Orexigenic
Encyclopedia
An orexigenic is a drug or hormone that increases appetite. This can be a naturally occurring neuropeptide
hormone such as ghrelin
, orexin
or neuropeptide Y
, or a medication
which increases hunger and therefore enhances food consumption. Usually hunger enhancement is considered an undesirable side effect
of certain drug
s as it leads to unwanted weight gain
, but sometimes it can be beneficial and a drug may be prescribed solely for this purpose, especially when the patient is suffering from severe hunger loss or muscle wasting due to cystic fibrosis
, anorexia
, old age
, cancer
or AIDS
. There are several widely used drugs which can cause a boost in hunger, including tricyclic antidepressant
s (TCAs), tetracyclic antidepressant
s, natural or synthetic cannabinoids, first-generation antihistamine
s, most antipsychotic
s and many steroid hormone
s.
Drugs with orexigenic effects include the following:
Neuropeptide
Neuropeptides are small protein-like molecules used by neurons to communicate with each other. They are neuronal signaling molecules, influence the activity of the brain in specific ways and are thus involved in particular brain functions, like analgesia, reward, food intake, learning and...
hormone such as ghrelin
Ghrelin
Ghrelin is a 28 amino acid peptide and hormone that is produced mainly by P/D1 cells lining the fundus of the human stomach and epsilon cells of the pancreas that stimulates hunger. Ghrelin levels increase before meals and decrease after meals. It is considered the counterpart of the hormone...
, orexin
Orexin
Orexins, also called hypocretins, are the common names given to a pair of excitatory neuropeptide hormones that were simultaneously discovered by two groups of researchers in rat brains....
or neuropeptide Y
Neuropeptide Y
Neuropeptide Y is a 36-amino acid peptide neurotransmitter found in the brain and autonomic nervous system."NPY has been associated with a number of physiologic processes in the brain, including the regulation of energy balance, memory and learning, and epilepsy." The main effect is increased food...
, or a medication
Medication
A pharmaceutical drug, also referred to as medicine, medication or medicament, can be loosely defined as any chemical substance intended for use in the medical diagnosis, cure, treatment, or prevention of disease.- Classification :...
which increases hunger and therefore enhances food consumption. Usually hunger enhancement is considered an undesirable side effect
Side effect
In medicine, a side effect is an effect, whether therapeutic or adverse, that is secondary to the one intended; although the term is predominantly employed to describe adverse effects, it can also apply to beneficial, but unintended, consequences of the use of a drug.Occasionally, drugs are...
of certain drug
Drug
A drug, broadly speaking, is any substance that, when absorbed into the body of a living organism, alters normal bodily function. There is no single, precise definition, as there are different meanings in drug control law, government regulations, medicine, and colloquial usage.In pharmacology, a...
s as it leads to unwanted weight gain
Weight gain
Weight gain is an increase in body weight. This can be either an increase in muscle mass, fat deposits, or excess fluids such as water.-Description:...
, but sometimes it can be beneficial and a drug may be prescribed solely for this purpose, especially when the patient is suffering from severe hunger loss or muscle wasting due to cystic fibrosis
Cystic fibrosis
Cystic fibrosis is a recessive genetic disease affecting most critically the lungs, and also the pancreas, liver, and intestine...
, anorexia
Anorexia (symptom)
Anorexia is the decreased sensation of appetite...
, old age
Old age
Old age consists of ages nearing or surpassing the average life span of human beings, and thus the end of the human life cycle...
, cancer
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
or AIDS
AIDS
Acquired immune deficiency syndrome or acquired immunodeficiency syndrome is a disease of the human immune system caused by the human immunodeficiency virus...
. There are several widely used drugs which can cause a boost in hunger, including tricyclic antidepressant
Tricyclic antidepressant
Tricyclic antidepressants are heterocyclic chemical compounds used primarily as antidepressants. The TCAs were first discovered in the early 1950s and were subsequently introduced later in the decade; they are named after their chemical structure, which contains three rings of atoms...
s (TCAs), tetracyclic antidepressant
Tetracyclic antidepressant
Tetracyclic antidepressants are a class of drugs used primarily as antidepressants that were first introduced in the 1970s. They are named after their chemical structure which contains four rings of atoms and are closely related to the tricyclic antidepressants which contain three rings of...
s, natural or synthetic cannabinoids, first-generation antihistamine
Antihistamine
An H1 antagonist is a histamine antagonist of the H1 receptor that serves to reduce or eliminate effects mediated by histamine, an endogenous chemical mediator released during allergic reactions...
s, most antipsychotic
Antipsychotic
An antipsychotic is a tranquilizing psychiatric medication primarily used to manage psychosis , particularly in schizophrenia and bipolar disorder. A first generation of antipsychotics, known as typical antipsychotics, was discovered in the 1950s...
s and many steroid hormone
Steroid hormone
A steroid hormone is a steroid that acts as a hormone. Steroid hormones can be grouped into five groups by the receptors to which they bind: glucocorticoids, mineralocorticoids, androgens, estrogens, and progestogens...
s.
