Oral medications

Sildenafil (Viagra) was the first oral medicine approved to treat erectile dysfunction. It works by increasing the flow of blood to the penis so that a man can get an erection when he is sexually stimulated. Though the directions advise men to take the drug one hour before sexual activity, research indicates that the drug can sometimes work when taken from 30 minutes to four hours before intercourse.

Choose another disease or condition... Allergic Rhinitis Allergies, Food Allergy & Asthma Center Alzheimer's Disease Anxiety Aortic Aneurysms Arrhythmia Arthritis, Osteo- (OA) Arthritis, Rheumatoid (RA) Asthma Atopic Dermatitis Attention Deficit Hyperactivity Disorder (ADHD) Back Pain Brain Tumor Bones, Joints & Muscles Center Breast Cancer Brain & Behavior Center Brain Tumor Cancer Center    Brain Tumor    Breast Cancer    Cancer Prevention    Clinical Trials    Colorectal Cancer    Endometrial Cancer    Living With and Beyond Cancer    Lung Cancer    Prostate Cancer    Skin Cancer Cardiomyopathy Cataracts Cholesterol Control Clinical Trials Chronic Obstructive Pulmonary Disease (COPD) Colorectal Cancer Congenital Heart Disease Congestive Heart Failure (CHF) Coronary Artery Disease (CAD) Crohn's Disease Depression Diabetes Center Diabetes, Type 1 Diabetes, Type 2 Digestive Disorders Center Eczema Endometrial Cancer Erectile Dysfunction (ED) Eye & Vision Center Fibromyalgia Food Allergies Gallstone Disease Gastroesophageal Reflux Disease (GERD) GERD Glaucoma Hay Fever Headache Heart Center Hepatitis A Hepatitis B Hepatitis C High Blood Pressure Hypertension Hypertrophic Cardiomyopathy (HCM) Impotence Insomnia Irritable Bowel Syndrome (IBS) Living With and Beyond Cancer Losing Weight Lung Cancer Macular Degeneration Memory Loss Osteoarthritis (OA) Osteoporosis Parkinson's Disease Peptic Ulcer Prediabetes Prostate Cancer Respiratory Disorders Center Restless Legs Syndrome (RLS) Rheumatoid Arthritis (RA) Sexual & Reproductive Health Center Sinusitis Skin Cancer Sleep Apnea Sleep Center Stroke Type 1 Diabetes Type 2 Diabetes Ulcerative Colitis (UC) Weight Control More about Sexual and Reproductive Health Get more online resources about ED Erectile Dysfunction-Related Clinical Trials Information Email this page Print this section

Take Viagra exactly as directed. Do not increase or decrease the dosage of Viagra or take the drug more often than prescribed by your doctor. Do not take Viagra more than once a day.

Men who are on nitrate medications such as nitroglycerine should not take Viagra, since the combination of Viagra and nitrates can cause blood pressure to dip too low (hypotension). The most common side effects of Viagra are dyspepsia (indigestion), nasal congestion, flushing, headaches, and transient visual disturbance.

Before taking Viagra, tell your doctor if you:

• Are allergic to Viagra or any other drugs
• Are taking any prescription or over-the-counter medications including herbal and dietary supplements
• Are scheduled for surgery
• Take nitroglycerin or a long-acting nitrate to treat chest pain. The combination of Viagra and these drugs can cause dangerously low blood pressure.
• Have ever had a heart attack, heart disease, angina (chest pain associated with heart disease), stroke, or retinitis pigmentosa (a rare disease of the eye that causes vision loss)

Other oral medications that work in a similar fashion are tadalafil (Cialis) and vardenafil (Levitra).