Do you consume carcinogens? These cancer-causing chemicals are everywhere, but most people either don’t recognize them or can’t avoid them.
Obviously, cigarette smoke is one of the most notorious sources of carcinogens. Other compounds that have been linked to cancer include asbestos, benzene and formaldehyde. Prudent people try to avoid exposure to such chemicals.
But what about prescription drugs? It comes as a shock to both patients and physicians that many commonly prescribed medicines have been shown to cause cancer in animals.
Hormone replacement therapy (HRT) is among the most controversial medications in this regard. Estrogen can promote uterine as well as breast cancer. Millions of women have taken HRT to ease symptoms of menopause. How many have developed cancer because of this treatment is unknown.
A surprising number of other prescription medications have warnings in their labels about cancer. For example, the popular heartburn medicine omeprazole (Prilosec) causes abnormal cell growth and stomach tumors (carcinoids) in rats. No one seems to know whether this constitutes a problem for people.
Spironolactone (Aldactazide, Aldactone) is a blood pressure medicine that is sometimes prescribed for hormonal imbalances and facial hair growth in women. It causes tumors in rats.
Parents of children with eczema have been worried by reports that the prescription topical skin treatments, Elidel cream and Protopic ointment, are associated with lymphoma and skin cancer. The FDA has warned against using these drugs in children under two years of age. It also states that, “The long term safety of Elidel and Protopic are unknown.”
Such cautions are not reassuring; they leave patients and physicians in a quandary. The same is true for the rheumatoid arthritis injections Cimzia, Enbrel, Humira and Remicade. These very expensive bio-tech drugs have revolutionized the treatment of rheumatoid arthritis and Crohn’s disease. Last summer the FDA announced that it was investigating an association between these medications and the development of lymphoma or other cancers.
Another hugely controversial cancer connection has to do with cholesterol-lowering drugs. An article in the Journal of the American Medical Association (Jan. 3, 1996) warned over a decade ago that, “All members of the two most popular classes of lipid-lowering drugs (the fibrates and the statins) cause cancer in rodents, in some cases at levels of animal exposure close to those prescribed to humans.”
Recent research in the New England Journal of Medicine (Sept. 25, 2008) has cast a spotlight on Vytorin (ezetimibe and simvastatin), a different kind of cholesterol drug. Investigators noted a higher incidence of cancer in subjects taking this medicine, although a separate analysis concluded there was no risk.
An editorial in the Journal noted that these findings leave both doctors and patients uncertain about the safety of this medicine. That could also be said of dozens of other drugs that cause cancer in animals. The FDA ought to require studies that would clarify the risk, rather than asking Americans simply to ignore warnings of cancer.