This article is written to clarify the medical facts behind the kamagra vs viagra discussion, using evidence, regulatory standards, and real clinical experience instead of marketing claims. Viagra and Cialis are oral medications for treating erectile dysfunction. Check out side-by-side comparisons of these ED pills. Which is better viagra or cialis? Cialis and Viagra are both PDE5 inhibitors used for the treatment of erectile dysfunction (ED). Both only work when a man is sexually aroused. Cialis lasts for around 36 hours compared with only 4 to 5 hours for Viagra. Tadalafil (Cialis) is as effective as sildenafil (Viagra), and vardenafil (Levitra) with similar side effects except for back pain that occurs occasionally with tadalafil, probably because of the long half-life. You may already know most of the names: Cialis, Levitra, Staxyn, Stendra, Viagra. Learn more about these medications that can help men with erectile dysfunction get and keep an erection. Learn how Levitra and Viagra compare in treating ED. Understand their differences, similarities, and what to consider for effective results. Taking an ED drug produces an erection sufficient to start intercourse in about 70% of otherwise healthy men. Does it make any difference which of the four drugs for erectile dysfunction you take? Yes, there can be differences, says Dr. Louis Liou, chief of urology at Harvard-affiliated Cambridge Health Alliance in Boston. Which is the best medication for ED? Viagra, Cialis, or Stendra? Learn about each pill and compare the effects, duration, and side effects of ED drugs here. Viagra (sildenafil) and Cialis (tadalafil) are leading phosphodiesterase-5 (PDE5) inhibitors prescribed for erectile dysfunction (ED). Both enhance blood flow to the penis during sexual. Cialis (tadalafil) and Viagra (sildenafil) treat impotence (erectile dysfunction, ED) and enlarged prostate (BPH). Cialis lasts longer in the body than Viagra (about 18 hours compared to 4-6) so it can allow one to sustain an erection longer.