Cholinergic agonist (muscarinic)

Bethanechol chloride

Brand names: Myotonine

Bethanechol chloride is the chloride salt of the muscarinic cholinergic agonist bethanechol, used to promote bladder emptying in non-obstructive urinary retention.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 10 to 50 mg three or four times a day (usual adult oral dose)

Route: Oral

Frequency: Three or four times a day

Max: During initial titration, 5 to 10 mg is given and the same amount repeated at hourly intervals until satisfactory response occurs, or until a maximum of 50 mg has been given

US prescribing information (bethanechol chloride tablets, DOSAGE AND ADMINISTRATION): dosage must be individualised, depending on the type and severity of the condition to be treated. Preferably give the drug when the stomach is empty — if taken soon after eating, nausea and vomiting may occur. The minimum effective dose is determined by giving 5 to 10 mg initially and repeating the same amount at hourly intervals until satisfactory response occurs, or until a maximum of 50 mg has been given. The effects of the drug sometimes appear within 30 minutes and are usually maximal within 60 to 90 minutes; drug effects persist for about one hour. If necessary, the effects can be abolished promptly by atropine. Adverse reactions are rare following oral administration but are more common following subcutaneous injection, and are more likely to occur when the dosage is increased. No eMC/UK SPC was available in this bundle — US labelling may differ from UK; clinician to verify against the UK SPC. No paediatric dosing, pregnancy, drug-interaction or renal-adjustment sections were present in the retrieved label.

Dose auto-extracted from US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Hypersensitivity to bethanechol chloride
Hyperthyroidism
Peptic ulcer
Latent or active bronchial asthma
Pronounced bradycardia or hypotension; vasomotor instability
Coronary artery disease
Epilepsy
Parkinsonism
When the strength or integrity of the gastrointestinal or bladder wall is in question, or in the presence of mechanical obstruction — e.g. following recent urinary bladder surgery, gastrointestinal resection and anastomosis, or possible gastrointestinal obstruction
Bladder neck obstruction, spastic gastrointestinal disturbances, acute inflammatory lesions of the gastrointestinal tract, or peritonitis
Marked vagotonia

Side effects

Abdominal cramps or discomfort, colicky pain, nausea and belching, diarrhoea, borborygmi, salivation
A fall in blood pressure with reflex tachycardia; vasomotor response
Flushing producing a feeling of warmth, sensation of heat about the face, sweating
Bronchial constriction; asthmatic attacks
Urinary urgency
Headache, malaise; lacrimation; miosis (seizures reported with causal relationship not established)

Clinical monograph

How it works

It directly stimulates detrusor muscarinic receptors, increasing bladder smooth muscle tone and contraction to aid voiding.

Prescribing in practice

Contraindicated where enhanced cholinergic activity is hazardous, including mechanical urinary or gastrointestinal obstruction, asthma, peptic ulcer disease and certain cardiac disorders.
Cholinergic adverse effects including sweating, salivation, bradycardia, abdominal cramps and bronchospasm may occur.
Atropine should be available as an antidote for severe cholinergic toxicity.

Monitoring

Monitor heart rate, gastrointestinal and respiratory symptoms, and the bladder response to treatment.

Counselling the patient

Report sweating, flushing, abdominal cramps, wheeze or palpitations.
Take on an empty stomach to reduce nausea and vomiting.

Evidence & guidelines

Use reflects established cholinergic pharmacology and the SPC; mechanical obstruction must be excluded before treatment.

Reference: NICE NG123; BAUS; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Pathways