Anorectic
The anorectics ( Greek anorectein: "have no appetite") or appetite suppressants , also appetite suppressants , are drugs with an appetite- inhibiting effect that are used for the purpose of weight loss . This effect is based on an inhibition of the hunger center or an influence on the satiety center in the hypothalamus of the brain . The best-known representatives of this group of substances are aminorex , cathine , ephedrine , phentermine , phenylpropanolamine (PPA) or norephedrine , fenfluramine , sibutramine , nicotine and rimonabant . Many of these drugs are used because of severe side effects such as: B. pulmonary hypertension and heart valve damage, no longer used therapeutically. A relatively new drug is the antidiabetic liraglutide , which has also been approved as an anorectic under the product name Saxenda since 2016. It is an incretin mimetic . Other incretin mimetics such as semaglutide in particular have a weight-reducing effect, but these have not (yet) been approved as anorectics.
pharmacology
Mechanism of action
The weight-reducing effect of anorectics is mainly based on inhibiting the hunger center or influencing the saturation center in the hypothalamus of the brain. Furthermore, anorectics with a sympathomimetic effect can contribute to weight loss by increasing the basal metabolic rate. At the molecular level, an increase in the neurotransmitters norepinephrine , dopamine and serotonin in the brain induced by these drugs is held responsible for the central appetite inhibition and the increase in the basal metabolic rate. Activation of the serotonin receptor subtype 2C (5-HT 2C ) is also discussed as a mechanism for the anorectic effect of classic appetite suppressants such as fenfluramine. Lorcaserin's anorectic effects are based on this mechanism .
An inhibition of the cannabinoid receptor CB 1 also leads to a significant inhibition of appetite. Receptors for opioids , neuropeptide Y , the appetite-suppressing hormone leptin and the appetite-stimulating hormone ghrelin are currently being investigated as further target structures for new anorectics .
However, the weight reductions observed are always limited to the period of intake. Study participants who experienced significant weight loss while taking anorectics returned to their original weight after they stopped taking them. The benefits of anorectics are therefore viewed as doubtful.
The relatively new incretin mimetics, of which liraglutide is mainly used as a slimming agent, have a different effect: They mimic the intestinal hormone GLP-1 and slow down gastric emptying, and as messenger substances they contribute to reducing the feeling of hunger and increasing the feeling of satiety.
Side effects
Due to numerous side effects, such as B. arterial hypertension , tachycardia , heart valve damage and due to their addiction potential these drugs came into disrepute. An observed association between the use of anorectic drugs and the increased occurrence of pulmonary hypertension led to the withdrawal of Aminorex, fenfluramine and dexfenfluramine. These side effects, like the anorectic effects, were associated with an increase in the concentration of neurotransmitters in the synaptic gap or an activation of serotonin receptors.
In competitive sports, many appetite suppressants are considered doping agents .
chemistry
Chemically, anorectics are mostly derived from amphetamine , but in contrast to this they hardly have any psychostimulatory effects. The best-known representatives of this group of substances or substances having an amphetamine underlying Phenylethylaminstruktur are Aminorex , phentermine , fenfluramine , dexfenfluramine , furfenorex and sibutramine . The herbal active ingredient ephedrine from Ephedra vulgaris also shows a structural relationship to the amphetamines.
In contrast, the cannabinoid receptor antagonist rimonabant is completely different from the amphetamine derivatives .
Herbal supplements such as For example, extracts of the South African succulent Hoodia gordonii , are advertised as an appetite suppressant. The effectiveness and especially the harmlessness of this extract is controversial.
Misuse
Products that are freely available on the Internet and that are labeled as herbal may contain synthetic drugs in high doses and may be too expensive. U. lead to severe symptoms of intoxication.
Individual evidence
- ↑ Hildegard Kaulen: Explosive appetite suppressants. In: FAZ.net . July 19, 2011, accessed October 13, 2018 .
- ↑ Curzon G, Gibson EL, Oluyomi AO: Appetite suppression by commonly used drugs depends on 5-HT receptors but not on 5-HT availability . In: Trends Pharmacol. Sci. . 18, No. 1, January 1997, pp. 21-5. PMID 9114726 .
- ↑ Bays HE: Lorcaserin and adiposopathy: 5-HT2c agonism as a treatment for 'sick fat' and metabolic disease . In: Expert Rev Cardiovasc Ther . 7, No. 11, November 2009, pp. 1429-1445. doi : 10.1586 / erc.09.123 . PMID 19900026 .
- ↑ Müller, Dieter et al .: Sibutramine in Chinese slimming capsules: A case series . In: Dtsch Arztebl Int . No. 106 (13) , 2009, pp. 218-222 ( Article ).
