Avanafil works to treat penile erectile dysfunction and should be used as prescribed. Avanafil can enhance the nitric oxide (NO)-cGMP pathway by selectively inhibiting PDE5 during sexual stimulation, elevating the cGMP level and leading to relaxation of penile cavernous smooth muscle, so that patients with erectile dysfunction can produce a natural erectile response to sexual stimulation. Therefore, it can be used in the treatment of penile erectile dysfunction. Adverse reactions to Avanafil can be seen as headache, flushing, nasopharyngitis, nasal congestion, low back pain, muscle pain, upper respiratory tract infections, influenza, bronchitis, sinusitis, dyspnea, hypertension, nausea, constipation, and skin rash. This product is contraindicated in people who are allergic to this product, people who are taking nitrates, women, people under 18 years old. The combination of this product with nitrates can lead to low blood pressure, dizziness, heart attack, fainting, stroke. It should be used appropriately under medical supervision.