Intramuscular Buscopan (Hyoscine Butylbromide) Administration
For intramuscular administration in adults, Buscopan (hyoscine butylbromide) is given at a dose of 20 mg (1 mL of 20 mg/mL solution), which can be repeated as needed for severe abdominal cramping and gastrointestinal spasms. 1, 2
Indications for IM Buscopan
- Abdominal pain associated with gastrointestinal cramping and spasms where oral administration is not feasible or effective 1, 3
- Severe or refractory abdominal pain requiring parenteral administration 3
- Intestinal dysmotility with significant cramping 1
- IM preparations may be more effective than oral forms due to poor oral bioavailability (<1%) of hyoscine butylbromide 2
Dosing Specifications
- Standard adult IM dose: 20 mg (1 mL) as a single injection 1, 2
- Can be repeated based on clinical response and symptom severity 2
- IM route provides better systemic availability compared to oral administration, which has bioavailability <1% 2
- The drug has high tissue affinity for muscarinic receptors at the site of action in the intestine 2
Absolute Contraindications
Cardiac conditions requiring extreme caution or avoidance:
- Tachycardia - Buscopan is contraindicated according to product monograph 4
- Angina pectoris - contraindicated per product labeling 4
- Cardiac failure - contraindicated per product labeling 4
Other absolute contraindications:
- Prostatic hypertrophy with urinary retention - contraindicated per product monograph 4
Critical Precautions and Monitoring
Cardiac monitoring is essential:
- Patients with any cardiac comorbidities require careful cardiac monitoring during and after administration 3, 4
- Cardiac complications are more clinically significant than ophthalmic complications 3
- Administration should only occur in environments where resuscitation equipment and appropriately trained staff are readily available 4
Risk-benefit assessment required:
- In patients with contraindicated conditions, use only when potential benefits clearly outweigh risks 4
- This requires explicit clinical judgment on a case-by-case basis 4
Mechanism and Clinical Pharmacology
- Hyoscine butylbromide is a quaternary ammonium antimuscarinic agent that blocks muscarinic receptors on GI smooth muscle 2, 5
- It also blocks nicotinic acetylcholine receptors, producing a ganglion-blocking effect that contributes to spasmolytic activity 2, 6
- The drug does not cross the blood-brain barrier due to its quaternary structure, minimizing central nervous system effects 2
- High tissue affinity for muscarinic receptors allows local spasmolytic effect despite low systemic bioavailability 2
Post-Administration Counseling
Patients should be instructed to seek emergency care if they develop:
- Eye pain or redness 4
- Decreased vision 4
- Nausea and vomiting (in context of visual symptoms) 4
- Severe headache (in context of visual symptoms) 4
These symptoms could indicate acute angle-closure glaucoma, though this risk is lower than cardiac complications 4.
Common Pitfalls to Avoid
- Do not use in patients with documented tachycardia, angina, or heart failure without explicit consideration that benefits outweigh substantial risks 4
- Do not assume glaucoma history is the primary concern - cardiac monitoring takes precedence 3, 4
- Do not use IM route when oral administration is adequate - reserve parenteral route for severe or refractory cases 3
- Ensure resuscitation capabilities are immediately available before administration in any patient with cardiac risk factors 4