Long-term safety of anti-obesity agents
In appropriate patients, along with diet modification, daily exercise, and proper nutrition, I frequently prescribe anti-obesity medications for 6-12 months. Are there any adverse effects of using these medications long term, i.e., three, five, or 15 years?
—Gowri R. Rocco, MD, Wayne, N.J.
Drug therapy may be useful when combined with diet, exercise, and behavioral modification, but the long-term effects of these medications are not yet known. The maximum duration of published treatment results is only two years for sibutramine (Meridia) and four years for orlistat (Xenical). In a meta-analysis of pharmacologic therapy of obesity, five trials of sibutramine found that at 44-54 weeks, patients treated with sibutramine weighed on average 4.45 kg less than those taking placebo (Ann Intern Med. 2005;142:532-546). However, sibutramine is a sympathomimetic agent that has the potential to increase BP and should generally be avoided in patients with CAD, congestive heart failure, and cardiac arrhythmias. In the four-year double-blind, randomized, placebo-controlled trial with orlistat, 3,305 patients were randomized to placebo or orlistat (Diabetes Care. 2004;27:155-161). Mean weight loss was significantly greater with orlistat than placebo at one year (10.6 vs. 6.2 kg, P <.001) and remained so at the end of the four-year study (5.8 vs. 3.0 kg, P <.001). However, GI side effects of orlistat (cramps, flatus, fecal incontinence, oily spotting) may limit compliance. Despite the current lack of long-term data, the results of these studies are encouraging, and it may be appropriate to continue these agents longer if you and the patient agree after a discussion about what evidence currently exists.
—Daniel G. Tobin, MD (103-16)