Oral ED medicines might not work or might be dangerous if you also take any of the following: Nitrate medicines. Severe liver disease. The information provided is for educational purposes only and is not intended to replace discussions with a healthcare provider. This medication is taken with or without food an hour before sex. Its effects often last for 4 to 5 hours. These small differences affect the way each medication works, such as how quickly it takes effect and wears off, and the possible side effects. Stop taking VIAGRA and call your healthcare provider right away if you have any sudden vision loss sudden hearing decrease or hearing loss.MNT ‘s review. Lemonaid sells Cialis in these forms: Cialis: available in doses of 5, 10, and 20 mg, starting at $65 per tablet. Daily Cialis: 5 mg tablet with pricing starting from $50 per tablet. How much does generic Viagra cost? Generic Viagra usually costs anywhere from about $2–$18 for each tablet depending on the dosage and manufacturer. Can I buy generic . The four main medicines taken by mouth for erectile dysfunction are: Avanafil (Stendra). Sildenafil (Viagra). Tadalafil (Cialis). Vardenafil. These medicines are called PDE5 inhibitors. They enhance the effects of a chemical the body makes that relaxes muscles in the penis, called nitric oxide.