Brand name : UROTONE (Bethanechol Chloride, Duvoid, Myotonachol, Urecholine)

DESCRIPTION
Bethanechol Chloride is a choline ester quaternary ammonium salt. As a parasympathomimetic agent, it has little nicotinic activity and its actions are predominantly muscarinic actions of acetyl choline. Since it is not hydrolysed by choline esterases, its actions are more prolonged than those of acetyl choline. It is used as an alternative to catheterisation in the treatment of urinary retention.

INDICATIONS
Nonobstructive urinary retention and retention due to neurogenic bladder; treatment and prevention of bladder dysfunction caused by phenothiazines; diagnosis of flaccid or atonic neurogenic bladder; gastroesophageal reflux.

Pregnancy Risk Factor C

CONTRAINDICATIONS
Hypersensitivity to bethanechol; do not use in patients with mechanical obstruction of the GI or GU tract or when the strength or integrity of the GI or bladder wall is in question. It is also contraindicated in patients with hyperthyroidism, peptic ulcer disease, epilepsy, obstructive pulmonary disease, bradycardia, vasomotor instability, atrioventricular conduction defects, hypotension, or parkinsonism; contraindicated for I.M. or I.V. use due to a likely severe cholinergic reaction.

WARNINGS/PRECAUTIONS
Potential for reflux infection if the sphincter fails to relax as bethanechol contracts the bladder; use with caution when administering to nursing women, as it is unknown if the drug is excreted in breast milk; safety and efficacy in children <5 years of age have not been established; syringe containing atropine should be readily available for treatment of serious side effects.

ADVERSE REACTIONS
Oral: <1%:
Cardiovascular: Hypotension, cardiac arrest, flushed skin
Gastrointestinal: Abdominal cramps, diarrhea, nausea, vomiting
Respiratory: Bronchial constriction
Miscellaneous: Sweating, salivation, vasomotor response
Subcutaneous: 1% to 10%:
Cardiovascular: Hypotension, cardiac arrest, flushed skin
Gastrointestinal: Abdominal cramps, diarrhea, nausea, vomiting
Respiratory: Bronchial constriction
Miscellaneous: Sweating, salivation, vasomotor response

DRUG INTERACTIONS
Decreased effect: Procainamide, quinidine Increased toxicity: Bethanechol and ganglionic blockers ® critical fall in blood pressure; cholinergic drugs or anticholinesterase agents

OVERDOSAGE/TOXICOLOGY
Symptoms of overdose include nausea, vomiting, abdominal cramps, diarrhea, involuntary defecation, flushed skin, hypotension, bronchospasm Atropine is the treatment of choice for intoxications manifesting with significant muscarinic symptoms; atropine I.V. 0.6 mg every 3-60 minutes (or 0.01 mg/kg I.V. every 2 hours if needed for children) should be repeated to control symptoms and then continued as needed for 1-2 days following the acute ingestion. Epinephrine 0.1-1 mg S.C. may be useful in reversing severe cardiovascular or pulmonary sequel.

MECHANISM OF ACTION
Stimulates cholinergic receptors in the smooth muscle of the urinary bladder and gastrointestinal tract resulting in increased peristalsis, increased GI and pancreatic secretions, bladder muscle contraction, and increased ureteral peristaltic waves

PHARMACODYNAMICS/KINETICS
Onset of action: Oral: 30-90 minutes
S.C.: 5-15 minutes
Duration of action:
Oral: Up to 6 hours
S.C.: 2 hours
Absorption: Oral: Variable .

USUAL DOSAGE I.V.
Children:
Oral: Abdominal distention or urinary retention: 0.6 mg/kg/day divided 3-4 times/day Gastroesophageal reflux: 0.1-0.2 mg/kg/dose given 30 minutes to 1 hour before each meal to a maximum of 4 times/day
S.C.: 0.15-0.2 mg/kg/day divided 3-4 times/day
Adults:
Oral: 10-50 mg 2-4 times/day S.C.: 2.5-5 mg 3-4 times/day, up to 7.5-10 mg every 4 hours for neurogenic bladder

PATIENT INFORMATION
Oral should be taken 1 hour before meals or 2 hours after meals to avoid nausea or vomiting; may cause abdominal discomfort, salivation, sweating or flushing - notify physician if these symptoms become pronounced; rise slowly from sitting/lying down.