Wednesday, 3 September 2008

Allopurinol May Lower Blood Pressure In Teens With Hypertension

� The drug zyloprim, which lowers uric acid levels, appears to reduce blood pressure level in adolescents with fresh diagnosed hypertension, according to a preliminary report in the August 27 publication of JAMA.


Hypertension is commonly associated with hyperuricemia (elevated blood level of uric acid, a by-product of normal chemical processes in the body and found in the piddle and pedigree). Early research suggested uric acid had a causal role in hypertension, but an natural elevation of uric acid in hypertension could be a consequence of several factors, and hyperuricemia is non considered a true hazard factor for hypertension, according to background information in the article. Recent studies have challenged this impression, including evidence supporting a causal part of uric acid in hypertension, as indicated from experimental studies in science laboratory animals.


Daniel I. Feig, M.D., Ph.D., of the Baylor College of Medicine, Houston, and colleagues conducted a randomised, placebo-controlled "crossing over" trial to determine whether lowering uric acid levels with the drug zyloprim would reduce blood pressure level (BP) in hyperuricemic adolescents (age 11-17 years) with newly diagnosed hypertension. Thirty patients were randomly assigned to get either allopurinol or placebo, twice day-after-day for four weeks. This was followed by a two week "washout" point during which the patients received neither allopurinol nor placebo, after which they received the other therapy (allopurinol or placebo) they had not received sooner, for tetrad more weeks.


Allopurinol treatment was associated with a significant decrease in casual and ambulatory systolic and diastolic BP. The median decrease in casual BP during zyloprim treatment was -6.9 mm Hg for systolic and -5.1 mm Hg for diastolic BP; for placebo, the various changes were -2.0 and -2.4. The average changes in 24-hour ambulatory BP during zyloprim were -6.3 mm Hg, systolic; -4.6, diastolic BP. Systolic BP increased slightly during the placebo phase by 0.8 mm Hg and diastolic BP slightly decreased by 0.3. The decrease in ambulatory BP directly correlated with zyloprim treatment. Twenty of the 30 participants achieved normal BP by casual and ambulatory criteria during the allopurinol form, whereas only 1 of 30 achieved normal BP during the placebo phase.


"The results of this study represent a potentially new curative approach, that of control of a biochemical suit of hypertension, rather than nonspecifically lowering elevated BP. Although not representing a fully developed therapeutic strategy, this report raises an alternative strategy that may prove to be more effective than currently uncommitted options," the authors spell.


"Despite these findings, this clinical trial is a small i and allopurinol is not indicated for the treatment of hypertension in adolescents or other populations. The potential inauspicious effects of allopurinol, including gastrointestinal complaints and especially Stevens-Johnson syndrome [a severe, allergic reaction], make allopurinol an untempting alternative to available antihypertensive medications. More clinical trials are needed to determine the reproducibility of the data and whether it can be generalized to the bigger hypertensive population. Nevertheless, the observation that lowering uric acid can reduce BP in adolescents with new diagnosed high blood pressure raises intriguing questions nearly its part in the pathogenesis of hypertension," the researchers conclude.


(JAMA. 2008;300[8]:924-932.)


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