The nurse is assisting a neurologist conducting a Tensilon test with Edrophonium. Which antidote will the nurse ensure is available in case of an emergency?

The Tensilon test uses Edrophonium to diagnose myasthenia gravis by temporarily increasing acetylcholine availability at the neuromuscular junction. This can rapidly improve muscle strength in affected patients. However, excessive cholinergic stimulation can occur as a complication, leading to bradycardia, bronchospasm, increased secretions, and hypotension. Because of these risks, an antidote must be immediately available during administration to reverse severe muscarinic effects. A. Glucagon is used primarily as an antidote for beta-blocker overdose or severe hypoglycemia, not for cholinergic toxicity. It does not counteract the muscarinic effects caused by Edrophonium. Therefore, it is not appropriate for managing adverse reactions during a Tensilon test. B. Epinephrine is used in anaphylaxis, cardiac arrest, and severe bronchospasm, but it does not specifically reverse the muscarinic effects of excessive acetylcholine. While it may support cardiovascular function in emergencies, it is not the primary antidote for cholinergic toxicity from edrophonium administration. C. Naloxone is an opioid antagonist used to reverse opioid overdose effects such as respiratory depression. It has no effect on cholinergic excess caused by Edrophonium and is not useful in managing complications of the Tensilon test. D. Atropine is the correct antidote because it is an anticholinergic agent that blocks muscarinic receptors and counteracts excessive acetylcholine activity. It is used to treat bradycardia, bronchospasm, and increased secretions that may occur during administration of Edrophonium. Having atropine available ensures rapid reversal of potentially life-threatening cholinergic effects.