The Food and Drug Administration has emerged from the recent fen-phen flap smelling more of fertilizer than flowers. This diet-pill disaster points up the limitations of our drug regulatory system.
When several doctors at the Mayo Clinic compared notes on patients with a distinctive heart valve problem, they discovered to their surprise that diet pills were a common denominator. A more exhaustive survey turned up 24 cases of heart valve problems in fen-phen (fenfluramine and phentermine) users.
Since their initial report, 75 additional cases have been reported.
A follow-up survey of 291 patients without obvious symptoms revealed that over 30 percent had signs of heart valve damage. The FDA was alarmed: "This is a much higher than expected percentage of abnormal test results."
One would have hoped that such a significant complication would have been detected and reported long before this. What this debacle demonstrates, however, is that none of the world's drug regulatory agencies have a good way to monitor medications that are out on the market.
Insidious side effects, such as heart valve problems, that may not cause symptoms for years might not be picked up. Physicians often rely on pharmaceutical company data to evaluate whether a patient's problem is drug related. If it has not been reported previously, they may not realize it is an adverse drug reaction.
For years researchers have been concerned about a possible link between estrogen and breast cancer. Millions of women take hormones to protect their bones and hearts as well as to relieve symptoms of menopause. The FDA cannot reassure physicians or patients that these medicines won't increase the risk of cancer.
Will other popular medications lead to similar complications as those of fenfluramine and Redux? These obesity drugs work primarily through serotonin, a neurotransmitter found throughout the body. Excess serotonin is thought to be responsible for heart valve complications similar to those found by the Mayo Clinic doctors.
But the FDA doesn't know if other drugs that affect serotonin may also have a deleterious impact on heart valves. Medicines such as Paxil, Prozac and Zoloft are taken by millions of people. Dr. Heidi Connolly, the lead author of the Mayo Clinic report, thinks heart problems from such drugs are unlikely, but that the question should be studied.
Until pressure is brought on the FDA to improve its surveillance system and protect the public better, drug disasters like this are bound to recur.
In their column, Joe and Teresa Graedon answer letters from readers. Write to them at Graedon's People's Pharmacy, P.O. Box 52027, Durham, N.C. 27717-2027, or e-mail to PHARMACY@mindspring.com.