Health Highlights: July 1, 2005
FDA Scientist Warned of Viagra-Blindness Link: Report Some Defibrillator Recalls Classified as Most Serious Pfizer Halts Efforts on HIV, Asthma Drugs Officials to Check Texas Herd for More Mad Cow Disease FDA: Green Tea Won't Reduce Risk of Breast or Prostate Cancer
Here are some of the latest health and medical news developments, compiled by the editors of HealthDay:
FDA Scientist Warned of Viagra-Blindness Link: Report
More than a year before news broke that the erectile dysfunction drug Viagra was possibly linked to a rare form of blindness, a U.S. Food and Drug Administration safety officer alerted superiors to the possibility, the Washington Post reported Friday.
The unidentified safety officer had been monitoring adverse event reports and told supervisors in April 2004 that doctors and users should be warned of the findings, she reportedly told congressional investigators. But the FDA issued no public warnings or changes to the drug's label until a scientific journal reported last month of the possible link, the newspaper said.
On Monday, Pfizer issued a statement saying it had no evidence in trials involving 13,000 people of a link between Viagra and a form of blindness called non-arteritic anterior ischemic optic neuropathy (NAION). That followed a report in last month's Journal of Neuro-Ophthalmology, which examined seven cases where men suffered NAION within 36 hours of taking Viagra, the Post said.
The FDA has said it has 38 reports of NAION among Viagra users and five additional reports among users of other impotence drugs, the newspaper said.
In response to the latest report, Consumer's Union, publisher of Consumer Reports, renewed a call for congressional reform of the FDA's drug monitoring system. "The fact the agency responsible for drug safety knew for a year that Viagra was linked to blindness, but did nothing with that information, is a clear indication that the system is broken," a spokesman said in a prepared statement.
Some Defibrillator Recalls Classified as Most Serious
The U.S. Food and Drug Administration has applied its most serious recall rating to two Guidant Corp. defibrillator models that have been found to malfunction.
Guidant, on June 17, announced that its defibrillators had been linked to two deaths in which the devices didn't work properly.
The FDA has given Class 1 recall status to Prizm 2 DR (made before April 16, 2002) and Contak Renewal 1 and 2 defibrillators (made before August 26, 2004), both the FDA and the company announced Friday. A recall in this category involves a malfunctioning device that could cause "serious adverse health consequences or death," the agency said in a statement. The firm's own investigation found these devices can shortcircuit while attempting to deliver an electric shock to the heart. Some 42,000 devices are affected, of which 20,600 are still implanted, the FDA said.
A less severe class 2 recall status was given to a number of other Guidant models, including the Ventak Prizm AVT, Vitality AVT, Renewal AVT, Renewal 3 and 4, Renewal 3 and 4 AVT, and Renewal RF, the FDA said. While faulty products in this category could cause medically reversible problems, the "probability of serious adverse health consequences is remote," the agency said. Memory errors and component failures are possible among the more than 60,000 devices in this category that have been produced.
As a precautionary measure, the FDA said, Guidant has recommended that doctors discontinue implanting these devices until further notice. Among patients with devices that have already been installed, the company recommends that they continue to visit their doctors at normal three-month intervals and immediately report any possible sign of malfunction.
Pfizer Halts Efforts on HIV, Asthma Drugs
Pfizer is abandoning development of an experimental drug for the virus that causes AIDS after studies showed the medicine fared no better than existing treatments, the Associated Press reported Friday.
Pfizer said capravirine did not significantly boost the effectiveness of standard triple-drug HIV therapies, the wire service reported. The drugmaker said it would return rights to the experimental medication's Japanese developer.
Separately, Pfizer said it was also discontinuing development efforts with a German drugmaker for an asthma and lung disease drug called Daxas. Pfizer cited unsatisfactory patient recruitment efforts, the AP reported.
Officials to Check Texas Herd for More Mad Cow Disease
Over the next few weeks, agriculture officials will check cattle in the Texas herd that produced the first homegrown case of mad cow disease in the United States. The goal: To pinpoint animals born within a year of the infected cow, as well as offspring born to the infected cow within the past two years.
The survey is being conducted to determine if other cattle in the herd may be infected with mad cow disease, the Associated Press reported.
Authorities said Thursday that the infected 12-year-old beef cow was born, raised and used for breeding on a single ranch and never left the ranch, which has not been identified. Information about the size of the herd has not been released.
It's believed the cow contracted the brain-wasting disease from contaminated feed that contained cow parts. The cow was born about four years before a 1997 ban on the use of cow parts in cattle feed, the AP reported.
Earlier this month, the Texas State Animal Health Commission put a hold on the ranch's cattle after tests indicated a case of mad cow disease in the herd. The infected cow never entered the human food supply, officials said.
Green Tea Doesn't Reduce Risk of Breast or Prostate Cancer: FDA
It's highly unlikely that drinking green tea reduces the risk of breast or prostate cancer, the U.S. Food and Drug Administration said Friday.
An FDA review of claims about green tea and cancer also concluded that existing evidence does not support qualified claims linking drinking green tea and a reduced risk of any other type of cancer.
In a news release, the FDA said: "Two studies do not show that drinking green tea reduces the risk of breast cancer in women, but one weaker, more limited study suggests that drinking green tea may reduce their risk. Based on these studies, FDA concludes that it is highly unlikely that green tea reduces the risk of breast cancer."
A similar statement downplayed green tea's role in preventing or reducing the risk of prostate cancer.