For erectile dysfunction, it’s best to take sildenafil on an empty stomach. Bleeding disorders, history of or Stomach ulcer, or history of or—Chance of problems occurring may be increased. Different brands may not work the same way. Certain medications that are used for the heart, blood pressure, infections, or HIV may change the way that Viagra works for you or interact and increase your risk of adverse side effects. Some illegal “street” drugs called “poppers” such as amyl nitrate, butyl nitrate, or nitrite. Using this medicine with any of the following may cause an increased risk of certain side effects but may be unavoidable in some cases. How to take tablets Swallow tablets whole with a drink of water or juice but not grapefruit juice.VIAGRA usually starts to work within minutes. You may take it up to 4 hours before sexual activity. So there’s no need to rush. Eat smart before you start. VIAGRA can be . Missed dose Overdose Takeaway Drug Images Viagra treats erectile dysfunction (ED) in adults. It’s usually taken about 1 hour before sexual activity. Below, you’ll find information . Taking Viagra to Improve Sexual Function. 1. Ingest Viagra pills orally as directed by your doctor or pharmacist. The usual recommended dose is 50 mg, but in some cases, your .