Which medication is contraindicated with nitrates due to risk of severe hypotension?

Which medication is contraindicated with nitrates due to risk of severe hypotension?

• A. Acetaminophen
• B. Sildenafil (Viagra)
• C. Lisinopril
• D. Amiodarone

Answer: (B)

Nitrates lower blood pressure by releasing nitric oxide, which boosts cGMP and causes smooth muscle relaxation and vasodilation. Sildenafil is a PDE5 inhibitor that prevents the breakdown of cGMP. When these two are used together, cGMP accumulates excessively, leading to a dangerous drop in blood pressure (severe hypotension) with potential dizziness, syncope, or worse. This is why a nitrate and sildenafil combination is contraindicated. The other medications listed don’t share this mechanism of amplifying the NO–cGMP pathway, so they don’t carry the same risk of severe hypotension with nitrates. In practice, nitrates should be avoided for a certain period after sildenafil use (and vice versa) to prevent this dangerous interaction.

Nitrates lower blood pressure by releasing nitric oxide, which boosts cGMP and causes smooth muscle relaxation and vasodilation. Sildenafil is a PDE5 inhibitor that prevents the breakdown of cGMP. When these two are used together, cGMP accumulates excessively, leading to a dangerous drop in blood pressure (severe hypotension) with potential dizziness, syncope, or worse. This is why a nitrate and sildenafil combination is contraindicated. The other medications listed don’t share this mechanism of amplifying the NO–cGMP pathway, so they don’t carry the same risk of severe hypotension with nitrates. In practice, nitrates should be avoided for a certain period after sildenafil use (and vice versa) to prevent this dangerous interaction.