Sildenafil Interactions

Sildenafil is metabolized primarily by CYP3A4. Grapefruit juice inhibits intestinal CYP3A4 and modestly increases sildenafil AUC by about 23 percent while delaying peak concentration, which can worsen the headache, flushing, dizziness, and hypotension typical of PDE5 inhibitors.

Beetroot is high in dietary inorganic nitrate that the body converts to nitric oxide, the same vasodilator pathway amplified by PDE5 inhibitors like sildenafil. While organic nitrate drugs (not dietary) are the formal contraindication, large doses of beetroot juice can meaningfully lower blood pressure and may add to sildenafil's vasodilatory effect.