Adult Intravenous Dose of Hyoscine Butylbromide
The recommended adult intravenous dose of hyoscine butylbromide is 20 mg administered as a single slow IV injection.
Standard Dosing
The most reliable dosing information comes from the FDA-approved drug label 1, which specifies 0.3 mg/kg body weight administered slowly IV as a single injection. For practical clinical use, this translates to:
- 20 mg IV (standard adult dose)
- Administered as a slow intravenous injection
- Can be repeated if necessary
Clinical Context and Usage
Hyoscine butylbromide (also known as Buscopan) is an anticholinergic antispasmodic agent used across multiple clinical scenarios:
Anesthesia/Procedural Use
In the context of awake tracheal intubation, hyoscine hydrobromide (a related compound) is used as an antisialogogue at doses of 0.2-0.6 mg IM (administered 30-60 minutes pre-procedure) or 5-10 minutes IV, though this has longer-lasting systemic effects than other antisialogues 2.
Gastrointestinal Applications
Multiple studies have evaluated 20 mg IV as the standard dose:
- Colonoscopy: 20 mg IV administered at withdrawal to potentially improve mucosal visualization 3, 4
- Acute gastroenteritis: 20 mg IV for abdominal cramping pain 5
- Gynecological procedures: 20 mg IV for pain reduction during manual vacuum aspiration 6
Imaging Studies
For pelvic MRI, 20 mg IV hyoscine butylbromide significantly improves image quality and lesion visualization by reducing bowel peristalsis 7.
Important Clinical Considerations
Onset and Duration:
- Onset: 5-10 minutes when given IV
- Duration: Approximately 4 hours of effect
- Peak anticholinergic effects occur within the first hour
Common Side Effects:
- Pupillary dilation (transient, typically resolves within 4-24 hours)
- Dry mouth
- Tachycardia (usually mild and transient)
- Reduced bowel sounds (expected therapeutic effect)
Contraindications to Consider:
- Narrow-angle glaucoma
- Myasthenia gravis
- Megacolon
- Obstructive uropathy
- Tachyarrhythmias
Dosing Pitfalls
Do not confuse hyoscine butylbromide with hyoscine hydrobromide—these are different compounds with different dosing regimens. The butylbromide form has limited CNS penetration due to its quaternary ammonium structure, making it safer with fewer central side effects.
Avoid rapid IV push: The drug should be administered as a slow IV injection to minimize cardiovascular effects, particularly transient tachycardia.
Repeat dosing: While the FDA label describes single-dose administration, clinical practice may involve repeat dosing. The safety data from veterinary studies 1 showed that doses up to 10 times the recommended amount were well-tolerated, though this should not guide human dosing. If repeat dosing is needed, allow adequate time (at least 4-6 hours) between doses and monitor for cumulative anticholinergic effects.
Dose adjustment: Unlike many medications, hyoscine butylbromide does not require dose reduction in elderly patients based on age alone, though clinical judgment regarding anticholinergic burden in this population is warranted.