Tadasiva Tadalafil is an FDA-approved generic form of Cialis, used to treat erectile dysfunction (ED) in men. It relaxes the blood vessels and increases blood flow to the penis during sexual stimulation. The drug works by blocking the breakdown of cGMP, a naturally produced substance that regulates flow of blood to the penis and is necessary for an erection. Tadasiva is less expensive than branded Cialis, and is just as effective for treating ED. Tadasiva Tadalafil is a medication used to treat erectile dysfunction. It is a type of phosphodiesterase 5 inhibitor (PDE-5) which works by relaxing the muscles of the penis and helping it to fill with more blood, leading to improved and prolonged erections. Common side effects include headaches, back pain and a stuffy or runny nose. It should be taken approximately one hour before planned sexual activity. Talk to your doctor before starting Tadasiva Tadalafil.