Read and follow these instructions carefully before you start using sildenafil and each time you get a refill of your medicine. The pharmacokinetics of sildenafil in patients with severely impaired hepatic function Child-Pugh Class C have not been studied [see Dosage and Administration 2. Dosage and strength for pulmonary hypertension Sildenafil tablets for pulmonary hypertension come in 10mg and 20mg strengths. When hypertension occurs in the lungs, the heart must work harder to pump enough blood through the lungs. Do not use more of it and do not use it more often than your doctor ordered. Also tell your doctor if you or any of your family members have or have ever had an eye disease such as retinitis pigmentosa an inherited eye condition that causes loss of vision or if you have ever had sudden severe vision loss, especially if you were told that the vision loss was caused by a blockage of blood flow to the nerves that help you see.The dose can be increased to mg or decreased to 25mg depending on its effect. Take sildenafil up to 4 hours before you want to have sex. For sildenafil to work properly, you’ll need to be sexually excited. Dosage and strength for pulmonary hypertension. Sildenafil tablets for pulmonary hypertension come in 10mg and 20mg strengths.  · Drugs and Supplements Sildenafil (Oral Route) Description and Brand Names Before Using Proper Use Precautions Side Effects Products and services Proper . Works in minutes and lasts for up to 5 hours. Starting from $ Prices starting at $ Form Tablet. Available doses 25mg, 50mg, mg. Sildenafil. See treatments. Sildenafil: Same as Viagra, but a little cheaper. Cancel anytime subscriptions.