Which patient should avoid using sildenafil (Viagra)?

Sildenafil (Viagra) is primarily used for the treatment of erectile dysfunction by increasing blood flow to the penis. However, one significant contraindication for its use is in patients who are taking nitrates for heart conditions. This is because both sildenafil and nitrates have the potential to lower blood pressure. When taken together, they can lead to a dangerous drop in blood pressure, which can result in serious cardiovascular complications.

The risk associated with this interaction is well-documented, which is why healthcare professionals advise men taking nitrates to avoid sildenafil. Patients on nitrates might include those with angina or other heart-related issues, where maintaining stable blood pressure is crucial for their safety.

In contrast, other options do not carry the same level of risk. For instance, a healthy male without erectile dysfunction may not need sildenafil, but it's not a safety concern. Similarly, a male with high blood pressure might be managed appropriately with medication and potentially monitored by their healthcare provider, and being under 18 does not inherently pose a risk relating to sildenafil itself, but it is generally not prescribed to this age group. However, the critical safety issue remains with those taking nitrates, making this a vital consideration in prescribing sildenafil.