Urinary retention.

Due to stimulation of the parasympathetic nervous system, bethanechol increases bladder muscle tone causing contractions which initiate urination. Bethanechol also stimulates gastric motility, increases gastric tone and may restore peristalsis.(UTD)

asthma
bradycardia, hypotension/vasomotor instability/vagotonia
compromised integrity of gastrointestinal or bladder wall
coronary artery disease
epilepsy
gastrointestinal inflammation, spasms, peritonitis
gastrointestinal or bladder surgery, resection, obstruction
hypersensitivity to bethanechol or components
hyperthyroidism
Parkinsonism
peptic ulcer.

C (FDA) B2 (AUS)

Infant risk cannot be ruled out.(MDX)

Common:
Dermatologic: Flushing
Gastrointestinal: Abdominal cramps, Diarrhea
Renal: Urgent desire to urinate
Serious:
Neurologic: Seizure
Respiratory: Acute exacerbation of asthma

Urinary retention:
initial, 5 to 10 mg ORALLY repeated hourly until satisfactory response, MAX 50 mg; usual dose range, 10 to 50 mg ORALLY 3 or 4 times daily
initial, 0.5 mL (2.575 mg) SC at 15-30 min intervals until satisfactory response, MAX 4 doses; maintenance, 1 mL (5.15 mg) SC, 3-4 times daily.

not FDA approved in pediatric patients