People who want to lose weight and keep it off may benefit from Meridia^® (sibutramine hydrochloride monohydrate). Meridia is a prescription drug that works by affecting certain chemicals in the brain, causing a sense of fullness and helping people to lose weight. As with any drug, there are possible side effects with Meridia. Some of the common side effects seen with this drug include insomnia, headaches, and constipation. Prior to taking Meridia, be sure to talk to your healthcare provider about your medical history and any other medicines you are taking (including vitamins and herbal supplements). You should seek medical attention immediately if you believe you have overdosed on Meridia.