URECHOLINE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for URECHOLINE (URECHOLINE).
Bethanechol is a synthetic choline ester that directly stimulates muscarinic acetylcholine receptors, primarily M2 and M3 subtypes, leading to increased gastrointestinal motility, bladder contraction, and other parasympathetic effects. It has minimal nicotinic activity.
| Metabolism | Primarily metabolized by plasma and tissue esterases via hydrolysis; negligible hepatic metabolism. |
| Excretion | Primarily renal excretion of unchanged drug and metabolites; approximately 50-60% excreted in urine within 24 hours, with negligible biliary or fecal elimination. |
| Half-life | Terminal elimination half-life is approximately 1.5-2 hours. Due to its short half-life, continuous or frequent dosing is required for sustained cholinergic effects. |
| Protein binding | Minimal (<5%) binding to plasma proteins, primarily albumin. |
| Volume of Distribution | Approximately 0.3-0.5 L/kg, indicating distribution primarily into extracellular fluid with limited tissue penetration. |
| Bioavailability | Oral: 10-20% due to extensive first-pass metabolism; Subcutaneous: near 100% bioavailable. |
| Onset of Action | Oral: 30-90 minutes; Subcutaneous: 5-15 minutes. Intravenous administration is contraindicated due to risk of severe cholinergic crisis. |
| Duration of Action | Oral: 4-6 hours; Subcutaneous: 2-4 hours. Duration may be dose-dependent and shorter in patients with rapid gastrointestinal transit. |
| Molecular Weight | 197.26 |
10-50 mg orally two to four times daily; alternatively, 5 mg subcutaneously three to four times daily. Maximum oral dose: 200 mg daily.
| Dosage form | TABLET |
| Renal impairment | Contraindicated in patients with significant renal impairment (CrCl < 30 mL/min). Use with caution in mild to moderate impairment, with dose reduction as needed. |
| Liver impairment | No specific adjustment recommended for Child-Pugh classification; use with caution in severe hepatic impairment. |
| Pediatric use | Safety and efficacy not established for children under 8 years. For older children, oral dose of 0.6 mg/kg three times daily, or subcutaneous dose of 0.15 mg/kg three to four times daily. Maximum single dose: 5 mg. |
| Geriatric use | Initiate at low end of dosing range (e.g., 5-10 mg orally) due to increased sensitivity to cholinergic effects and risk of bradycardia, hypotension, and falls. Titrate slowly based on response and tolerability. |
| 1st trimester | Bethanechol is a quaternary ammonium compound with limited placental transfer; however, safety in human pregnancy is not established. Animal studies are insufficient. Use only if clearly needed and benefit outweighs risk. |
| 2nd trimester | Same as T1: limited data; may be used with caution if required. |
| 3rd trimester | Same as T1: may stimulate uterine contractions if given near term? No definitive evidence; avoid if possible. |
Clinical note
Comprehensive clinical and safety monograph for URECHOLINE (URECHOLINE).
| Placental transfer | Minimal; bethanechol is a quaternary ammonium compound with limited lipid solubility and low placental transfer. No quantitative human data but expected to cross poorly. |
| Breastfeeding | Bethanechol is excreted into breast milk in small amounts due to its quaternary ammonium structure; theoretical risk of cholinergic effects in infants (e.g., diarrhea, bradycardia). Use with caution, monitor infant for adverse effects, or consider alternative therapy. |
■ FDA Black Box Warning
None.
| Serious Effects |
Hypersensitivity to bethanechol or any componentMechanical gastrointestinal or urinary obstructionHyperthyroidismPeptic ulcer diseaseAsthmaBradycardia or hypotensionCoronary artery diseaseEpilepsyParkinsonism
| Precautions | Risk of severe cholinergic adverse effects, including hypotension, bradycardia, and bronchospasm., Use with caution in patients with epilepsy, hyperthyroidism, asthma, coronary artery disease, or peptic ulcer disease., May exacerbate urinary obstruction if anatomical obstruction is present., Administer subcutaneously only; not for intramuscular or intravenous use (risk of severe cholinergic crisis). |
| Food/Dietary | No specific food interactions; however, take on an empty stomach to avoid nausea and vomiting. Avoid alcohol as it may exacerbate side effects such as dizziness or hypotension. |
Loading safety data…
| Lactation Rating | L3 - Moderately Safe |
| Teratogenic Risk | Pregnancy Category C. First trimester: No adequate human studies; animal studies not available. Second and third trimesters: Potential to induce uterine hypertonicity and fetal bradycardia if used near term. Avoid use during pregnancy unless clearly necessary. |
| Fetal Monitoring | Monitor maternal heart rate, blood pressure, and signs of cholinergic excess. Fetal heart rate monitoring if used near term. |
| Fertility Effects | No data on effects on human fertility. Animal studies not available. |
| Clinical Pearls | Urecholine (bethanechol) is a parasympathomimetic used primarily for non-obstructive urinary retention. Avoid use in patients with mechanical GI or GU obstruction, hyperthyroidism, peptic ulcer disease, asthma, bradycardia, or hypotension. Administer on an empty stomach (1 hour before or 2 hours after meals) to minimize nausea and vomiting. Monitor for signs of cholinergic crisis (e.g., excessive salivation, sweating, bradycardia). Atropine is the antidote for overdose. |
| Patient Advice | Take this medication on an empty stomach at least 1 hour before or 2 hours after meals to reduce stomach upset. · Do not crush or chew the tablets; swallow whole with water. · You may experience increased sweating, salivation, or urge to urinate shortly after taking the dose. · Avoid driving or operating heavy machinery until you know how this medication affects you, as it may cause dizziness or blurred vision. · Contact your healthcare provider immediately if you experience slow heart rate, difficulty breathing, severe abdominal pain, or signs of an allergic reaction. |