Final answer:
The highest priority action before administering preoperative diazepam is identifying the client's med allergies.
Step-by-step explanation:
The highest priority action that the nurse should take prior to administering preoperative diazepam (Valium) is C. Identifying the client's med allergies. It is crucial to identify any allergies that the client may have to prevent an allergic reaction from the medication. This information is essential for the client's safety. Once the allergies have been identified, the nurse can then administer the medication as prescribed and proceed with other actions.
Teaching the client about the purpose of the medication (A. Teaching the client about the purpose of the med) can be done after verifying allergies and administering the medication. Administering the medication (B. Administering the med to the client at the prescribed time) can be done once the allergies have been identified. Documenting the client's anxiety level (D. Documenting the client's anxiety level) is important but is not the highest priority compared to ensuring the client's safety by identifying allergies.