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Drugs for the treatment of obesity
Drugs for the treatment of obesity
As for obesity drugs for long-term use only approved sibutramine and orlistat (orlistat). With the exception of orlistat, which inhibits the absorption of fats from food, and all other medications have anorectics (appetite-reducing effect. Anorectics preparations promote rapid emergence of satiety (feeling of stomach fullness during a meal, which regulates food intake) or saturation (the intensity of feelings of hunger some time after the meal, which regulates the frequency of meals), or both of them through a system of monoamines (norepinephrine, serotonin and dopamine) in the hypothalamus (part of the brain stem). anorectics All drugs, except for mazindol, are derivatives of amphetamine precursor ß -phenylethylamine.
Methamphetamine causes drug dependence and must be withdrawn from use, while other derivatives of amphetamine have been chemically modified in order to reduce their adverse effects. Monoamine neurotransmitters are synthesized from tyrosine and accumulate in the granules whose contents are released into the interneuronal cleft between the presynaptic and postsynaptic nerve. Most of monoamines released as interneuronal gap is captured back into the presynaptic nerve terminal part, after which they are either destroyed or re-packaged into pellets for the next release. A small amount of the released monoamine binds to postsynaptic receptors, thus contributing to, the transfer of signal from one nerve to another. Of anorectics drugs most often prescribed to patients phentermine and sibutramine. Phentermine stimulates the release of norepinephrine and dopamine from nerve endings.
Sibutramine inhibits the reuptake of norepinephrine, serotonin and, to a lesser extent, dopamine. Sibutramine has a greater effect on satiety and may also cause a person a slight increase in the rate of metabolism for several hours after ingestion.
Tool that reduces the absorption of fats in the small intestine (Xenical or orlistat) - a synthetic derivative lipstatina, product life mold fungus Streptomyces toxytricini, which inhibits most kinds of lipases (enzymes rasschiplyayuschih fats) in mammals. Once in the gastrointestinal tract associated with orlistat stomach, pancreatic lipases and blocks them and karboksiesterazoy effect on triglycerides from food (fats) and esters of vitamins. Inhibition (inhibition) inhibits fat absorption and the formation of molecular chains of the absorption of long chain fatty acids, cholesterol and fat-soluble vitamins.
The percentage of fat absorption deterioration is clearly associated with a dose of Xenical. Using the drug at a dose of 360 mg per day (120 mg 3 times daily with meals), approximately 30% of triglycerides derived from a chair, which corresponds to almost the maximum value at the plateau (stabilization effect). That is, the reception while eating at a dose of Xenical 120 mg over, most likely, will not lead to further diminish intake received from food fats.
Fat slowly passes through the stomach, while Xenical - Faster. That is, when taking Xenical with meals, it can bind only the lipase, which are released when the first portions of food, and cease to have effect when the fat containing food enters the duodenum.
Strengthening the physical interaction between ksenikalom and fats from food increases its activity against deterioration of fat absorption. An experimental 4-hour introduction of Xenical in the duodenum in the use of portions of food containing 10 grams of fat, and the simultaneous introduction of four-hour fat emulsion containing 30 g fat, resulting in 95% inhibition of the hydrolysis of triglycerides. Absorbed less than 1% of Xenical, which fell into the gastrointestinal tract, so it does not have a systemic effect on lipase.