Drugs with orexigenic effects include the following:
- AlcoholAlcoholic beverageAn alcoholic beverage is a drink containing ethanol, commonly known as alcohol. Alcoholic beverages are divided into three general classes: beers, wines, and spirits. They are legally consumed in most countries, and over 100 countries have laws regulating their production, sale, and consumption...
, GHBGamma-Hydroxybutyric acidγ-Hydroxybutyric acid , also known as 4-hydroxybutanoic acid and sodium oxybate when used for medicinal purposes, is a naturally occurring substance found in the central nervous system, wine, beef, small citrus fruits, and almost all animals in small amounts. It is also categorized as an illegal...
, and other sedatives such as some benzodiazepineBenzodiazepineA benzodiazepine is a psychoactive drug whose core chemical structure is the fusion of a benzene ring and a diazepine ring...
and nonbenzodiazepineNonbenzodiazepineThe nonbenzodiazepines, also called benzodiazepine-like drugs, are a class of psychoactive drugs pharmacologically resembling the benzodiazepines, with similar benefits, side effects and risks, despite having dissimilar or entirely different chemical structures.-Classes:There are currently three...
tranquilizers and sleeping pills - Anti-depressants (some SSRIs, MianserinMianserinMianserin is a psychoactive drug of the tetracyclic antidepressant chemical class which is classified as a noradrenergic and specific serotonergic antidepressant and has antidepressant, anxiolytic, hypnotic, antiemetic, orexigenic, and antihistamine effects...
, etc.) - 5-HT2C receptor5-HT2C receptorThe 5-HT2C receptor is a subtype of 5-HT receptor that binds the endogenous neurotransmitter serotonin . It is a G protein-coupled receptor that is coupled to Gq/G11 and mediates excitatory neurotransmission. HTR2C denotes the human gene encoding for the receptor, that in humans is located at the...
antagonistReceptor antagonistA receptor antagonist is a type of receptor ligand or drug that does not provoke a biological response itself upon binding to a receptor, but blocks or dampens agonist-mediated responses...
s/inverse agonistInverse agonistIn the field of pharmacology, an inverse agonist is an agent that binds to the same receptor as an agonist but induces a pharmacological response opposite to that agonist....
s (e.g., mirtazapineMirtazapineMirtazapine is a tetracyclic antidepressant used primarily in the treatment of depression. It is also sometimes used as a hypnotic, antiemetic, and appetite stimulant, and for the treatment of anxiety, among other indications...
, mianserinMianserinMianserin is a psychoactive drug of the tetracyclic antidepressant chemical class which is classified as a noradrenergic and specific serotonergic antidepressant and has antidepressant, anxiolytic, hypnotic, antiemetic, orexigenic, and antihistamine effects...
, olanzapineOlanzapineOlanzapine is an atypical antipsychotic, approved by the FDA for the treatment of schizophrenia and bipolar disorder...
, quetiapineQuetiapineQuetiapine , is an atypical antipsychotic approved for the treatment of schizophrenia, and bipolar disorder....
, risperidoneRisperidoneRisperidone is a second generation or atypical antipsychotic, sold under the trade name . It is used to treat schizophrenia , schizoaffective disorder, the mixed and manic states associated with bipolar disorder, and irritability in people with autism...
, amitriptylineAmitriptylineAmitriptyline is a tricyclic antidepressant . It is the most widely used TCA and has at least equal efficacy against depression as the newer class of SSRIs...
, imipramineImipramineImipramine , also known as melipramine, is an antidepressant medication, a tricyclic antidepressant of the dibenzazepine group...
, cyproheptadineCyproheptadineCyproheptadine , sold under the brand name Periactin, is a first-generation antihistamine with additional anticholinergic, antiserotonergic, and local anesthetic properties.- Indications :...
, etc.) - H1 receptor antagonistReceptor antagonistA receptor antagonist is a type of receptor ligand or drug that does not provoke a biological response itself upon binding to a receptor, but blocks or dampens agonist-mediated responses...
s/inverse agonistInverse agonistIn the field of pharmacology, an inverse agonist is an agent that binds to the same receptor as an agonist but induces a pharmacological response opposite to that agonist....
s (e.g., buclizineBuclizineBuclizine is an antihistamine and anticholinergic of the piperazine derivative family. It is considered to be an antiemetic, similar to meclozine....
, mirtazapineMirtazapineMirtazapine is a tetracyclic antidepressant used primarily in the treatment of depression. It is also sometimes used as a hypnotic, antiemetic, and appetite stimulant, and for the treatment of anxiety, among other indications...
