Final answer:
The most important intervention is to review the client's use of OTC medications.
Step-by-step explanation:
The most important intervention for the nurse to implement when assessing the adult male with hypertension and 2+ pitting edema in both ankles is to review the client's use of over the counter (OTC) medications. This is important because certain medications, such as nonsteroidal anti-inflammatory drugs (NSAIDs), can cause fluid retention and worsen edema. By reviewing the client's OTC medication use, the nurse can identify any medications that may be contributing to the edema and recommend appropriate adjustments or alternatives.