Ananorectic is a drug that reducesappetite, resulting in lower food consumption, leading toweight loss.^[1] These substances work by affecting thecentral nervous system or certainneurotransmitters to create a feeling of fullness or reduce the desire to eat. The understanding of anorexiant effects is crucial in the development of interventions forweight 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, andpeptide YY are among the hormones involved in appetite control. Additionally, neurotransmitters such asserotonin anddopamine in the central nervous system contribute significantly to the regulation of food intake.

By contrast, an appetite stimulant is referred to asorexigenic.

The term is (from theGreekἀν-an-'without' andὄρεξιςórexis'appetite'), and such drugs are also known asanorexigenic,anorexiant, orappetite suppressant.

Used on a short-term basis clinically to treatobesity, some appetite suppressants are also availableover-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 asfucoxanthin, found naturally in seaweed.Drugs of this class are frequentlystimulants of thephenethylamine family, related toamphetamine.^[2]

The German and Finnish^[3] militaries issued amphetamines (Pervitin) to soldiers commonly during theSecond World War.^[4] Similarly, theUK military was supplied with more than 72 millionBenzedrine tablets and theUS military with an approximately equal amount for situations, in which fatigue was not deemed to be an acceptable option.^[5] Following the war, large amphetamine surpluses were redirected for use on the black^[6] 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, includingaddiction,tachycardia andhypertension,^[7] making prolonged unsupervised use dangerous.

Epidemics of fatalpulmonary hypertension andheart valve damage associated with pharmaceutical anorectic agents have led to the withdrawal of products from the market. This was the case withaminorex in the 1960s, and again in the 1990s withfenfluramine (see:Fen-phen).^[8] Likewise, association of the related appetite suppressantphenylpropanolamine withhemorrhagic stroke led theFood and Drug Administration (FDA) to request its withdrawal from the market in the United States in 2000, and similar concerns regardingephedrine 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 aprecursor inmethamphetamine 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 potentialnon-pharmacological approach.^[9] Drinking water prior to each meal may help in appetite suppression. Consumption of 500 mL (18 imp fl oz; 17 US fl oz) of water 30 minutes before meals has been correlated with modest weight loss (1–2 kg; 2.2–4.4 lb) in obese men and women over a period of 8 to 12 weeks.^[10][11]

Refeeding syndrome (RFS) is ametabolic disturbance which occurs as a result of reinstitution of nutrition in people and animals who arestarved, severelymalnourished, or metabolically stressed because of severe illness. When too much food or liquid nutrition supplement is eaten during the initial four to seven days following amalnutrition event, the production ofglycogen,fat andprotein in cells may cause lowserum concentrations ofpotassium,magnesium andphosphate.^[12][13] Theelectrolyte imbalance may cause neurologic, pulmonary, cardiac, neuromuscular, and hematologic symptoms—many of which, if severe enough, may result in death.

Refeeding syndrome can occur when someone who has not eaten for a long time, starts eating normal or even binging amounts of food.^[14]

Individuals withdrug abuse who begin to reintroduce normal eating habits after a period of malnutrition may be at increased risk for refeeding syndrome.^[15]

Numerous pharmaceutical compounds are marketed as appetite suppressants.

The following drugs are listed as "centrally-acting antiobesity preparations" in theAnatomical Therapeutic Chemical Classification System:^[16]

• Amfepramone (also known as diethylpropion)
• Bupropion andnaltrexone (combination)
• Cathine
• Clobenzorex
• Dexfenfluramine^† (theD-enantiomer of fenfluramine; withdrawn for the same reason as its racemate)
• Ephedrine (combinations)
• Etilamfetamine
• Fenfluramine^† (one of the two components [the other being phentermine] of Fen-phen. Since discontinued to its potential for causing valvulopathies andpulmonary hypertension)
• Lorcaserin (withdrawn in the United States by the FDA due to an increased risk of cancer)^[17]
• Mazindol
• Mefenorex
• Phentermine
• Sibutramine^† (in some countries withdrawn from the market because of concerns regarding its cardiovascular effects)
• Topiramate

The following are listed as appetite depressants byMeSH, an index of medical journal articles and books.^[18]

• Benfluorex (removed from the market by the EMA due to increased risk of heart disease)^[19]
• Butenolide
• Diethylpropion
• FG-7142
• Phenmetrazine^† (withdrawn in some countries due to the danger of addiction)
• Phentermine
• Phenylpropanolamine
• Pyroglutamyl-histidyl-glycine
• Sibutramine

Other compounds with known appetite suppressant activity include:

• Amphetamine-Dextroamphetamine is known to hamper appetite. Amphetamine-Dextroamphetamine is used to treatAttention deficit hyperactivity disorder (ADHD) and is usually under the trade name "Adderall" or "Mydayis".^[20][21]
• Amphetamine sulfate (also known as amfetamine) –US FDA-approved for the treatment ofexogenous obesity under the brand name "Evekeo".^[22]
• Methylphenidate
• Cocaine^[23]
• Caffeine^[24]
• Glucomannan^[25][26]
• Leptin^[27]
• Lisdexamphetamine - US FDA approved for the treatment of binge-eating disorder in adults under the brand name "Vyvanse".^[28]
• Methamphetamine hydrochloride – USFDA-approved for the treatment of obesity (as a short-term) under the brand name "Desoxyn".^[29]
• Nicotine^[30]
• Liraglutide as brand name Saxenda
• Semaglutide (brand name Ozempic/Wegovy)GLP-1 agonist
• Tirzepatide (Brand Name Mounjaro, Zepbound)
• Metformin
• Opiates/opioids such as heroin,morphine,codeine,oxycodone,fentanyl, etc.

• Anti-obesity medication

• Anorectics at the U.S. National Library of MedicineMedical Subject Headings (MeSH)
• Mitchell, Kari (January 1997)."Anorexiant Agents: Considerations for Use"(PDF).Drug Therapy Topics.University of Washington Medical Center. Archived fromthe original(PDF) on 2013-12-26. Retrieved25 December 2013.

• Anorectics

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