Viagra is a phosphodiesterase-5 enzyme inhibitor used primarily in the treatment of erectile dysfunction in males. Erectile dysfunction is defined as the inability to get or maintain a meaningful erection. This condition causes significant psychological and physical distress for millions of males and their partners. It can also be used less commonly for the treatment of cardiovascular conditions such as pulmonary hypertension. When it is used for erectile dysfunction this medicine is taken on an as needed basis. However, if needed and in the absence of contraindications, it can be taken once daily. When used for the treatment of pulmonary arterial hypertension it is taken each day on a regular schedule. For its most common use, erectile dysfunction, it is typically taken one hour prior to sexual activity and the effects can last anywhere from thirty minutes to four hours. Doses can range from 25 to 100 milligrams.
Like any medication Viagra can cause side effects. Most common side effects including flushing of the skin, headache, and upset stomach. Some people experiences changes in their perception of colors and other eye changes like sensitivity to light. Less commonly Viagra can cause nosebleeds, dizziness, and difficulty sleeping. A relatively rare, but serious, adverse reaction associated with taking Viagra is called priapism. Priapism is an erection lasting more than four hours and can cause permanent damage to genital vessels if not treated promptly. Anyone taking Viagra should be warned to go to his nearest emergency facility if he experiences an erection lasting longer than four hours. Those with underlying conditions like sickle cell anemia, multiple myeloma, and certain types of leukemia are more susceptible to this unfortunate complication.
It is also critical for men taking Viagra to know that there is a severe interaction between this medicine and nitrate medications used to treat chest pain and other heart conditions. If these medications are taken together it can result in a life threatening drop in blood pressure known as hypotension. Those taking nitrates should wait 24 hours after their last does of mediation before taking Viagra. Fortunately, aside from this, there are very few drug to drug interactions associated with the use of Viagra. Those with severe kidney disease should not take Viagra or may need to take smaller doses than those without kidney problems. For this and many other reasons Viagra does require a prescription from a licensed medical provider and is not available for sale without a prescription or over the counter. It is important to talk to your doctor about potential problems associated with this medicine as well as weather or not sexual activity is safe for you prior to beginning Viagra therapy.
Viagra was the first drug of its kind and revolutionized the pharmaceutical market in many ways. Interestingly, it was developed initially for treatment of life threatening pulmonary arterial hypertension, but its effect in treating erectile dysfunction was discovered along the way. This “accidental discovery” has resulted in record breaking sales and profits for Pfizer, the drugs developer.