Men with cardiovascular problems should think twice about using the anti-baldness drug minoxidil because it can raise their heart rate, the author of a new Canadian study warns.
"Topical minoxidil increases cardiac activity by 10%-20%," said Dr. Frans H. H. Leenen, an associate professor of medicine at the University of Toronto. He will present his findings next month in San Diego at a meeting of the American Society for Clinical Pharmacology and Therapeutics.
Since clinical trials of topical minoxidil for baldness began in the late 1970s, researchers have believed that not enough of the drug would be absorbed into the bloodstream to affect heart rate activity, Leenen said.
But he found otherwise. In his study, 20 men used minoxidil, a drug originally developed to treat high blood pressure, and 15 used a placebo. The increase in cardiac activity among the minoxidil users ranged from none to 50%, with 10%-20% the average.
"For a healthy subject, (topical minoxidil) is probably not a problem," Leenen said in a telephone interview. "The warning is for people with cardiovascular disease."
Upjohn Co., hoping for FDA approval for minoxidil as a baldness remedy, partially funded Leenen's study and disagrees with his conclusions. "We don't believe his conclusions are supported by his data," spokeswoman Kaye Bennett said in a telephone interview.
"You just don't get enough minoxidil into the bloodstream to cause cardiac effect," she added, pointing to a 1984 study of topical minoxidil by Dr. Zeev Vlodaver of the University of Minnesota Medical School, which found no effect on the heart.
"We saw no changes in cardiac output," confirmed Vlodaver, whose study of 135 men, about half of whom applied minoxidil, is unpublished.
So much for the "opposites attract" theory. A Denver research team says that Type A personalities--those competitive over-achievers who prefer the fast lane on the freeway and may be more likely to die of heart attacks--are most attracted to other Type A's.
And, you guessed it, the more deliberate, easygoing Type Bs tend to be most attracted to other Type Bs.
In the study by Joy L. Berrenberg and colleagues at the University of Colorado at Denver, 56 men and 56 women rated the attractiveness of persons described as Type A's or Type Bs. Type A's and Type Bs were each most attracted to their own personality type, the Denver team reported recently in the journal Psychological Reports.
"Type A persons gravitate toward those who share their hard-driving, competitive response style," the team noted. "The fact that they have many characteristics in common may serve to facilitate communication and enhance the probability that interactions will be reinforcing."
Keeping company with other Type A people, the researchers added, may also help Type A's achieve their own goals. And Type Bs may seek out other Type Bs, the researchers said, so they don't feel pushed beyond the limits of their comfort.
Zinc: Eyes Have It
Oral zinc may slow the deterioration of the central part of the retina, a leading cause of vision loss in the elderly, a team of researchers says.
In the study, reported in the current issue of the journal, Archives of Ophthalmology, 90 patients took 100-200 milligrams of zinc a day, more than five times the recommended daily allowance, and 84 patients received placebo treatment.
"We found a slowdown of vision loss in the zinc-treated group," said Dr. David A. Newsome, a professor of ophthalmology at the Louisiana State University Medical Center School of Medicine in New Orleans. Zinc appears to play a key role in the metabolism of the retina, noted Newsome, who will present the findings next week at a professional medical meeting in Tucson.
Consumers shouldn't self-prescribe zinc supplementation based on the study, said Newsome, who emphasized that the findings are preliminary. "Don't go out and dose yourself up on zinc," he warned. "Not yet."
The New Anesthesia
If you're scheduled for surgery requiring general anesthesia, so the old story goes, forget about your hair holding a permanent wave for months afterward. Don't be surprised if it falls out or becomes brittle. And expect strange lines or grooves to appear on your fingernails. All a result, some say, of the anesthesia.
"Old wives' tales," believes Dr. Caryl Guth , a San Mateo anesthesiologist and past president of the California Society of Anesthesiologists. "In the old days, when we used ether, there was some validity in that."
But with modern anesthesia, she said, problems with hair and nails are rare. If they occur, she said, they are probably a result of the physical and emotional stresses associated with the surgery. "Research has shown it's not due to the anesthesia itself.
"Now, within 24 hours almost all anesthetic agents in use today are out of the system," she added, "unless a patient has an abnormal reaction to the anesthetic."
Before a surgery requiring general anesthesia, patients should "discuss all physical problems with the anesthesiologist," Guth said.