Some people buy sildenafil online without a prescription. This medicine comes with a patient information leaflet. These patients had erectile dysfunction at baseline that was characterized by median categorical scores of 2 a few times on principal IIEF questions. In these studies, involving about patients, analyses of patient diaries showed no effect of VIAGRA on rates of attempted intercourse about 2 per week , but there was clear treatment-related improvement in sexual function: per patient weekly success rates averaged 1. Do not use this medicine if you are also using a nitrate medicine, often used to treat angina or high blood pressure. 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.Viagra (sildenafil) is a prescription drug that’s used to treat erectile dysfunction (ED). The drug comes as a tablet you’ll take by swallowing. It’s usually taken as needed about 1 hour. 11 years ago. Save. I’ve just read this on another forum about Viagra and Thailand; It is a controlled substance and legally cannot be purchased without a Prescription. It is illegal to have it in your posession without a prescription as well. Not sure if it’s true but sounds . 11 years ago. Save. I’ve just read this on another forum about Viagra and Thailand; It is a controlled substance and legally cannot be purchased without a Prescription. It is illegal to have it in your posession without a prescription as well. Not sure if .