The Pregnant Mare's Lesson

In a former British colony healers believed the conventional wisdom that a distillation of fluids extracted from the urine of horses, if dried to a powder and fed to aging women, could act as a general tonic, preserve youth, and ward off a variety of diseases.  The preparation become enormously popular throughout the culture, and was used widely by older women in all strata of society.  Many years later modern scientific studies revealed that long-term ingestion of the horse-urine extract was useless for most of its intended purposes, and that it caused tumors, blood clots, heart disease, and perhaps brain damage.

The quote and the title of the post are from Jerry Avorn's excellent new book, Powerful Medicines.  Can you guess why I like this quote and Avorn's book?  Read the extension.

Here again is Avorn:

The former colony is the United States, the time is now; the drug is the family of hormone replacement products that include Prempro and Premarin (manufactured from pregnant mare's urine, hence its name.)  For decades, estrogen replacement in postmenopausal women was widely believed to have "cardio-protective" properties; other papers in respected medical journals reported that the drugs could treat depression and incontinence, as well as prevent Alzheimer's disease.  The first large, well-conducted, controlled clinical trial of this treatment in women was not published until 1998; it found that estrogen replacement actually increased the rate of heart attacks in the patients studied.  Another clinical trial published in 2002 presented further evidence that these products increased the risk of heart disease, stroke and cancer.  Further reports a year later found that rather than prevent Alzheimer's disease, the drugs appeared to double the risk of becoming senile.  The studies resulted in a reduction, but not an end, to the long-term use of these products.