An herbal remedy that had been popular among prostate cancer patients was tainted with three synthetic drugs, according to an analysis of batches of the remedy made between 1996 and 2001. The product, called PC-SPES, has since been recalled by its California-based manufacturer, BotanicLab, which has gone out of business.
Researchers became curious when seriously ill patients taking PC-SPES began to fare better than expected. However, lab experiments showed that the known herbal ingredients in PC-SPES all failed individually to have much success killing prostate cancer cells, says study coauthor Robert Nagourney, a medical oncologist at the University of California, Irvine and Rational Therapeutics in Long Beach.
Nagourney and his colleagues chemically analyzed PC-SPES and found diethylstilbestrol, or DES, a synthetic estrogen that has been used as an anticancer drug but can cause heart problems. They also found the anti-inflammatory drug indomethacin in the remedy and the blood thinner warfarin. All three drugs normally require a prescription. The researchers report their findings in the Sept. 4 Journal of the National Cancer Institute.
As an over-the-counter remedy, PC-SPES posed a health hazard and was rightfully removed from the shelves, Nagourney says. Ironically, he says, the progress seen in some patients taking it suggests that the drug combination might prove valuable as part of an anticancer regimen and should be investigated.
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