Medication and Hypertension

Dr. Claude J. Lenfant, the director of the National Heart, Lung and Blood Institute, announced that he is appointing a committee of experts to develop new clinical guidelines for high blood pressure. The call to appoint the committee is a result of a recent study of over 42,000 individuals comparing the benefits of four types of drugs on major complications of high blood pressure. This study was the largest study ever of high blood pressure. The results were published in the December 18, 2002 issue of The Journal of the American Medical Association. It showed that a diuretic is superior to the newer, more expensive drugs in lowering high blood pressure and preventing its serious complications.

Individuals in the study were 55 years of age or older who had high blood pressure and at least one other risk factor for heart disease, like diabetes or cigarette smoking. All participants had blood pressure measured at or above 140/90. They were monitored, on average for five years. All individuals agreed to have a computer decide which drug they were to take. Four classes of drug were compared: a diuretic (chlorthalidone), amlodipine (sold as Norvasc), lisinopril (Zestril and Prinivil), an ACE inhibitor, and doxazonsin (Cardura), an alpha-adrenergic blocker.

Research indicated that the group who took the ACE inhibitors, when compared with the diuretic group, had, on average, about two points higher systolic pressure, with a 15% higher risk of stoke in all patients and a 40% higher risk for blacks. The calcium channel group had, on average, a systolic blood pressure about 1% higher and a 38% higher risk of developing heart failure. The doxazonsin arm of this study was stopped in March 2000 because people who took it had a 25% higher rate of heart disease and a double rate of heart failure compared to the diuretic.

One cannot tell from this study whether the diuretic had a positive effect or the other drugs had some negative effect. According to Dr. Michael Alderman, a hypertension expert at Albert Einstein Medical school: "We simply don’t know whether diuretics are doing more good, or less harm, than the calcium channel blockers and the ACE inhibitors."

Diuretics are generic drugs, are not heavily advertised, and cost pennies a day compared to the other drugs used to treat hypertension. Norvasc is expected to bring in nearly $4 billion in sales for Pfizer this year. Prinivil (lisinopril), sold by Merck & Company, lost its patent in June 2002 and sales are declining. AstraZeneca markets it as Zestril. In 1995, a study indicated that diuretics use had declined to 27% from 56% of hypertensive prescriptions from 1982 and 1992.

A 1998 study in The New England Journal of Medicine reviewed 70 medical journal articles that discussed calcium channel blockers and found that the authors of the overwhelming articles that supported the drug had financial relationships with drug manufacturers. Another article in The New England Journal of Medicine (NEJM) indicated that in 1996 there were no ads for diuretics in the NEJM and that calcium-channel blockers were the most heavily advertised drug in the journal.

Melody Peterson, wrote in her article in the New York Times (12/18/02): "Analysts say that the results of the government study that were announced yesterday were likely to have little effect on sales of the newer drugs, in part because drug makers will continue to urge doctors to prescribe their medicines as additional treatments for heart patients who need more than one drug to control their blood pressure."

Dr. Paul Whelton, a leader of the study is professor of epidemiology and senior vice president for health science at Tulane University recommended that doctors switch to diuretics or add them to existing regimens. It is not precisely known how diuretics reduce high blood pressure, despite their use for more than half a century.


Harold Rubin, MS, ABD, CRC, Guest Lecturer
posted December 25, 2002

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