Your doctor or other health care professional can recommend one for you based on these factors, other health conditions you have and any other medicines you take. Oral ED medicines might not work or might be dangerous if you also take any of the following: Nitrate medicines. They enhance the effects of a chemical the body makes that relaxes muscles in the penis, called nitric oxide. You can take it in a small dose daily or in a larger dose as needed. Simply fill out a short questionnaire and wait for one of our doctors to reach out to you about your best options. Common ones include: Flushing of the skin.a light-headed feeling, like you might pass out. Common sildenafil side effects may include: flushing (warmth, redness, or tingly feeling); headache, dizziness; heartburn, nausea, or . 19th August Manual Health Centre In 30 seconds What’s the best Viagra for men? In truth, there’s only one Viagra. That’s Pfizer’s drug powered by the active ingredient . Viagra and Cialis are the most popular ED (erectile dysfunction) drugs in the world, but they’re not the only ones. They’re equally safe and effective, but they differ a bit in how .