What should a nurse do if a client with a history of hypertension is receiving morphine?

Monitoring blood pressure regularly is essential when a client with a history of hypertension is receiving morphine. Morphine can cause vasodilation and may lead to a decrease in blood pressure due to its opioid effects, potentially exacerbating the client’s existing condition of hypertension. By keeping track of the blood pressure, the nurse can identify any significant changes that may require intervention, ensuring the client's safety and effective pain management.

The other options may not directly address the immediate concerns related to morphine administration in a hypertensive client. While increasing fluid intake can be beneficial for hydration, it does not specifically relate to the effects of morphine. Limiting physical activity may be useful in some contexts but does not correlate directly with morphine’s impact on blood pressure. Checking oxygen levels, while important in many situations, is not the primary concern in relation to hypertension and morphine use. Hence, regular monitoring of blood pressure is the most appropriate action.