News

Healthy men who took Viagra, Cialis see fine: study

Healthy men who took Cialis or Viagra daily for six months did not develop any significant vision problems, U.S. researchers said on Monday in a company-funded study aimed at addressing concerns about the popular impotence treatments.

Pfizer Inc's Viagra or sildenafil and Eli Lilly and Co's Cialis or tadalafil treat impotence by increasing blood flow to the genitals, but some men taking the drugs have reported blurred vision, blue-tinged vision or altered light perception.

The drugs work by blocking the action of the enzyme phodiesterase type 5 or PDE5 on the blood vessels in the penis. But PDE5 inhibitors may also act on blood vessels in the retina, which could explain some of the reports of vision problems.

To test this, a team led by Dr. William Cordell of Lilly Research Laboratories in Indianapolis and colleagues conducted a randomized study to look for changes in the retina among men taking Viagra or Cialis.

They studied 244 healthy men or those with mild erectile dysfunction aged 30 to 65 who had no vision problems. Of these, 85 took 5 milligrams of Cialis, 77 took 50 milligrams of sildenafil and 82 took a dummy pill daily for six months.

The men underwent comprehensive eye exams, including electroretinography, a test to measure the electrical response of the light-sensitive cells in the eye, before, during and after treatment.

Among the 194 men who completed the study, the researchers found no significant differences between treatment and placebo groups on electroretinography, visual function tests, measurements of pressure within the eyeball or assessments of the anatomy of the eye.

“Our results indicate that there is no cumulative damage or effect of clinical significance,” for the studied doses of either drug, the researchers wrote in the Archives of Ophthalmology.

They said their study was limited because the doses used were lower than some other studies that did find retinal changes. And they said the results could not be generalized to men with eye problems, who were excluded from the study.

Viagra and Cialis each had global sales of more than $1 billion in 2008.

Eli Lilly designed and paid for the study, which did not evaluate Bayer AG's Levitra or vardenafil, a similar drug.

(Reporting by Julie Steenhuysen; Editing by Michael Conlon and Eric Walsh)
Reuters Health

The erectile dysfunction drug Viagra may have found a new, potentially life-saving use in hospital pediatric intensive care units, researchers report.

Australian researchers gave the drug to 15 babies with congenital heart disease who were being weaned from inhaled nitric-oxide therapy, a treatment that ICUs use to help these infants survive.

The researchers found that a dose of Viagra prevented a common life-threatening complication called rebound pulmonary hypertension. They also found that it significantly reduced the amount of time the babies spent on mechanical ventilation and in the ICU.

“Rebound pulmonary hypertension is a very common problem,” said Dr. Steven Abman of The Children's Hospital in Denver, who was not part of the study. “This is the most rigorous study that's ever been done to demonstrate that Viagra can prevent this complication.”

The study results were published in the November issue of the American Journal of Respiratory and Critical Care Medicine.

Viagra is useful for treating both erectile dysfunction and preventing rebound pulmonary hypertension because it affects pathways involved in both conditions.

“Viagra enhances the body's levels of cyclic-GMP, a naturally occurring substance that relaxes arteries and reduces their pressure, which is why its primary indication is for men with erectile dysfunction,” explained the study's lead researcher, Dr. Lara Shekerdemian of the Pediatric Intensive Care Unit at the Royal Children's Hospital in Melbourne.

“However, cyclic-GMP is abundant in the lungs and is the molecule via which nitric oxide acts as a dilator of pulmonary arteries,” Shekerdemian said. “That's why its use was explored in the setting of pulmonary hypertension in the newborn.”

In the study, Shekerdemian and colleagues gave a single dose of Viagra to 15 infants with congenital heart disease who were undergoing withdrawal from nitric oxide, which is used to relax pulmonary blood vessels in mechanically ventilated lungs. Another 14 infants undergoing withdrawal were given placebo.

None of the Viagra-treated infants developed rebound pulmonary hypertension compared to 10 of the placebo-treated infants. After more than 24 hours, all of the infants who developed rebound hypertension were given Viagra during a subsequent and successful attempt to wean them from nitric oxide.

The Viagra-treated infants also spent less total time on a mechanical ventilator than the placebo-treated infants — a little over 28 hours compared to 98 hours — and had a considerably shorter stay in the intensive care unit (47.8 hours vs. 189 hours).

