Review: Weight-loss Drug Raises Blood Pressure

A new review of existing research confirms that a weight-loss drug raises blood pressure, posing a risk to obese patients who hope to reduce hypertension by shedding pounds.

Many doctors assume that patients automatically lower their blood pressure when they become thinner, but that is not necessarily the case when they use drugs to lose weight, said review lead author Dr. Andrea Siebenhofer.

In the big picture, “anti-obesity drugs are no wonder pills and should be prescribed only if patients beg doctors for some tablets which help them to lose some weight,” said Siebenhofer, a researcher at the Medical University of Graz in Austria.

The review authors examined research regarding three weight-loss drugs — orlistat, sibutramine and rimonabant. They looked for studies that lasted at least six months and compared patients with high blood pressure who took one of the drugs to those who took a placebo.

The analysis appears in the latest issue of The Cochrane Library, a publication of The Cochrane Collaboration, an international organization that evaluates medical research. Systematic reviews draw evidence-based conclusions about medical practice after considering both the content and quality of existing medical trials on a topic.

The researchers found no studies that met their criteria for patients who took rimonabant, known by the brand name Acomplia.

The drug is not available in the United States; in 2007, the Food and Drug Administration declined to approve its sale and asked its manufacturer to provide more information about its safety. In 2008, the manufacturer agreed to suspend its sale in Europe, amid reports that it heightened the risk of suicidal thoughts.

The review authors did find four studies examining each of the other two drugs, orlistat and sibutramine.

Orlistat, known by the brand names Xenical and Alli, is both an over-the-counter and a prescription drug in the United States. Sibutramine is a prescription drug sold under the brand name Meridia.

The researchers conducted a meta-analysis by combining the studies and adjusting the statistical results to account for their sizes.

In those treated with orlistat, blood pressure fell by an average of 2.5 mm Hg systolic and 1.9 mm Hg diastolic.

However, the diastolic blood pressure levels of patients who took sibutramine rose by 3.2 mm Hg, according to the meta-analysis.

Systolic blood pressure is the top number in a blood-pressure reading (like 120/80) while diastolic is the bottom number.

The review of sibutramine research had some limitations. The review authors only looked at two of the four studies into the drug because they believed the other two did not meet the criteria they had set for inclusion in the meta-analysis.