Flibanserin is not approved in Australia. Use protective measures and ask your doctor if you have any questions about this. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive. Sildenafil may not be safe to take for people with certain medical conditions including: a past history of stroke or heart attack in the last 6 months retinitis pigmentosa an eye disease It can also interact with many other medicines, particularly nitrates used in heart disease , amyl nitrite and blood pressure medicines. This medicine comes with a patient information leaflet. You could also ask your pharmacist for advice on other ways to help you remember to take your medicine. Remove the cap by pushing it down and twisting it counter-clockwise.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 adults (Liqrev, Revatio) and children 1 year of age and older (Revatio) with pulmonary arterial hypertension (PAH; high blood pressure in the vessels carrying blood to the . What Happened When I Took Viagra Recreationally. 1. Viagra was effective for much longer than four hours. Shutterstock. Viagra comes in three different sizes: 25mg, 50mg, or mg. In the past, I’ve found that 25mg always did the job just fine. However, my journey begins with a bottle of the mg tabs which I’ve chosen to cut into thirds. Viagra is used to treat erectile dysfunction (ED). It decreases ED symptoms by helping you get and keep an erection. Erections happen when a protein called cyclic guanosine .