The drug is approved for use in adults. Cialis was also investigated in combination with finasteride, another BPH medication, in another trial. Your doctor will probably tell you not to take tadalafil if you are taking street drugs containing nitrates. 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. Cialis is a brand-name prescription medication. It belongs to the drug class known as PDE5 inhibitors. Cialis is also highly effective in reducing the symptoms of BPH.FAQs Brand-name vs. generic Reducing long-term drug costs Financial assistance Next steps Overview of Cialis Cialis (tadalafil) is a brand-name prescription medication. The Food and Drug. The cost of the drug is different in different countries. You can buy this drug from us at a reduced price. Email. Password. Register to Trickster! One of the leaders in this area is the generic Cialis. $ 2. $ The Patriot. By Spiegel. Used chemicals, drugs, entering the body, cause an increase in the production of nitric oxide. The usual starting dose for once-daily Cialis is mg. Your doctor might increase the dose to 5 mg based on how you react to the medication. Take one tablet as prescribed at the same time each day.