Bethanechol

Description

Bethanechol is an agonist of muscarinic acetylcholine receptors with IC₅₀ values of 1,837, 25, 631, 317, and 393 μM for M_1-5, respectively, in a radioligand binding assay using CHO cells expressing the human receptors. It inhibits M₂-mediated increases in cyclic AMP induced by isoproterenol in isolated guinea pig small intestine (IC₅₀ = 127 μM). Bethanechol increases basal tone of isolated porcine intravesical ureter (EC₅₀ = 4.27 μM). It also induces fluid secretion in the ileum, duodenum, and jejunum of anesthetized rats when administered at a dose of 60 μg/kg. Formulations containing bethanechol have been used to increase urination and improve smooth muscle tone in the gastrointestinal tract.

Chemical Properties

White Solid

Originator

Urecholine CI,MSD,US,1949

Uses

Therapeutic action of Betanechol is based on this action, and it is used for treating postoperational non-obstructive retention of urine and neurogenic bladder atony. Earlier, it was used for treating gastrointestinal illnesses and Alzheimer’s disease.

Uses

A selective muscarinic receptor stimulant, used to treat cerebral palsy.

Uses

cholinergic

Definition

ChEBI: The chloride salt of bethanechol. A slowly hydrolysed muscarinic agonist with no nicotinic effects, it is used to increase smooth muscle tone, as in the gastrointestinal tract following abdominal surgery, treatment of gastro-oesophageal reflux disease, and as an alternative to catheterisation in the treatment of non-obstructive urinary retention.

Manufacturing Process

About 3 grams of β-methylcholine chloride are stirred at room temperature with an excess of phosgene dissolved in 50 grams of chloroform, for about 2 hours. Excess phosgene and hydrochloric acid are removed by distillation under vacuo. Additional chloroform is added to the syrup and the mixture is poured into excess ammonia dissolved in chloroform and cooled in solid carbon dioxide-acetone. The solid is filtered and extracted with hot absolute alcohol. The solid in the alcohol is precipitated with ether, filtered, and recrystallized from isopropanol. The carbaminoyl-β-methylcholine chloride obtained has a melting point of about 220°C.

brand name

Duvoid (WellSpring); Myotonachol (Glenwood); Urecholine (Odyssey).

Therapeutic Function

Cholinergic

General Description

Bethanechol, β-methylcholinechloride carbamate, (2-hydroxypropyl)trimethylammoniumchloride carbamate, carbamylmethylcholinechloride (Urecholine), is nonspecific in its action on muscarinicreceptor subtypes but appears to be more effective ateliciting pharmacological action of M3 receptors. It haspharmacological properties similar to those of methacholine.Both are esters of β-methylcholine and have feeblenicotinic activity. Bethanechol is inactivated more slowlyby AChE in vivo than is methacholine. It is a carbamyl esterand is expected to have stability in aqueous solutions similarto that of carbachol.

Hazard

Headache, flushing, gastrointestinal distress, diarrhea, hypotension, excessive salivation, sweating, hypersensitivity.

Mechanism of action

Bentanechol is a drug, which has structurally unique qualities of both methacholine and carbachol, i.e. it contains both β-methyl and carbamate functional groups, and quite logically exhibits pharmacological properties of both the drugs. It is resistant to hydrolysis by cholinesterases and has a very minor effect on nicotinic receptors of the autonomic ganglia and neuromuscular junctions. Betanechol has more of a selective action on muscarinic receptors of the gastrointestinal tract and the bladder than do other cholinic esters.

Clinical Use

The main use of bethanechol chloride is in the relief ofurinary retention and abdominal distention after surgery.The drug is used orally and by subcutaneous injection. Itmust never be administered by intramuscular or intravenousinjection because of the danger from cholinergic overstimulationand loss of selective action. Proper administration ofthe drug is associated with low toxicity and no serious sideeffects. Bethanechol chloride should be used with caution inasthmatic patients; when used for glaucoma, it producesfrontal headaches from the constriction of the sphinctermuscle in the eye and from ciliary muscle spasms. Its durationof action is 1 hour.

Synthesis

Betanechol, 2-carbamoyloxy-1-(N,N,N-trimethyl)propyl ammonium chloride (13.1.8), is made by either the subsequent reaction of 1-(N,N,N-trimethylammonium) propan-2-ol with phosgene, followed by ammonia, or by a completely analogous synthesis of carbachol by the reaction of 1-chloro-2-propanol with phosgene followed by consequent reactions with ammonia, and then with trimethylamine, giving betanechol (13.1.8) [14,15].

Veterinary Drugs and Treatments

In veterinary medicine, bethanechol is used primarily to stimulate bladder contractions in small animals. It also can be used as an esophageal or general GI stimulant, although metoclopramide and/ or neostigmine have largely supplanted it for these uses.