News

24 Oct, 2006

Viagra Helps COPD Patients Control Pulmonary Blood Pressure

The drug sildenafil, popularly known as Viagra, may help people with chronic obstructive pulmonary disease control the illness-related blood pressure spikes in the heart's pulmonary artery, a new study found.

The medication, in addition to its use as a popular treatment for impotence, has already been approved by the U.S. Food and Drug Administration for the treatment of the chronic version of such blood pressure spikes, known as pulmonary arterial hypertension (PAH). The drug has been marketed specifically for this purpose under the trade name Revatio. Another drug -- bosentan -- is also approved for similar purposes.

The new research suggests that sildenafil may help all chronic obstructive pulmonary disease (COPD) patients -- even those not diagnosed with full-blown PAH -- who experience potentially dangerous pulmonary arterial blood pressure increases both at rest and following exercise.

The research was led by Dr. Sebastiaan Holverda of the department of pulmonary medicine at VU University Medical Center in Amsterdam, the Netherlands. Holverda and his VU colleagues were to present their findings Wednesday at a Salt Lake City meeting organized by the journal Chest.

According to the American Lung Association, COPD is actually a catch-all for two lung diseases that often strike in tandem -- chronic bronchitis and emphysema. In both cases, airflow is obstructed, impeding normal breathing.

Smoking is the leading cause of COPD, responsible for between 80 percent and 90 percent of all cases in the United States. More than 11 million Americans are estimated to have the illness, and more than 122,000 die from it each year. Women appear to be slightly more at risk than men.

There's no known cure for the disease, and medications primarily take aim at symptom relief and slowing the progressive disability the illness brings.

Pulmonary hypertension -- the incurable condition of continuous high blood pressure in the pulmonary artery located in the right ventricle of the heart -- is one of many serious complications that can strike COPD patients. PAH causes the artery, which is responsible for delivering blood from the heart to the lungs, to work harder than normal. A weakening of the heart muscle can ensue over time, increasing the risk of heart failure and even death.

The Dutch researchers noted that pulmonary hypertension is typically mild to moderate among COPD patients but is particularly aggravated while exercising.

Faced with the combined COPD-PAH threat, the Dutch team explored the potential benefit of treating at-risk chronic obstructive pulmonary disease patients with sildenafil both while at rest and during exercise. The drug works by shifting the activity of an enzyme called phosphodiesterase, reducing arterial blood pressure by dilating the smooth muscle of blood vessels that line the lungs. As these vessels expand, blood flow increases, the researchers explained.

The study authors focused on 12 patients who had been diagnosed with chronic obstructive pulmonary disease and were suspected of having PAH. Throughout the study, right heart blood pressure was tracked among all 12 patients by inserting a thin plastic tube into the pulmonary artery -- a procedure known as cardiac catheterization. Cardiac blood pressure was measured at rest and just after all the patients cycled for three minutes.

Then, the study participants were given 50 milligrams of oral sildenafil; 45 minutes later, resting and post-exercise blood pressure readings were taken again.

Holverda and his colleagues found that half the patients had PAH. But, both non-PAH and PAH patients experienced significant cardiac blood pressure increases when exercising.

Sildenafil appeared to control such increases after exercise, reigning in pulmonary blood pressure to markedly lower levels -- higher than at rest, but lower than non-medicated post-exercise readings. And, the non-PAH patients appeared to experience pulmonary blood pressure reductions after taking the drug, both while resting and exercising.

The authors concluded that the drug may help COPD patients -- whether they have developed PAH or not -- quickly control their pulmonary blood pressure in some situations.

Dr. Bartolome R. Celli, chief of pulmonary care at St. Elizabeth's Medical Center in Boston, applauded the Dutch study but called for more research.

"Pulmonary arterial pressure -- when it is elevated -- is a poor prognostic sign and reducing its levels should be of help," he said. "However, more testing is needed to see if those changes in pulmonary arterial pressure are translated into better clinical outcomes and not into any unwanted side effects.

http://www.nlm.nih.gov/medlineplus/news/fullstory_40520.html

<<< More..