ADVERSE REACTIONS Adverse reactions are rare following oral administration of bethanechol chloride, but are more common following subcutaneous injection. Adverse reactions are more likely to occur when dosage is increased. The following adverse reactions have been observed: Body as a Whole: Malaise. Cardiovascular: Fall in blood pressure with reflex tachycardia, vasomotor response. Digestive: Colicky pain, abdominal cramps or discomfort, diarrhea, nausea and belching, salivation, and borborygmi. Skin: Flushing, producing a feeling of warmth; sensation of heat about the face; sweating. Respiratory: Asthmatic attacks and bronchial constriction. Nervous System: Headache. Renal: Urinary urgency. Special Senses: Lacrimation, miosis. Causal Relationship Unknown: The following adverse reactions have been reported, and a causal relationship to therapy with bethanechol chloride has not been established: Body as a Whole: Malaise. Nervous System: Seizures.