Accordingly, caution is necessary for patients already on ritonavir when prescribing sildenafil. Talk to your doctor about eating grapefruit and drinking grapefruit juice while taking this medicine. However, if you take sildenafil with a high-fat meal, it will take longer for the medication to start to work. Epistaxis was reported higher in sildenafil-treated patients with a concomitant oral vitamin K antagonist. The trial results revealed that sildenafil had improved the patients’ depression, anxiety, and self-esteem. Brand names Why is this medication prescribed? You can take sildenafil with or without food. · Drug information provided by: Merative, Micromedex ® US Brand Name Revatio Viagra Descriptions Sildenafil is used to treat men who have erectile dysfunction . Viagra is a brand-name medication that contains the active drug sildenafil. This active drug comes as a generic medication, too. Sildenafil and brand-name Viagra . Sildenafil (Viagra) is used to treat erectile dysfunction (impotence; inability to get or keep an erection) in men. Sildenafil (Liqrev, Revatio) is used to improve the ability to exercise in Missing: scientific name.