Viagra is the brand name for the drug sildenafil. The drug is primarily used in the treatment of erectile dysfunction, or impotence. Viagra works by increasing blood flow to the penis upon sexual stimulation. The increased blood flow typically results in a sustained erection, according to MedlinePlus, a National Institutes of Health website. Though not a complete cure, the drug does allow patients to participate in sexual intercourse. Viagra is a potent medication and should not be used in situations where it is contraindicated.
Nitrate Drug Usage
Patients who have been prescribed a drug that contains nitrate should not use Viagra, states Drugs.com. Nitrates are drugs that are commonly prescribed to patients who are experiencing chest pain. Examples include isosorbide dinitrate and nitroglycerin. The medication relieves the pain by lowering blood pressure in the arteries and other blood vessels. Viagra will often enhance this effect. Patients taking both drugs experience a severe drop in blood pressure, which can lead to organ damage, heart attack, stroke and loss of consciousness. Therefore, any patient who is already taking a nitrate drug should never use Viagra to treat erectile dysfunction.
Heart Problems
Heart disease and other heart problems can be a contraindication for Viagra, according to FamilyDoctor.org. Patients suffering from coronary artery disease, heart failure, congenital heart defects or other structural abnormalities in the heart should not be given Viagra. The drug can have serious, life-threatening side effects in patients with heart disease. Any patient with heart problems should consult with a doctor prior to using Viagra. In mild cases, the drug may be used, but in severe heart disease that Viagra is contraindicated.
Certain Street Drugs
There are certain illegal street drugs that should never be used at the same time as Viagra, reports MedlinePlus. Any drugs that may contain amyl nitrate or butyl nitrate should be avoided. These drugs, commonly called "poppers," contain nitrate, which can cause a sharp drop in blood pressure. Patients who have ingested both drugs will often experience chest pain and loss of consciousness. They may die if proper treatment is not provided.
Allergy
Any patient who has exhibited a previous allergic response to Viagra should not be given the drug again, states Drugs.com. Patients who have developed an allergy to the drug may have complained of hives, difficulty breathing or a rash when they first took the drug. If they take Viagra again, the symptoms may worsen and can even be life-threatening. These patients must avoid Viagra and will have to use another drug to treat erectile dysfunction.