“Although we expected to see an avoidance of rebound, we were not expecting to see these additional benefits,” Shekerdemian said. “Any intervention that smoothes their course in the intensive-care unit would have at least a short-term positive influence on their recovery from their underlying condition.”

Unless there's some reason for not using Viagra, Shekerdemian said that it should be routinely used as infants are weaned from nitric oxide. “We certainly do so now in our pediatric intensive-care unit,” she said.

Many hospitals are already doing just that. “I think it already has become standard clinical practice, because the idea of using Viagra for this is not new,” Abman said. “What's new is that this is the first study to look at it with a nice protocol in which they randomized patients and controlled in a blinded way. So it verifies what we've already been doing in clinical practice.”

Shekerdemian and her team are now conducting a similar study in the Royal Children's Hospital's Neonatal Intensive-Care Unit to see if Viagra can prevent rebound pulmonary hypertension in premature infants.

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.”

Viagra and the Mountains

Researchers Say the Drug May Help Performance at High Altitude, Help Soldiers Fight in Afghanistan

As the commercials continually remind us: Viagra is all about performance.
Now it turns out, that's not just referring to in the bedroom.
Researchers say the drug, approved for erectile dysfunction, could eventually help some athletes train at high altitudes and soldiers fight in the mountains of Afghanistan.
In a study at Stanford University, some volunteers riding stationary bicycles and breathing through masks to simulate the low oxygen conditions found at 12,700 feet, improved their times for six kilometers by an average of 39 percent after taking Viagra.
The drug, which became an instant blockbuster for Pfizer in 1998, works by causing blood vessels to relax - not only in the penis but in the lungs.
Last year, the company won approval for the drug, also known as sildenafil, to treat a medical condition called pulmonary hypertension, or high fluid pressure in the lungs. Pulmonary hypertension is also one of the effects of exercising in oxygen-poor environments such as high altitudes.
“It provides a pretty clear advantage to some people,” said Annie Friedlander, the senior author of the study, which appears in the Journal of Applied Physiology.
It does not help everyone. Only four of the 10 riders saw their times improve - 10 minutes, 48 seconds with Viagra compared to 15 minutes when they took a placebo.
Researchers are not certain why only some volunteers responded to the drug, but they noticed that they were the ones whose times had suffered the most at high altitudes. Viagra, it seems, allowed them to make up the performance they had lost.
None of the riders saw any improvement from the drug at sea level, and none reported an erection during the trials.
The next step: The U.S. military plans to test Viagra, at high altitude, on about a dozen soldiers later this summer.

Women can benefit from Viagra

Viagra may help some women
Women can benefit from taking the impotence drug Viagra, scientists have claimed.

Research by a team from the University of Boston has found that the drug can benefit women who have had a hysterectomy or who have gone through the menopause.
In both cases, women experience a loss of production of female hormones that can lead to sexual problems, such as loss of sensation and lubrication.
Dr Jennifer Berman tested the drug on 17 women who had either had a hysterectomy or gone through the menopause.
Each woman got either Viagra or a dummy pill, and three months later the women who got Viagra were switched to a placebo and the women who had been given sugar pills got Viagra.
Dr Berman and the patients did not know which woman got which pill until the end of the study.
Viagra, whose technical name is sildenafil, works by increasing the effects of nitric oxide, a common body chemical, which in turn gets more blood flowing into the genitals.
Dr Berman, who will present her findings to a meeting of the American Urological Association, said: “Sildenafil did appear to significantly increase blood flow and pH and pH is an indicator of lubrication.”
“Subjectively, with regard to lubrication, sensitivity, the ability to have orgasm, and satisfaction, the women noted a significant difference.”

Emotional problems
Dr Berman has carried out another study at Boston University with 48 women, aged 22 to 71.
While not so carefully controlled - the women all got Viagra and knew it - there was a statistically significant difference.
She said: “It does appear to be Viagra because there are physiological changes that can't be faked.”
However, Viagra failed to work for women in the second study who had psychological problems with sex.
These included poor body image, a history of sexual abuse, or marital trouble.
Dr Berman said: “Those women don't respond to Viagra or any drug.
“Although there are physiological, medical reasons why women have sexual complaints, there are emotional and relational consequences to sexual dysfunction that are relevant to women.”
She added that it was more difficult to tell if a woman had sexual problems.
“While men can define their sexual function in terms of rigidity, for women it doesn't work that way,” she said.
Pfizer, the manufacturers of Viagra, say that seven million prescriptions have been written for the drug worldwide since its launch last year.