What is a common side effect of sildenafil (Viagra) that the client should be aware of?

Frequent headaches are a well-documented side effect of sildenafil, commonly known as Viagra. This medication is a phosphodiesterase type 5 (PDE5) inhibitor, and its action leads to increased blood flow by relaxing the blood vessels in the penis, which can also affect other areas of the vascular system. A common response to this change in vascular dynamics is the occurrence of headaches, which can result from vasodilation and changes in intracranial pressure.

While the other options may seem relevant in a broader context, they don't represent common or expected side effects associated with sildenafil. Increased libido is not a direct effect of the medication; rather, it may enhance sexual performance but does not directly influence sexual desire. Higher blood pressure is also contrary to what sildenafil is intended to achieve, as it is designed to lower blood pressure in the pulmonary arteries, and increased appetite is not recognized as a side effect of the drug. Understanding these common side effects is crucial for clients taking sildenafil to manage their expectations and ensure they are aware of what to monitor while on the medication.