Hyoscine Butylbromide

How it works

It blocks muscarinic receptors on smooth muscle, relaxing spasm; it crosses the blood-brain barrier poorly, so central effects are limited.

Prescribing in practice

• Given intravenously it can cause serious tachycardia and hypotension — use caution and have monitoring in patients with cardiac disease (MHRA).
• Antimuscarinic cautions apply — avoid in narrow-angle glaucoma, significant bladder-outflow obstruction and gastrointestinal obstruction.
• Oral absorption is low, so the oral form mainly acts locally in the gut.

Monitoring

For intravenous use, monitor heart rate and blood pressure, especially in cardiac disease.

Counselling the patient

• It can cause dry mouth and blurred vision.
• Report difficulty passing urine or eye pain.

Evidence & guidelines

An antispasmodic for smooth-muscle colic and for secretions in palliative care, with an MHRA caution about intravenous use in cardiac disease.