Upon discovering a medication error, what should a nurse do first?

In the event of a medication error, the priority is to ensure the safety and well-being of the patient. The most appropriate initial action is to assess the client and notify the health care provider. This is because assessing the patient allows the nurse to gather crucial information regarding the patient's current condition, monitor for any adverse effects resulting from the medication error, and determine the immediate steps needed to mitigate harm.

Notifying the health care provider is essential to ensure that any necessary medical interventions can be taken promptly. This communication helps in determining the best course of action, such as whether additional treatments are required or if further monitoring is necessary.

While some other options may involve important steps, they do not prioritize immediate patient assessment and intervention. For instance, administering the correct medication before assessing the patient could lead to further complications. Completing an incident report and alerting colleagues are significant actions as well, but they typically follow the immediate assessment and stabilization of the patient to ensure their health is not compromised. Discontinuing the incorrect medication is also vital, but it is part of a broader set of actions that should follow an initial assessment. Thus, assessing the client and notifying the health care provider is the correct approach in this scenario.