Diuretics effective as second-line therapy for hypertension

Oct 13, 2009

Lisa Nainggolan
Vancouver, BC - Diuretics, when given as second-line therapy to treat hypertension, reduce blood pressure to about the same extent as when they are used as first-line treatment, a new review shows

The results also indicate that the BP-lowering effect of diuretics depends on the dose used but is independent of the type of first-line agent used; the latter being an unexpected finding, say Jenny MH Chen (University of British Columbia, Vancouver) and colleagues in a report published October 7, 2009 in the Cochrane Database of Systematic Reviews.

Hydrochlorothiazide (HCTZ) was the diuretic used in 92% of the studies included in this review, and it has recently been the subject of some criticism.

But Chen told heartwire she did not believe this to be warranted: "We believe that the recent criticism of HCTZ is misguided and not an accurate reflection of the evidence. Our review adds to the body of evidence demonstrating that HCTZ is indeed effective in lowering trough blood pressure; it can be given as a single daily pill and is an excellent drug choice for patients as the first or second drug."

Dr Franz Messerli (St Luke's Roosevelt Hospital, New York, NY), the lead author of a recent meta-analysis that concluded that HCTZ is a "paltry" antihypertensive at the usual doses prescribed (12.5-25 mg), told heartwire: "The meta-analysis of Chen et al is thorough and comprehensive, as one expects from this well-experienced team." But, he says, it is outcomes that are important, not merely lowering blood pressure, and there are no outcome data as yet for HCTZ 12.5 to 25 mg. "All outcome data with so-called 'thiazides' are based on chlorthalidone and indapamide."

In conclusion, she told heartwire: "Thiazide diuretics are recommended as first-line agents in the treatment of hypertension" because "the evidence for the other classes of drugs such as beta blockers, ACE inhibitors, and CCBs, for example, is less robust.

"However, Messerli begs to differ: "The authors get carried away by stating that thiazide diuretics are recommended as first-line agents because the evidence for other drug classes is less robust," but they "seem to forget that there are no outcome data for HCTZ in doses of 12.5 to 25 mg. Most important, we should remember that outcome data comparing combination therapy are scarce. "

The only convincing study is ACCOMPLISH, in which a fixed combination of amlodipine and benazepril was clearly superior to a fixed combination of benazepril and HCTZ with regard to morbidity and mortality. Since BP was lowered to the same extent in both treatment arms, this would indicate that antihypertensive effect per se is of limited value when assessing combination therapy," he concludes.

Fuente: theheart.org