Male impotence is a relatively common problem. Millions of men are embarrassed to admit they have such a problem and even more reluctant to seek treatment. Many diseases predispose men to impotence. These include diabetes, surgery or radiation for prostate cancer, spinal cord injuries or atherosclerosis. In the past, some treatments involved injections into the penis, implantable surgical devices, vacuum devices or penile suppositories. A new treatment now allows men with erectile dysfunction to take a pill to enhance response to sexual stimulation. In many cases, this will lead to an erection.
On March 27, 1998, the FDA approved Viagra (sildenafil citrate) as the first oral form of treatment (pill) for the treatment of erectile dysfunction. Viagra is manufactured by Pfizer, which received approval for the drug less than 6 months after submission to the FDA. Unlike other treatments for impotence that directly cause erections, Viagra affects chemicals released with sexual stimulation that cause blood flow to the penis by relaxation of smooth muscles. The pill is taken one hour before anticipated intercourse.
The initial evaluations of the drug involved 21 trials of over 4,000 men. Viagra showed a dose related response of improved sexual function in 70% of men with erectile dysfunction of all types. About 2.5% of men taking the medication discontinued it because of side effects. The most common side effects were headache, flushing and indigestion. Others reported visual blurring, color vision changes or increased sensitivity to light. Approximately 3% may have disturbances in the ability to perceive yellow and green lights for several hours after using the medication.
Because of its interaction with nitrates (including the heart medication nitroglycerin), men using these medications should not take Viagra. Several deaths have been reported in individuals using Viagra and certain heart medications, although a direct cause and effect relationship has not been established. The medication may also lower blood pressure. It may interact and cause increased side effects for those taking some anti-fungal agents, as well as specific antibiotics and anti-ulcer medications. People with sickle cell anemia, multiple myeloma or leukemia should be very careful in using Viagra as it may cause a painful erection that will not relax.
More clinical information about Viagra may be found in The New England Journal of Medicine, May 14, 1998, volume 338, pages 1397-1404. See an excellent article by LTC (Dr.) Peter Kovats on describing three erectile dysfunction medications.
Physicians at the FAA Civil Aeromedical Institute Aeromedical Certification Division recommend that the medication be used strictly in the dosages recommended by the manufacturer and all contraindications (reasons not to use the medication) be strictly observed. Pilots and air traffic controllers should not use Viagra within 6 hours of performing their (aviation) duties.
Levitra, approved by the FDA in August 2003, has a similar profile to Viagra. The FAA initially allowed the use of Levitra in pilots/controllers. However, in December 2003, the Federal Air Surgeon restricted pilots' authorization to use Levitra because of concerns about cardiac arrhythmias associated with its use. The Federal Air Surgeon re-instituted the authorization to take Levitra in September 2004 and initially required at least a six hour wait before participating in aviation related duties. During the Summer of 2012 the FAA extended the observation time for Levitra to 36 hours.
Cialis (tadalafil) is a longer acting erectile dysfunction medication (30 hours) recently approved in the United States for use. Cialis requires at least 36 hours before participation in safety sensitive duties because of the long half life.