When will Cialis be available to pharmacies? The four main medicines taken by mouth for erectile dysfunction are: Avanafil Stendra. Ask your doctor if you are not sure whether any of your medications contain nitrates. Because they are the same class of medications, they have similar side effects and effectiveness. This increased blood flow can cause an erection. A phone or video consultation is sometimes required for legal purposes. Here are some key factors to consider when deciding: Pricing: Know how much your monthly supply will cost with shipping and tax.Generic Cialis Availability. Last updated on Cialis is a brand name of tadalafil, approved by the FDA in the following formulation(s): CIALIS (tadalafil – tablet;oral) Manufacturer: LILLY Approval date: November 21, Strength(s): 5MG, 10MG, 20MG ; Manufacturer: LILLY Approval date: January 7, Cialis is available as the generic drug tadalafil. A generic drug is an exact copy of the active drug in a brand-name medication and is considered just as safe and effective. How Cialis Works. Tadalafil and other PDE5 inhibitors primarily work by inducing muscle relaxation. Tadalafil stops the breakdown of a chemical responsible for relaxing muscles. In ED and PAH, the drug targets muscle cells in blood vessels. When the blood vessel muscle cells relax, this expands the vessel and increases blood flow; this .