Tell your doctor if sildenafil is not working well or if you are experiencing side effects. Sildenafil is also sometimes used to treat pulmonary hypertension high blood pressure in the blood vessels that supply the lungs. If you experience chest pain, dizziness, or nausea during sex, seek immediate medical help. Take sildenafil as needed before sexual activity. If you have erection problems sildenafil works by temporarily increasing blood flow to your penis when you get sexually excited. If you buy sildenafil for erectile dysfunction, it can also be known by the brand names Viagra, Aronix, Liberize and Nipatra. It depends on the platform and insurance provider.Cialis lasts up to 36 hours in the body, while Viagra lasts 4–6 hours in the body. Both are taken 30 minutes before sex. Cialis can cause limb pain, while Viagra can cause vision change, rash. Examples of Viagra’s more commonly reported side effects include: headache. flushing (temporary warmth, redness, or deepening of skin color) stuffy nose. indigestion (upset stomach) mild vision. Medications Prescribed: Viagra, Cialis, Cialis Daily, Levitra, tadalafil, sildenafil, vardenafil. Generic offered: Yes. Why We Chose It. The simple combination of Rex MD’s online platform, its helpful customer service, and the abundance of ED treatment options make it a one-stop shop for all your sexual health needs.