Filitra 20 mg works by blocking the enzyme phosphodiesterase type 5 (PDE5). This increases levels of cGMP, a chemical that relaxes smooth muscles in blood vessels. As a result, blood flow to the penile tissue improves during sexual arousal. It does not increase sexual desire and will not produce an erection without stimulation. Filitra 20 mg should not be taken with nitrate medications (used for chest pain), as this can cause a dangerous drop in blood pressure. Caution is also needed in men with heart disease, liver or kidney problems, or those taking multiple blood pressure medications. https://www.genericday.com/filitra-20-mg.html