities require careful cardiac monitoring in an environment with resuscitation equipment and trained staff 4
- Any tachycardia should be investigated before administering anticholinergic drugs 1
Use with Caution In 1:
- Autonomic neuropathy
- Hyperthyroidism
- Coronary heart disease
- Cardiac arrhythmias
- Hypertension
- Renal disease – the drug is substantially excreted by the kidney, increasing risk of toxic reactions in renal impairment 1
- Hiatal hernia with reflux esophagitis
Elderly Patients 1
- Start at the low end of the dosing range due to greater frequency of decreased hepatic, renal, or cardiac function 1
- Higher risk of mental confusion and excitement 1
- Monitor renal function as elderly patients are more likely to have decreased renal function 1
Pregnancy and Lactation 1
- Pregnancy Category C – no adequate studies in pregnant women; use only if clearly needed 1
- Excreted in human milk – caution should be exercised when administering to nursing women 1
Drug Interactions 1
Additive anticholinergic effects occur when combined with:
- Other antimuscarinics
- Amantadine
- Haloperidol
- Phenothiazines
- MAO inhibitors
- Tricyclic antidepressants
- Some antihistamines
Antacids may interfere with absorption – administer hyoscine before meals and antacids after meals 1
Critical Safety Warnings
Substitution Error Risk 7
- Hyoscine hydrobromide (which crosses the blood-brain barrier) has been mistakenly substituted for hyoscine butylbromide in compounded preparations, leading to severe anticholinergic poisoning with altered mental status, long-lasting memory disturbances, tremor, and photophobia 7
Cardiovascular Monitoring 2
- A documented case report describes hypotension and acute myocardial infarction following intravenous hyoscine injection for colonoscopy premedication 2
- Myocardial ischemia can occur as a sequela of shock status induced by the drug 2
Heat-Related Complications 1
- Decreased sweating can result in heat prostration, fever, or heat stroke 1
- Febrile patients or those exposed to elevated environmental temperatures should use caution 1
Clinical Recommendations for Safe Use
When to Avoid Buscopan 5
- Gastroparesis, diabetic gastrointestinal neuropathy, and chronic constipation – prokinetic agents (metoclopramide, erythromycin, prucalopride) are required instead 5
- Constipation-predominant conditions – anticholinergic effects worsen symptoms 5
Appropriate Use 5
- Short-term or rescue therapy for irritable bowel syndrome with predominant cramping 5
- Abdominal pain in small-intestinal dysmotility when spasm (not hypomotility) is the dominant problem 5
- Acute visceral pain episodes requiring rapid antispasmodic relief 5
Post-Procedural Counseling 4
- Patients who received Buscopan should be counseled to present to an emergency facility if they experience eye pain, redness, decreased vision, nausea, vomiting, or headache 4