How Do Genitourinary Cholinergics Work?

Genitourinary cholinergics are medications approved by the FDA to treat urinary retention and are also used off-label to treat gastroesophageal reflux disease (GERD). Genitourinary cholinergics stimulate the parasympathetic system to make the bladder detrusor muscle contract adequately to enable effective voiding of the bladder.

Genitourinary cholinergic drugs have effects similar to acetylcholine, a natural chemical (neurotransmitter) in the body that nerve endings secrete to make muscles contract. Genitourinary cholinergics stimulate muscarinic receptors, which are protein molecules on smooth muscle cell membranes that activate muscle contraction.

Genitourinary cholinergics have effects on all 5 types of muscarinic receptors M1-M5, of which M3 receptors are predominantly found in the bladder detrusor muscle. Genitourinary cholinergics also stimulate gastric motility by stimulating M1 receptors in the gastrointestinal tract.

Genitourinary anticholinergics may be administered as oral tablets or subcutaneous injections in the tissue under the skin to treat the following conditions:

FDA-approved:

• Urinary retention, adults

Off-label:

• GERD, adults, and children
• Urinary retention, children

Side effects of genitourinary cholinergics may include the following:

• Abdominal cramps
• Belching
• Borborygmi (stomach rumbling noises) colicky pain
• Bronchial constriction
• Diarrhea
• Flushing
• Increased gastric motility
• Headache
• Hypotension (low blood pressure)
• Lacrimation (eyes watering)
• Miosis (constriction of the eye pupils)
• Nausea
• Vomiting
• Salivation
• Urinary urgency

Information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with your doctor or pharmacist to make sure these drugs do not cause any harm when you take them along with other medicines. Never stop taking your medication and never change your dose or frequency without consulting your doctor.

Generic and brand names of the FDA-approved genitourinary cholinergic drug are:

• bethanechol
• Urecholine