A nurse is evaluating the response of a client who received twice the prescribed dose of digoxin. Which of the following actions should the nurse take first?

Digoxin is a cardiac glycoside that inhibits the sodium-potassium ATPase pump, increasing intracellular calcium and myocardial contractility. It possesses a narrow therapeutic index, making toxic accumulations common. Early toxicity manifests as anorexia, nausea, and blurred or yellow-tinted vision, while severe toxicity causes life-threatening dysrhythmias. Rationale: A. Notifying the provider is a necessary step in the management of a medication error, but it is not the initial action. The nurse must first possess objective clinical data regarding the client's current physiological status to provide a comprehensive report. Assessment always precedes notification in the nursing process to ensure the provider can make informed decisions. B. Obtaining the client's vital signs is the priority action because the nurse must assess for immediate life-threatening complications like severe bradycardia or hypotension. Since digoxin significantly affects cardiac conduction, an overdose can trigger various arrhythmias. Assessing the client's stability provides the essential data needed to determine the urgency of further medical interventions. C. Initiating a medication error incident report is an administrative requirement that ensures institutional quality improvement and safety tracking. However, documentation is never the first priority when a client's safety is potentially compromised by a pharmacological overdose. The nurse must focus on clinical assessment and stabilization before completing necessary internal paperwork regarding the error. D. Checking the client's digoxin level is an important diagnostic step to quantify the severity of the overdose, but it takes time to process. Laboratory results do not provide immediate information about the client's current hemodynamic tolerance of the excess dose. The nurse should prioritize the physical assessment of the client over waiting for laboratory confirmation of serum levels.