, mianserinMianserinMianserin is a psychoactive drug of the tetracyclic antidepressant chemical class which is classified as a noradrenergic and specific serotonergic antidepressant and has antidepressant, anxiolytic, hypnotic, antiemetic, orexigenic, and antihistamine effects...
, olanzapineOlanzapineOlanzapine is an atypical antipsychotic, approved by the FDA for the treatment of schizophrenia and bipolar disorder...
, quetiapineQuetiapineQuetiapine , is an atypical antipsychotic approved for the treatment of schizophrenia, and bipolar disorder....
, amitriptylineAmitriptylineAmitriptyline is a tricyclic antidepressant . It is the most widely used TCA and has at least equal efficacy against depression as the newer class of SSRIs...
, etc.) - D1/D2 receptor antagonists (e.g., haloperidolHaloperidolHaloperidol is a typical antipsychotic. It is in the butyrophenone class of antipsychotic medications and has pharmacological effects similar to the phenothiazines....
, chlorpromazineChlorpromazineChlorpromazine is a typical antipsychotic...
, olanzapineOlanzapineOlanzapine is an atypical antipsychotic, approved by the FDA for the treatment of schizophrenia and bipolar disorder...
, risperidoneRisperidoneRisperidone is a second generation or atypical antipsychotic, sold under the trade name . It is used to treat schizophrenia , schizoaffective disorder, the mixed and manic states associated with bipolar disorder, and irritability in people with autism...
, etc.) - α1-adrenergic receptor antagonists such as doxazosinDoxazosinDoxazosin mesylate, a quinazoline compound sold by Pfizer under the brand names Cardura and Carduran, is an α1a-selective alpha blocker used to treat high blood pressure and urinary retention associated with benign prostatic hyperplasia ....
(many heterocyclic antidepressantAntidepressantAn antidepressant is a psychiatric medication used to alleviate mood disorders, such as major depression and dysthymia and anxiety disorders such as social anxiety disorder. According to Gelder, Mayou &*Geddes people with a depressive illness will experience a therapeutic effect to their mood;...
s and antipsychoticAntipsychoticAn antipsychotic is a tranquilizing psychiatric medication primarily used to manage psychosis , particularly in schizophrenia and bipolar disorder. A first generation of antipsychotics, known as typical antipsychotics, was discovered in the 1950s...
s also block this site) - α2-adrenergic receptor agonistAgonistAn agonist is a chemical that binds to a receptor of a cell and triggers a response by that cell. Agonists often mimic the action of a naturally occurring substance...
s (e.g., clonidineClonidineClonidine is a sympatholytic medication used to treat medical conditions, such as high blood pressure, some pain conditions, ADHD and anxiety/panic disorder...
, guanfacineGuanfacineGuanfacine is a sympatholytic. It is an agonist of the α2A subtype of norepinephrine receptors. These receptors are concentrated heavily in the prefrontal cortex and the locus coeruleus, with the potential to improve attention abilities via modulating post-synaptic α2A receptors in the prefrontal...
, etc.) - some beta blockerBeta blockerBeta blockers or beta-adrenergic blocking agents, beta-adrenergic antagonists, beta-adrenoreceptor antagonists or beta antagonists, are a class of drugs used for various indications. They are particularly for the management of cardiac arrhythmias, cardioprotection after myocardial infarction ,...
s such as propanolol - natural or synthetic CB1 receptor agonistAgonistAn agonist is a chemical that binds to a receptor of a cell and triggers a response by that cell. Agonists often mimic the action of a naturally occurring substance...
s (e.g., THCTetrahydrocannabinolTetrahydrocannabinol , also known as delta-9-tetrahydrocannabinol , Δ1-THC , or dronabinol, is the main chemical psychoactive substance found in the cannabis plant. It was first isolated in 1964. In pure form, it is a glassy solid when cold, and becomes viscous and sticky if warmed...
or dronabinol (found in CannabisCannabisCannabis is a genus of flowering plants that includes three putative species, Cannabis sativa, Cannabis indica, and Cannabis ruderalis. These three taxa are indigenous to Central Asia, and South Asia. Cannabis has long been used for fibre , for seed and seed oils, for medicinal purposes, and as a...
), nabiloneNabiloneNabilone is a synthetic cannabinoid with therapeutic use as an antiemetic and as an adjunct analgesic for neuropathic pain. It is a synthetic cannabinoid, which mimics the main ingredient of cannabis...
, JWH-018JWH-018JWH-018 or AM-678 is an analgesic chemical from the naphthoylindole family, which acts as a full agonist at both the CB1 and CB2 cannabinoid receptors, with some selectivity for CB2...
etc.) - CorticosteroidCorticosteroidCorticosteroids are a class of steroid hormones that are produced in the adrenal cortex. Corticosteroids are involved in a wide range of physiologic systems such as stress response, immune response and regulation of inflammation, carbohydrate metabolism, protein catabolism, blood electrolyte...
s (e.g. prednisonePrednisonePrednisone is a synthetic corticosteroid drug that is particularly effective as an immunosuppressant drug. It is used to treat certain inflammatory diseases and some types of cancer, but has significant adverse effects...
or dexamethasoneDexamethasoneDexamethasone is a potent synthetic member of the glucocorticoid class of steroid drugs. It acts as an anti-inflammatory and immunosuppressant...
