The patent on Revatio indicated for pulmonary arterial hypertension rather than erectile dysfunction expired in late If this is achieved then a license can be considered. You can take this medicine with or without food 30 minutes before sex, depending on the dose. This means that if you are using the brand-name medication and decide to switch to the generic, then you are unlikely to notice any new side effects. Retrieved 6 October Drug Images What is Viagra? If you have erectile dysfunction (ED), your doctor may recommend that you take Viagra. It’s a prescription drug that’s used in adult . Sildenafil (Viagra). This medicine works best when you take it on an empty stomach an hour before sex. The body takes longer to absorb it after a high-fat meal or . The strongest Viagra pill is Viagra mg and can be prescribed when the 50mg dosage hasn’t provided the best results but also hasn’t caused any side effects. .