Very few weight-loss medications have been approved for use in children, as the risks of taking them long term are still unknown and their effect on weight loss and maintenance in adolescents is unclear. They may also be viewed as a Band-Aid solution: Unless behavioral and lifestyle changes are made, once the medication is stopped, the weight will return. For these reasons, most doctors prefer to manage childhood obesity with a combination of behavioral and lifestyle changes unless a child needs treatment for a related health problem, such as diabetes or sleep apnea.  Orlistat (Xenical) can be used in adolescents over age 12 and works by preventing the absorption of fat in the intestines; sibutramine (Meridia) is approved for those over 16 and alters the brain's chemistry to make the body feel fuller more quickly. Alli, the reduced-strength over-the-counter (nonprescription) version of orlistat, is not approved for individuals under age 18. Be aware that these drugs also often cause extremely unpleasant and potentially embarrassing gastrointestinal symptoms like gas and loose stools.