Actions and Spectrum: 

• bethanechol is a medication that acts as a cholinergic agonist, stimulating the receptors that respond to the neurotransmitter acetylcholine. Specifically, bethanechol acts on muscarinic receptors, which are found in smooth muscle tissue, glands, and the central nervous system. 
• bethanechol’s primary mechanism of action stimulates the parasympathetic nervous system, which regulates many bodily functions, including digestion, urination, and heart rate. By activating muscarinic receptors, bethanechol can cause increased contraction of smooth muscle in the bladder and gastrointestinal tract, leading to increased urinary output and enhanced gastrointestinal motility. 
• bethanechol has a relatively narrow spectrum of activity and is primarily used to treat urinary retention or dysfunction caused by a lack of bladder contractility. It may also stimulate gastrointestinal motility in patients with certain conditions, such as gastroesophageal reflux disease or postoperative ileus. bethanechol is impractical for treating urinary retention caused by an obstruction, such as an enlarged prostate or urethral stricture. 

DRUG INTERACTION

Contraindicated  

Serious Use Alternative  

Monitor Closely  

Minor  

Frequency not defined 

Belching 

Bronchial constriction 

Flushing 

Headache 

Lacrimation 

Nausea 

Salivation 

Abdominal cramps 

Borborygmi colicky pain 

Diarrhea 

Increased gastric motility 

Hypotension 

Miosis 

Vomiting 

Urinary urgency 

Contraindications/caution: 

Contraindications: 

• Hypersensitivity to bethanechol or its components: Patients allergic to bethanechol or its ingredients should not use this medication. 
• Asthma: bethanechol can cause bronchial constriction, worsening asthma symptoms in patients with this condition. 
• Peptic ulcer disease: bethanechol can increase gastric acid secretion and worsen the disease. 
• Intestinal or urinary tract obstruction: bethanechol can increase smooth muscle contractions, worsening urinary or gastrointestinal tract obstruction. 
• Hyperthyroidism: bethanechol can worsen symptoms of hyperthyroidism, including tachycardia, hypertension, and anxiety. 
• Epilepsy: bethanechol can lower the seizure threshold and increase the risk of seizures in patients with epilepsy. 
• Parkinson’s disease: bethanechol can worsen symptoms of Parkinson’s disease, including tremors and rigidity.

Caution: 

• Cardiovascular disease: bethanechol can cause bradycardia (slow heart rate) and hypotension (low blood pressure), which can be dangerous in patients with pre-existing cardiovascular disease. 
• Chronic obstructive pulmonary disease (COPD): bethanechol can cause bronchial constriction, worsening symptoms in COPD patients. 
• Gastrointestinal disorders: bethanechol can increase gastric acid secretion and exacerbate symptoms in patients with gastrointestinal disorders, such as gastroesophageal reflux. 
• Urinary tract disorders: bethanechol can increase urinary frequency and urgency, which can be problematic in patients with urinary incontinence or other disorders. 
• Pregnancy and breast-feeding: bethanechol should only be used during pregnancy or breastfeeding if the benefits outweigh the risks, as its safety in these populations has not been well established. 
• Renal or hepatic impairment: bethanechol is primarily eliminated by the kidneys and liver, so caution should be used when administering this medication to patients with impaired renal or hepatic function. 

Pregnancy consideration: C 

Lactation: Excretion of the drug in human breast milk is unknown 

Pregnancy category: 

Category A: well-controlled and Satisfactory studies show no risk to the fetus in the first or later trimester.   

Category B: there was no evidence of risk to the fetus in animal studies, and there were not enough studies on pregnant women. 

Category C: there was evidence of risk of adverse effects in animal reproduction studies, and no adequate evidence in human studies must take care of potential risks in pregnant women.    

Category D: adequate data available with sufficient evidence of human fetal risk from various platforms, but despite the potential risk, and used only in emergency cases for potential benefits.    

Category X: Drugs listed in this category outweigh the risks over benefits. Hence these categories of drugs need to be avoided by pregnant women.    

Category N: There is no data available for the drug under this category 

Pharmacology: 

bethanechol is a cholinergic agonist that acts primarily on muscarinic receptors. When administered, bethanechol binds to and activates muscarinic receptors in various smooth muscle tissues, including the bladder and gastrointestinal tract. This leads to increased contractions and enhanced motility in these organs 

Pharmacodynamics: 

The pharmacodynamics of bethanechol is based on its ability to activate muscarinic receptors in various smooth muscle tissues. When bethanechol binds to muscarinic receptors, it causes the following effects: 

• Increased contraction of smooth muscle: bethanechol stimulates muscarinic receptors in the bladder and gastrointestinal tract, leading to increased contractions of these organs. 
• Increased glandular secretion: bethanechol stimulates muscarinic receptors in the salivary and sweat glands, leading to increased secretion of saliva and sweat. 
• Cardiovascular effects: bethanechol can cause bradycardia (slow heart rate) and hypotension (low blood pressure) due to its effects on muscarinic receptors in the heart and blood vessels. 
• CNS effects: Although bethanechol does not cross the blood-brain barrier, it can still cause some CNS effects, such as increased arousal and anxiety. 

Pharmacokinetics: 

Absorption 

bethanechol is well-absorbed after oral administration, with peak plasma concentrations reached within 60-90 minutes. However, its bioavailability is low, ranging from 5-25%, due to extensive first-pass metabolism in the liver. 

Distribution 

bethanechol has a low volume of distribution, indicating that it is primarily confined to the extracellular fluid. It does not readily cross the blood-brain barrier. 

Metabolism 

Acetylcholinesterase primarily metabolizes bethanechol in the liver, hydrolyzing it to its inactive metabolite, choline. It has a relatively short half-life of approximately 1.5 hours. 

Elimination and Excretion 

bethanechol and its metabolites are primarily excreted in the urine, with approximately 50-60% of a dose eliminated within 24 hours. It is not known to undergo significant enterohepatic circulation. 

Administration: 

Oral administration: 

Administer the medication two hours before or after a meal 

Patient information leaflet 

Generic Name: bethanechol 

Pronounced: [ be-THAN-e-chol ] 

Why do we use bethanechol? 

bethanechol is primarily used to treat urinary retention and certain gastrointestinal motility disorders. Here are some of the specific uses of bethanechol: 

• Urinary retention: bethanechol treats acute and chronic urinary retention, which is the inability to empty the bladder. It works by increasing the contraction of the detrusor muscle in the bladder, which helps to expel urine. 
• Gastrointestinal motility disorders: bethanechol is sometimes used to treat certain gastrointestinal motility disorders, such as gastroesophageal reflux disease (GERD) and delayed gastric emptying. It works by increasing smooth muscle contraction in the gastrointestinal tract, which promotes motility and emptying of the stomach and intestines. 
• Diagnostic purposes: bethanechol can also be used as a diagnostic tool to assess bladder function in patients with suspected neurogenic bladder dysfunction.