What complication should be monitored for in a patient starting finasteride?

When a patient begins treatment with finasteride, the most relevant complication to monitor for is angioedema. Finasteride is primarily used for benign prostatic hyperplasia and male pattern baldness, and while it can lead to side effects, angioedema, a condition characterized by rapid swelling of the deeper layers of the skin, can occur as an allergic reaction to the medication. Monitoring for signs of angioedema, such as swelling in the face, lips, throat, or difficulty breathing, is crucial, as these symptoms could indicate a serious allergic response that may require immediate medical attention.

The other options, such as prostate enlargement, weight gain, and blood pressure fluctuations, are not direct complications associated with finasteride. In fact, finasteride is intended to address prostate enlargement by reducing dihydrotestosterone levels, which contributes to this condition. While some individuals may experience weight gain over time or variations in blood pressure due to other underlying health issues or medications, these are not specifically linked to the initiation of finasteride therapy. Therefore, the focus should be on monitoring for angioedema as a significant and potentially dangerous side effect.