SN instructed patient / caregiver about Bethanechol. Sometimes given orally or subcutaneously to treat urinary retention resulting from general anesthetic, diabetic neuropathy of the bladder, or a side effect of antidepressants or to treat gastrointestinal atony (lack of muscular tone). Adverse reaction are rare following oral administration of Bethanechol, but are more common following subcutaneous injection. Adverse reactions are more likely to occur when dosage is increased. Adverse reactions that have been observed: Body as a Whole: malaise; Digestive: abdominal cramps or discomfort, colicky pain, nausea and belching, diarrhea, borborygmi, salivation; Renal: urinary urgency; Nervous System: headache; Cardiovascular: a fall in blood pressure with reflux tachycardia, vasomotor response; Skin: flushing producing a feeling of warmth, sensation of heat about the face, sweating; Respiratory: bronchial constriction, asthmatic attacks; Special Senses: lacrimation, miosis.