) - Sodium valproateSodium valproateSodium valproate or valproate sodium is the sodium salt of valproic acid and is an anticonvulsant used in the treatment of epilepsy, anorexia nervosa, panic attack, anxiety disorder, posttraumatic stress disorder, migraine and bipolar disorder, as well as other psychiatric conditions requiring...
(Depakote) - MegestrolMegestrolMegestrol is a progesterone derivative with antineoplastic properties used in the treatment of advanced carcinoma of the breast and endometrium. When given in relatively high doses, Megestrol can substantially increase appetite in most individuals, even those with advanced cancer...
- PregabalinPregabalinPregabalin is an anticonvulsant drug used for neuropathic pain and as an adjunct therapy for partial seizures with or without secondary generalization in adults. It has also been found effective for generalized anxiety disorder and is approved for this use in the European Union. It was designed...
- SulfonylureaSulfonylureaSulfonylurea derivatives are a class of antidiabetic drugs that are used in the management of diabetes mellitus type 2. They act by increasing insulin release from the beta cells in the pancreas.-First generation:* Carbutamide...
antidiabetic drugs such as glibenclamideGlibenclamideGlibenclamide , also known as glyburide , is an antidiabetic drug in a class of medications known as sulfonylureas, closely related to sulfa drugs...
and chlorpropamideChlorpropamideChlorpropamide is a drug in the sulphonylurea class used to treat type 2 diabetes mellitus. It is a long-acting sulphonylurea. It has more side effects than other sulphonylureas and its use is no longer recommended.-Mechanism of action:... - Anabolic steroidAnabolic steroidAnabolic steroids, technically known as anabolic-androgen steroids or colloquially simply as "steroids", are drugs that mimic the effects of testosterone and dihydrotestosterone in the body. They increase protein synthesis within cells, which results in the buildup of cellular tissue ,...
s such as boldenoneBoldenoneBoldenone , also known under the trade names Equipoise, Ganabol, Equigan and Ultragan, is an anabolic steroid developed for veterinary use, mostly for treatment of horses...
, oxymetholoneOxymetholoneOxymetholone is a synthetic anabolic steroid developed in 1960 by Zoltan 'Anadrol Z' F. Its primary clinical applications include treatment of osteoporosis and anaemia, as well as stimulating muscle growth in undernourished or underdeveloped patients. The drug was approved for human use by the FDA...
or methandrostenoloneMethandrostenoloneMethandrostenolone is an orally-effective anabolic steroid originally developed by John Ziegler and released in the US in the early 1960s by Ciba. It was used as an aid to muscle growth by bodybuilders until its ban by Congress under the Controlled Substances Act... - some kappa opioid receptorKappa Opioid receptorThe κ-opioid receptor is a protein that in humans is encoded by the OPRK1 gene. The κ-opioid receptor is one of five related receptors that bind opium-like compounds in the brain and are responsible for mediating the effects of these compounds...
agonists such as tifluadomTifluadomTifluadom is a benzodiazepine derivative with an unusual activity profile. Unlike most benzodiazepines, tifluadom has no activity as a GABAA agonist, but instead is a selective agonist for the κ-opioid receptor...
See also
- AnorecticAnorecticAn anorectic or anorexic , also known as anorexigenic or appetite suppressant, is a dietary supplement and/or drug which reduces appetite, food consumption, and as a result, causes weight loss to occur.-List of anorectics:Numerous pharmaceutical compounds are marketed as appetite suppressants.The...
- AnorexiaAnorexia (symptom)Anorexia is the decreased sensation of appetite...
- Eating disorderEating disorderEating disorders refer to a group of conditions defined by abnormal eating habits that may involve either insufficient or excessive food intake to the detriment of an individual's physical and mental health. Bulimia nervosa, anorexia nervosa, and binge eating disorder are the most common specific...
- ObesityObesityObesity is a medical condition in which excess body fat has accumulated to the extent that it may have an adverse effect on health, leading to reduced life expectancy and/or increased health problems...
- Organic feeding disorder
- PolydipsiaPolydipsiaPolydipsia is a medical symptom in which the patient displays excessive thirst. The word derives from the Greek πολυδιψία, which is derived from πολύς + δίψα...
- PolyphagiaPolyphagiaPolyphagia means "eating too much". It derives from the Greek words πολύς which means "very much", and φαγῶ , verb for "I eat"....
(or hyperphagia)