These PDE5 inhibitors may cause headache, flushing, drop in blood pressure, or other adverse effects. That’s not to say there aren’t just as many illegitimate sites. It’s available in 25 mg, 50 mg, and mg tablets and lasts up to 18 hours. Stendra avanafil : This is an as-needed medication taken 30 minutes before sex and can last up to six hours. It’s available in 50 mg, mg, and mg tablets.Use a mail-order pharmacy to get your medication. Using a mail-order pharmacy might help lower your cost for Cialis. Plus, you could get your medication without leaving home. strength safety effectiveness stability quality Usually, generic drugs aren’t available until the expiration of the brand name’s patent. Eli Lilly and Company’s patent for Cialis expired in Yes, a person must have a prescription for tadalafil. If they do not wish to visit their regular doctor, individuals can obtain a prescription online following a virtual consultation from an.