247 - Bethanechol induced dysrhythmias, an unexpected cause for anoxic brain injury

63-year-old male who underwent an acute comprehensive inpatient rehabilitation course after sustaining a STEMI and left MCA stroke complicated by urinary retention and new onset Atrial fibrillation. After discharge, he was seen by urology for continued urinary retention and was started on bethanechol chloride 25 mg BID. Two weeks later, patient presented to the emergency department after wife found him unresponsive at home. Ventricular fibrillation cardiac arrest was diagnosed; while admitted at ICU, patient had two other instances of ventricular tachycardia leading to separate episodes of cardiac arrests. The patient was then discharged to acute rehabilitation facility due to anoxic/hypoxic brain injury.


Discussions:

Bethanechol is a direct acting parasympathomimetic agent that acts on postganglionic parasympathetic receptors. Bethanechol exerts its effects on bladder by increasing the tone of the detrusor muscle of the bladder to initiate micturition. The parasympathetic effect of M2 receptors in the heart stimulate the SA and AV node resulting in bradycardia, dysrhythmias and potentially cardiac arrest.

Prior to the cardiac arrest, patient was doing well after finishing the first course of rehabilitation after stroke. Physical therapy noted patient required set up for eating and grooming and minimal assist with transfers.  After the cardiac arrest and onset of the anoxic brain injury, however, patient severely declined in his functional status. Patient required total assist with tube feed for eating, total assist for grooming, and total assist with lift for transfers.

 


Conclusions:

Careful medication review should be done in patients with neurogenic bladder as a result of an ischemic stroke. As seen in our patient, non-selective medications like bethanechol, might lead to life threatening complications like dysrhythmias and cardiac arrest.  A complex history of a stroke and subsequent anoxic brain injury might be life altering for both the patient and caretakers.