Cholinergic therapy (GU): Nursing pharmacology

Urinary cholinergic agents are a group of medications that can be used to treat urinary retention, which refers to the inability of a client to empty their bladder completely, or sometimes even at all. The most commonly used cholinergic agent is bethanechol.

Bethanechol can be administered orally, and it works on the bladder as a muscarinic agonist, ultimately stimulating the contraction of the detrusor muscle, which is a wall of smooth muscle that surrounds the bladder.

Unfortunately, clients taking a cholinergic agent may experience increased urinary frequency and urgency. Additional side effects commonly associated with cholinergic agents include headache, dizziness, blurred vision, and lacrimation.

Clients may also develop a skin rash, urticaria, flushing, and diaphoresis.

In addition, clients may experience hypersalivation, abdominal cramps, nausea, vomiting, diarrhea, and fecal incontinence. Some clients may also have bronchoconstriction, which can lead to dyspnea or asthma.

The most severe side effects of cholinergic agents include hypotension, bradycardia, as well as reflex tachycardia, and even arrhythmias or cardiac arrest. Finally, cholinergic toxicity can be managed with the antidote atropine, which blocks muscarinic receptors.

As far as contraindications go, cholinergic agents should not be given to clients with genitourinary or gastrointestinal obstruction, as well as those with severe hypotension, bradycardia, or coronary artery disease.

Additional contraindications include asthma or COPD, as well as parkinsonism or seizures.

Finally, cholinergic agents should be used with caution during pregnancy and breastfeeding, as well as in children younger than 8 years, and in clients with hypertension.

Now, when a client with urinary retention is prescribed a cholinergic agent like bethanechol, first ask them about their urinary symptoms; this includes hesitancy, an intermittent or slow stream of urine, and if they feel their bladder isn’t quite empty after using the bathroom.

Then, assess your client’s vital signs, fluid intake and output, and assess their abdomen for bladder distention. Lastly, review recent laboratory test results, including urinalysis and culture, as well as results of diagnostic tests such as bladder ultrasound and measurement of post-void residual.