What does Anorectic mean?
The anorectic adjective is attributed to any substance capable of extinguishing the appetite stimulus. The potential usefulness of these antifame drugs in the treatment of obesity is a particularly delicate and debated topic, the subject - over the years - of increasing limitations and prohibitions.
Amphetamine anorectics
The anorectic action is typical of amphetamines and their derivatives: amphetamine, methamphetamine, benzfetamine, fendimetrazine, diethylpropion, mazindol, phentermine, phenylpropanolamine, amfepramone, dexfenfluramine.
Since the use of amphetamine-like anorectic drugs is burdened by important side effects : irritability, anxiety, euphoria, depression, confusion, headache, insomnia, tremor, palpitation, tachycardia and arrhythmia, their therapeutic use has been greatly reduced in years. However, many of these substances are still the subject of intense trade in the black market, also available on the web for the vast public of overweight people who are looking for a quick and painless solution to the problem, often unaware of the dangers deriving from the use of these substances and of the real reasons that have forced the withdrawal from the market:
- phenylpropanolamine : increases the risk of hemorrhagic stroke, especially in women;
- fenfluramine: while not presenting the side effects typical of amphetamine derivatives, it increases the risk of suffering heart valve injuries:
- fendimetrazine: the last of the anorectics to retire in August 2011, presents the side effects typical of amphetamine derivatives: irritability, anxiety, tachycardia, palpitations, arrhythmias, tremors and hypertension; in addition to this, the excessive euphoria and sense of well-being deriving from the first assumptions are gradually transformed into depression as tolerance and dependence arise with continued use.
Anti-depressive anorectics
Among the anorectic drugs we do not find only the amphetamine derivatives, which exert their action stimulating the release of catecholamines or activating the receptors, but also antidepressants of common use. These drugs work by blocking the reabsorption of norepinephrine, dopamine and serotonin at the level of the central nervous system synapses, enhancing the signal. Among all, it is above all the so-called serotonergic drugs that are studied and used as anorectics; in fact, serotonin is able not only to promote good humor and tranquility, but also to decrease food intake. With reference to this last point, it is believed that serotonin causes an early onset of the satiety signal, reduces the palatability of food and the total amount of food ingested, reduces carbohydrate ingestion and increases protein ingestion without affecting fat intake and meal frequency.
Compared to amphetamine derivatives, which exert their own slimming effect also through the general stimulation of body metabolism (greater energy expenditure), serotonergic drugs do not have this effect and are therefore relatively free from side effects such as anxiety, tremors, sweating, tachycardia, etc. The most commonly used serotonergic drugs for anorectic activity are fenfluramine and dexfenfluramine, banned as far back as 1997 for serious side effects, such as pulmonary hypertension and heart valve alteration. Fluoxetine and Sertraline are instead drugs with anorectic effect more contained and short term, used in therapy primarily as antidepressants.
Sibutramine
A particularly well known anorectic drug, capable of acting as both amphetamine derivatives (noradrenergic effect), and as serotonergic is sibutramine (Ectiva, Reductil, Reduxade, Meridia), recently withdrawn from the market due to unfavorable side effects: dry mouth, constipation, headache, insomnia, hypertension, tachycardia, stroke and heart attack.
Rimonabant
Another drug with anorectic action withdrawn from the market is rimonabant (Acomplia, Zimulti), a cannabinoid receptor antagonist. It works by blocking a specific type of receptor, type 1 cannabinoid receptors (CB1). These receptors are found in the nervous system and are part of the system used by the body to control food intake. Receptors are also present in adipocytes (adipose tissue). Consequently, rimonabant reduces food intake and promotes the establishment of a more favorable metabolic picture (increased insulin sensitivity and reduced lipidemia); the reasons for his withdrawal from the market are to be found in the high risk of serious psychiatric and neurological disorders, including the risk of suicide.
Topiramate
Topiramate, an antiepileptic agent that causes weight loss, authorized for the treatment of epilepsy and some forms of migraine, is often misused for slimming purposes due to its ability to suppress appetite; not surprisingly, it has been studied for the specific use in bulimia nervosa and in binge eating disorder. Also for topiramate there is the risk of psychological side effects, such as affective disorders, psychotic disorders and aggressive behavior.
Anorectic Supplements
Due to the serious side effects associated with anorectic drugs and the withdrawal from the market of most of the medicinal products used in the past, today there is a widespread tendency to search for possible alternatives in the world of supplements .
In fact, there are many natural substances capable of tracing the action of synthetic anorectic drugs, albeit with a milder action than common doses of use. This is the case, for example, of caffeine (mate, cola, guarana, coffee, long-infused tea, cocoa), sinephrine (bitter orange, rind) and ephedrine (Ephedra, aerial parts, not allowed as a supplement), which act as antifame, mimicking the action of amphetamine derivatives both in terms of appetite suppression and the stimulating effect on body metabolism.
Regarding serotonergic anorectic supplements, we report 5-hydroxytryptophan, an amino acid derivative, capable of crossing the blood-brain barrier and increasing the synthesis of serotonin.
Finally, an anorectic effect can be ascribed to fibers (bran, guar and guar gum, xanthan, karaya gum, psyllium, psyllium seeds, agar agar, glucomannan, pectin, Konjac flour, algina and alginic acid, carrageenan), which, if taken before meals together with plenty of water, they swell in the stomach by stretching the gastric walls, increasing the sense of satiety and reducing the intake of food.
