What guidance should a nurse give to a client about administering edrophonium for a myasthenic crisis?

The choice indicating that edrophonium takes effect in less than 1 minute is correct because edrophonium is a fast-acting acetylcholinesterase inhibitor used primarily for the diagnosis and treatment of myasthenic crisis. Upon administration, its effects can be observed almost immediately, typically within 30 to 60 seconds. This rapid onset allows for prompt assessment of the patient's condition and assists in determining the effectiveness of the treatment during a myasthenic crisis.

In contrast, other options present misconceptions or inaccuracies about edrophonium. For example, while it may be necessary to consult a doctor if no effects are noted, the immediate action and monitoring after administration are crucial, making the quick onset of action more pertinent. Additionally, edrophonium does not lead to permanent resolution of weakness; it provides temporary symptomatic relief, and therefore is not a curative treatment for underlying myasthenia gravis. Lastly, edrophonium is a prescription medication, not an over-the-counter drug, emphasizing the importance of professional medical guidance in its use.