This medicine is used in the treatment of high blood pressure in blood vessels between the heart and the lungs. This rare condition is more likely to occur if you have heart disease, high blood pressure, High Cholesterol, Diabetes, or eye problems, are more than 50 years old, or if you smoke. Viagra may lead to decrease or loss in eyesight with one or both eyes. If you have serious liver problems, your doctor may start you at the lowest dose of Viagra which is 25 mg. Seniors: If you are 65 years of age or older, you may need a lower dose of Viagra Sildenafil. If you place your order online, please select “I would like my prescription transferred from another pharmacy” or “I would like you to contact my doctor to obtain my prescription” during the order process.The medication Viagra is manufactured by Pfizer Canada Inc and it comes in 25 mg, 50 mg and mg dosage forms in a blister pack of 4 tablets. health care professional about .  · There’s a Free, Low-Risk Alternative to Viagra, Study Shows: ScienceAlert There’s a Free, Low-Risk Alternative to Viagra, Study Shows Health 03 November . Checking the legitimacy of your online pharmacy. Two ways you can check if your online pharmacy is legitimate: For sites listing a Canadian street address, check with the .