You take one 2. Ask your doctor if you are not sure whether any of your medications contain nitrates. You should also call your insurance company to see if they cover erectile dysfunction medications. There are many safe, reliable online services offering ED prescriptions. Stendra avanafil : This is an as-needed medication taken 30 minutes before sex and can last up to six hours. Talk with your healthcare provider about which might be best for you.Tadalafil’s effect on sexual ability may last up to 36 hours. The second way to treat ED is to take tadalafil regularly, once a day every day. If you take it this way, you may attempt sexual. It contains the active ingredient tadalafil. (An active ingredient is what makes a drug work.) Is the price for Cialis mg tablets more than for lower doses of the drug? The price of tadalafil may depend on the strength. Tadalafil comes in strengths of milligrams (mg), 5 mg, 10 mg, and 20 mg. As with other drugs, the cost of tadalafil .