A client on bethanechol may develop a cholinergic crisis. Which medication should be readily available to treat this condition?

• A. Atropine sulfate (Isopto Atropine)
• B. Diphenhydramine hydrochloride (Benadryl)
• C. Epinephrine hydrochloride (Adrenalin chloride)
• D. Acetaminophen (Tylenol)

Answer: (A)

Bethanechol is a direct muscarinic agonist, so an overdose or cholinergic crisis produces excessive muscarinic effects such as increased secretions, bronchoconstriction, bradycardia, miosis, diarrhea, and urination. The treatment is to block those muscarinic receptors, which is achieved with atropine. Atropine sulfate is a competitive muscarinic antagonist that counteracts the unwanted cholinergic effects, helping to dry secretions, relax bronchial smooth muscle, and speed up the heart as needed. Because the crisis centers on muscarinic overstimulation, atropine directly addresses the root problem.

Diphenhydramine won’t counteract muscarinic overstimulation. Epinephrine is for severe allergic reactions or cardiac/airway emergencies but doesn’t specifically reverse muscarinic effects from bethanechol. Acetaminophen has no role in reversing cholinergic excess.