While each PDE5 inhibitor differs slightly, they’re very similar in treating erectile dysfunction. This increase in blood flow results in a firmer, longer-lasting erection. You should also call your insurance company to see if they cover erectile dysfunction medications. In , Pfizer scientists discovered that sildenafil, which also inhibits the PDE5 enzyme, caused penile erection in males participating in a clinical study of a heart medicine. Cialis should not be used by patients taking nitrates such as nitroglycerin tablets or patches because the combination of these with Cialis could significantly lower blood pressure and lead to fainting or even death in some men. Taking more than 1 dose every 24 hours can cause heart issues and other problems. Patients who have a condition called “left ventricular outlet obstruction” from valvular problems or heart muscle enlargement may get side effects such as fainting or light-headedness.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. When to take Cialis for best results. Cialis treats ED in 80% of cases. If you have drunk more than units of alcohol, you may find Cialis is less effective. Food does not impact how Cialis works. We advise trying an ED treatment 8 times before giving up, considering a higher dose, or seeking an alternative. Tadalafil (Cialis) is a medicine used to treat erectile dysfunction (ED, also called impotence) and problems with urination caused by an enlarged prostate (benign prostatic hypertrophy or BPH). Tadalafil works by helping to relax the blood vessels in the penis, allowing blood to flow into the penis, and causing an erection.