Final answer:
A medication list that includes nitrates option (c) is a contraindication for the use of sildenafil (Viagra). Sildenafil is a PDE5 inhibitor that treats ED but can cause severe hypotension if combined with nitrates, posing significant risks to patients with heart conditions.
Step-by-step explanation:
The nurse is performing an assessment of a patient asking for a prescription for sildenafil (Viagra). The contraindication to its use would be a medication list that includes nitrates option (c). Sildenafil, a PDE5 inhibitor, is used to treat erectile dysfunction (ED). It works by promoting vasodilation in the vasculature of the body, which improves blood flow and can help achieve an erection. However, its use is contraindicated for patients taking nitrates for heart conditions, as it can lead to severe and dangerous drops in blood pressure. Patients with heart conditions, especially those taking nitrates, are advised to avoid Viagra or consult their physician due to the risks involved, including reported deaths.