Antiobesity agents/Anorectics (A08)
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An anorectic or anorexic is a drug which reduces appetite, resulting in lower food consumption, leading to weight loss.[1] These substances work by affecting the central nervous system or certain neurotransmitters to create a feeling of fullness or reduce the desire to eat. The understanding of anorexiant effects is crucial in the development of interventions for weight management, eating disorders, and related health concerns. The anorexiant effect can be induced through diverse mechanisms, ranging from hormonal regulation to neural signaling. Ghrelin, leptin, and peptide YY are among the hormones involved in appetite control. Additionally, neurotransmitters such as serotonin and dopamine in the central nervous system contribute significantly to the regulation of food intake.
By contrast, an appetite stimulant is referred to as orexigenic.
The term is (from the Greek ἀν- (an-) = "without" and ὄρεξις (órexis) = "appetite"), and such drugs are also known as anorexigenic, anorexiant, or appetite suppressant.
Used on a short-term basis clinically to treat obesity, some appetite suppressants are also available over-the-counter. Several appetite suppressants are based on a mix of natural ingredients, mostly using green tea as its basis, in combination with other plant extracts such as fucoxanthin, found naturally in seaweed. Drugs of this class are frequently stimulants of the phenethylamine family, related to amphetamine.[citation needed]
The German and Finnish[2] militaries issued amphetamines (Pervitin) to soldiers commonly during the Second World War.[3] Similarly, the UK military was supplied with more than 72 million Benzedrine tablets and the US military with an approximately equal amount for situations, in which fatigue was not deemed to be an acceptable option.[4] Following the war, large amphetamine surpluses were redirected for use on the black[5] and the civilian market. Indeed, amphetamine itself was sold commercially as an appetite suppressant until it was outlawed in most parts of the world in the late 1950s because of safety issues. Many amphetamines produce side effects, including addiction, tachycardia and hypertension,[6] making prolonged unsupervised use dangerous.
Epidemics of fatal pulmonary hypertension and heart valve damage associated with pharmaceutical anorectic agents have led to the withdrawal of products from the market. This was the case with aminorex in the 1960s, and again in the 1990s with fenfluramine (see: Fen-phen).[7] Likewise, association of the related appetite suppressant phenylpropanolamine with hemorrhagic stroke led the Food and Drug Administration (FDA) to request its withdrawal from the market in the United States in 2000, and similar concerns regarding ephedrine resulted in an FDA ban on its inclusion in dietary supplements in 2004. A Federal judge later overturned this ban in 2005 during a challenge by supplement maker Nutraceuticals. It is also debatable as to whether the ephedrine ban had more to do with its use as a precursor in methamphetamine manufacture rather than health concerns with the ingredient as such.[citation needed]
Weight loss effects of water have been subject to some scientific research as a potential non-pharmacological approach.[8] Drinking water prior to each meal may help in appetite suppression. Consumption of 500 mL (approximately 17 fl oz) of water 30 minutes before meals has been correlated with modest weight loss (1–2 kg; 2 to 4 lb) in obese men and women over a period of 8 to 12 weeks.[9][10]
Numerous pharmaceutical compounds are marketed as appetite suppressants.
The following drugs are listed as "centrally-acting antiobesity preparations" in the Anatomical Therapeutic Chemical Classification System:[11]
The following are listed as appetite depressants by MeSH, an index of medical journal articles and books.[13]
Other compounds with known appetite suppressant activity include: