SIBUTRAMINE - a medication to assist with weight management

Sibutramine (brand name Meridia) was approved in November, 1997, by the U.S. F.D.A. for use in weight management. Sibutramine was developed in the late 80's as an antidepressant. It acts in areas of the brain that control not only mood and sense of well-being, but also appetite. It is a monoamine reuptake inhibitor that increases the level of norepinephrine, serotonin, and to a lesser extent, dopamine, which is available to brain cells (neurons) by interfering with the reabsorption of these substances by the neurons that initially release them. Norepinephrine, serotonin, and dopamine are neurotransmitters (or messengers) in the brain that lead to stimulation of other neurons .

Sibutramine acts primarily by diminishing appetite, but may also slightly increase resting metabolic rate (the amount of energy consumed while resting), which leads to the ability to "burn" extra calories. However, some studies indicate that there is no increase in metabolic rate in individuals who use sibutramine. It is possible that sibutramine results in weight loss by other yet undefined mechanisms.

Unlike dexfenfluramine and fenfluramine, the medication does not cause release of serotonin from neurons. Tests done on humans show no evidence of valvular heart disease; and experiments done on animals show no evidence of neurotoxicity (brain damage), unlike the finding on test animals using the previously available medications fenfluramine and dexfenfluramine.

Clinical studies using sibutramine in conjunction with a low calorie diet, exercise, and behavior modification show that after 12 months, individuals placed on 15 mg. of sibutramine daily lost (on average) about 10 lbs (4.3 kg.) more than placebo-treated individuals. Some individuals, however, had a much larger weight loss.  As with all weight loss medications, weight loss plateaus may slowly increase despite continued use of the medication.

Sibutramine has other beneficial effects that are independent of the weight loss. Sibutramine lowers insulin levels (which should help correct some of the metabolic derangements associated with long-standing obesity) and significantly raises the level of HDL-cholesterol ("good cholesterol"), which may result in decreasing vascular complications in the future.

Like all medications, sibutramine has side effects. It can cause constipation, insomnia, and agitation.  Probably the most significant side effect is that it can raise blood pressure, sometimes significantly. Combining sibutramine with other anorexiant (appetite suppressant) medications is not recommended. Individuals treated with this medication should have regular medical follow-up; and the medication should be used as part of a comprehensive program that includes behavior modification, dietary intervention, and increased physical activity. Individuals who are preoccupied with food and feel hungry after large meals are the most appropriate candidates for sibutramine. Using sibutramine as sole therapy without the other components will likely result in minimal, if any, weight loss with the potential for serious medication-related side effects.

In summary, sibutramine is beneficial for selected individuals to assist with weight management. The medication must be combined with a reduced calorie diet, exercise, and behavior modification to achieve the desired results.

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