[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Muscarinic (cholinergic) agonists](https://durgical.com/en/pharmacology/classes/muscarinic-agonists/) › Bethanechol [Pharmacology](https://durgical.com/en/pharmacology/) · [Muscarinic (cholinergic) agonists](https://durgical.com/en/pharmacology/classes/muscarinic-agonists/) # Bethanechol A choline ester that contracts the bladder to treat urinary retention when nothing is blocking the outflow. Updated 2026-11-01 - Class: [Muscarinic (cholinergic) agonists](https://durgical.com/en/pharmacology/classes/muscarinic-agonists/) - Receptor: Muscarinic M3 receptor of the bladder detrusor - ATC code: N07AB02 ◎**Muscarinic M3 receptor of the bladder detrusor**Bethanechol ⓘ No structure of bethanechol bound to its receptor exists. The figure shows iperoxo, a potent research agonist, in the acetylcholine (orthosteric) pocket of the active human M3 muscarinic receptor, the subtype on glands, the eye and the bladder that bethanechol stimulates. **Target in 3D:** Muscarinic M3 receptor of the bladder detrusor. PDB structure 8E9Z (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/8E9Z) · Drag to rotate · pinch to zoom ## Mechanism of action Bethanechol is a synthetic choline ester that cholinesterase does not destroy, so it lasts longer than acetylcholine. It stimulates muscarinic receptors with little nicotinic effect: it raises the tone of the detrusor muscle enough to start urination and empty the bladder, and it increases gut tone and peristalsis. Its charged quaternary group keeps it out of the brain. - Resists breakdown by cholinesterase - Activates muscarinic receptors of the detrusor - Bladder contracts and empties - Also increases gut tone and peristalsis ## Pharmacokinetics **Absorption** Taken by mouth, on an empty stomach to reduce nausea **Distribution** Does not cross the blood-brain barrier **Metabolism** Not destroyed by cholinesterase ## Indications - Acute postoperative and postpartum urinary retention without obstruction [Acute urinary retention →](https://durgical.com/en/conditions/acute-urinary-retention/) - Neurogenic atony of the bladder with retention [Neurogenic bladder →](https://durgical.com/en/conditions/neurogenic-bladder/) ## Adverse effects ### Common - Abdominal cramps, colicky pain, nausea, belching and diarrhoea - Salivation, sweating and flushing - Urinary urgency - Headache ### Serious (rare, important) - Bronchospasm in asthma - Low blood pressure and slow heart rate - Atrial fibrillation in hyperthyroidism (class) ## Contraindications - Mechanical obstruction of the bladder outlet or gut, or doubtful integrity of the bladder or gut wall (for example after recent surgery) - Asthma, latent or active - Peptic ulcer - Hyperthyroidism - Marked bradycardia, low blood pressure, vasomotor instability or coronary disease - Epilepsy and parkinsonism ## Key interactions **Ganglion-blocking drugs** Critical fall in blood pressure, usually preceded by severe abdominal symptoms **Cholinesterase inhibitors (donepezil, galantamine)** Additive cholinergic effects **Antimuscarinic drugs** Opposite effects ## What is monitored - Urine output and post-void residual volume - Blood pressure and heart rate - Breathing in people with lung disease ## Administration and safety - Given on an empty stomach to reduce nausea and vomiting - Obstruction is ruled out before starting - Atropine is the specific antidote and is kept available ## Nursing care - Have a bedpan or toilet close: urge to void can come quickly - Measure intake, output and bladder volume - Watch for flushing, sweating, cramps and dizziness on standing ## Pregnancy and breastfeeding Safety in pregnancy is not established; it is used only if clearly needed. ## Memory aid BETHANEchol = «Bladder Emptying Tool»: but only if the exit is open. ## Test yourself Think of the answer, then tap the question to see it. ## Why does bethanechol last longer than acetylcholine? It is a choline ester that is not destroyed by cholinesterase. ## Which kind of urinary retention can bethanechol treat? Non-obstructive (functional) retention, for example after surgery or childbirth, or neurogenic atony. ## Which respiratory disease is a contraindication to bethanechol? Asthma, latent or active: muscarinic stimulation causes bronchospasm. [Add to my cards (3)](https://durgical.app/estudiar/?add=/en/pharmacology/bethanechol/) ## Related drugs - [Pilocarpine](https://durgical.com/en/pharmacology/pilocarpine/) - [Methacholine](https://durgical.com/en/pharmacology/methacholine/) ## Related conditions - [Acute urinary retention](https://durgical.com/en/conditions/acute-urinary-retention/) - [Neurogenic bladder](https://durgical.com/en/conditions/neurogenic-bladder/) [← Back to the class: Muscarinic (cholinergic) agonists](https://durgical.com/en/pharmacology/classes/muscarinic-agonists/) Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given. Sources: [DailyMed - BETHANECHOL CHLORIDE tablet](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=80393410-dd51-4cac-b27c-50ece00cca37) (DailyMed (U.S. National Library of Medicine), 2026); [Bethanechol: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a682849.html) (MedlinePlus (U.S. National Library of Medicine), 2026); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 11 (McGraw Hill, 2023); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=N07AB02) (WHO Collaborating Centre for Drug Statistics Methodology, 2026). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/pharmacology/bethanechol/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/bethanechol/