Hyoscine hydrobromide
Class: anticholinergic – antisecretory
Indications (NB some may be unlicensed): premedication for sedation/amnesia, nausea/vomiting from motion sickness, excessive respiratory secretions
Contraindications/cautions: elderly, urinary retention, cardiac disease, glaucoma
Adverse reactions: common: dry mouth, tachycardia, hypotension (especially with morphine); less common: urinary retention, visual problems, dizziness, constipation, drowsiness, hallucinations (commoner in the elderly)
Interactions:
- additive anticholinergic effects (e.g. dry mouth, urinary retention) may occur with other drugs which have anticholinergic effects e.g. cyclizine, amitriptyline, phenothiazines (e.g. chlorpromazine)
- decreased clinical effect (prokinetic effects) of metoclopramide/domperidone may occur with concomitant hyoscine
| Dosing: | |
|---|---|
| oral: | not available |
| subcut | (as the hydrobromide): 0.4 to 2.4 mg/24 hours (usually 0.8 to 1.2 mg stat) |
| rectal: | not available |
| transdermal patch: | 1 patch (1.5 mg)/72 hours (behind the ear) |
Syringe driver: see syringe driver compatibility chart
Mechanism of action: blocks cholinergic receptors in CNS and the gastrointestinal tract
Peak response: im: 1 to 2 hours (antisecretory)
Duration: im: 8 hours
Notes:
- thought to cross the blood brain barrier more easily then hyoscine butylbromide
- risk of confusion in the elderly is high
- may be particularly useful in nausea and vomiting related to motion
- has a transdermal preparation – funded under Special Authority