VIVUS Inc., a California-based biopharmaceutical company, has received the US Food and Drug Administration (FDA) approval for its Stendra (avanafil), a new drug to treat erectile dysfunction.

Erectile dysfunction is when a man has trouble getting or keeping an erection. An estimated 30 million men in the United States are affected by erectile dysfunction.

Stendra is a pill that patients take on an as-needed basis 30 minutes before sexual activity. Doctors should prescribe the lowest dose of Stendra that provides benefit.

“This approval expands the available treatment options to men experiencing erectile dysfunction, and enables patients, in consultation with their doctor, to choose the most appropriate treatment for their needs,” said Victoria Kusiak, M.D., deputy director of the Office of Drug Evaluation III in the FDA’s Centre for Drug Evaluation and Research.

Stendra belongs to a class of drugs called phosphodiesterase type 5 (PDE5) inhibitors, which are used to help increase blood flow to the penis. As with other PDE5 inhibitors, Stendra should not be used by men who also take nitrates, commonly used to treat chest pain (angina), because the combination can cause a sudden drop in blood pressure.

PDE5 inhibitors may rarely cause color vision changes. In rare instances, men taking PDE5 inhibitors have reported a sudden loss of vision in one or both eyes. Sudden loss or decrease in hearing has also been reported in patients taking PDE5 inhibitors. Patients who experience a sudden loss of vision or hearing should stop taking PDE5 inhibitors, including Stendra, and call a doctor right away.

The most common side effects reported in greater than 2 per cent of patients in the clinical studies of Stendra include headache, redness of the face and other areas (flushing), nasal congestion, common cold-like symptoms (nasopharyngitis), and back pain. In rare cases, patients taking Stendra and other PDE5 inhibitors may get an erection lasting four hours or longer that will not go away (priapism). If this happens, patients should seek immediate medical care.

Stendra’s safety and efficacy were established in three double-blind, placebo-controlled clinical studies. A total of 1,267 patients were randomly assigned to take Stendra for up to 12 weeks at doses of 50 milligrams (mg), 100 mg or 200 mg, or a placebo as needed about 30 minutes before sexual activity.

At the start of the studies and every four weeks thereafter, patients completed questionnaires to evaluate erectile function, vaginal penetration and successful intercourse. Results showed patients taking Stendra experienced statistically significant improvement in all three endpoints for all three doses of Stendra studied.

To further evaluate Stendra’s safety, a subset of patients from two of the studies were enrolled in another trial to receive up to an additional 40 weeks of treatment. Patients were initially given Stendra at the 100 mg dose, but could have their dose increased to 200 mg or decreased to 50 mg based on their individual response to treatment. Results showed that the side effects commonly reported in patients using Stendra did not worsen over time.

The FDA, an agency within the US Department of Health and Human Services, protects the public health by assuring the safety, effectiveness, and security of human and veterinary drugs, vaccines and other biological products for human use, and medical devices. The agency also is responsible for the safety and security of our nation’s food supply, cosmetics, dietary supplements, products that give off electronic radiation, and for regulating tobacco products.