Orexigenic

An orexigenic, or appetite stimulant, is a drug, hormone, or compound that increases appetite. This can be a naturally occurring neuropeptide hormone such as ghrelin, orexin or neuropeptide Y,^[1][2] or a medication which increases hunger and therefore enhances food consumption. Usually appetite enhancement is considered an undesirable side effect of certain drugs as it leads to unwanted weight gain,^[3][4][5] but sometimes it can be beneficial and a drug may be prescribed solely for this purpose, especially when the patient is suffering from severe appetite loss or muscle wasting due to cystic fibrosis, anorexia, old age, cancer or AIDS.^{[6][7][8][9][10]} There are several widely used drugs which can cause a boost in appetite, including tricyclic antidepressants (TCAs), tetracyclic antidepressants, natural or synthetic cannabinoids, first-generation antihistamines, most antipsychotics and many steroid hormones.

Agents with orexigenic effects include the following:

• 5-HT_2C receptor antagonists/inverse agonists — mirtazapine, olanzapine, quetiapine, amitriptyline, cyproheptadine, lurasidone
• H₁ receptor antagonists/inverse agonists — mirtazapine, olanzapine, quetiapine, amitriptyline, cyproheptadine
• Dopamine antagonists — haloperidol, chlorpromazine, olanzapine, risperidone, quetiapine
• Adrenergic antagonists:
  • β blockers — propranolol, etc.
  • α₂ adrenergic antagonists — mirtazapine, mianserin
  • Mixed α₁/β blockers — carvedilol
• Adrenergic agonists — clonidine
• CB₁ receptor agonists (cannabinoids — THC/dronabinol (a component of Cannabis), nabilone
• Corticosteroids — dexamethasone, prednisone, hydrocortisone
• Certain pregnene steroids — megestrol acetate, medroxyprogesterone acetate
• Anabolic steroids — oxandrolone, nandrolone, testosterone
• Sulfonylurea antidiabetic drugs such as glibenclamide, chlorpropamide and tolbutamide
• Mood stabilizers such as lithium
• Some anti-epileptic drugs such as valproate, carbamazepine and gabapentin^[11]
• α₂δ VDCC ligands — gabapentin, pregabalin^[12]
• Ghrelin receptor agonists such as anamorelin, GHRP-6, ibutamoren, ipamorelin, and pralmorelin
• MC₄ receptor antagonists
• Insulin
• Sugars such as fructose^[13]

See also

• Anorectic
• Anorexia
• Eating disorder
• Obesity
• Obesogen
• Organic feeding disorder
• Polydipsia
• Polyphagia (or hyperphagia)

References

1. Diepvens K, Häberer D, Westerterp-Plantenga M (Mar 2008). "Different proteins and biopeptides differently affect satiety and anorexigenic/orexigenic hormones in healthy humans". Int J Obes (Lond). 32 (3): 510–8. doi:10.1038/sj.ijo.0803758. PMID 18345020.
2. Akimoto S, Miyasaka K (July 2010). "Age-associated changes of hunger-regulating peptides". Geriatrics & Gerontology International. 10 Suppl 1: S107–19. doi:10.1111/j.1447-0594.2010.00587.x. PMID 20590826.
3. Purnell JQ, Weyer C (2003). "Weight effect of current and experimental drugs for diabetes mellitus: from promotion to alleviation of obesity". Treatments in Endocrinology 2 (1): 33–47. doi:10.2165/00024677-200302010-00004. PMID 15871553.
4. Hermansen K, Mortensen LS (2007). "Bodyweight changes associated with antihyperglycaemic agents in type 2 diabetes mellitus". Drug Safety : an International Journal of Medical Toxicology and Drug Experience 30 (12): 1127–42. doi:10.2165/00002018-200730120-00005. PMID 18035865.
5. Maayan L, Correll CU (July 2010). "Management of antipsychotic-related weight gain". Expert Review of Neurotherapeutics 10 (7): 1175–200. doi:10.1586/ern.10.85. PMC 3501406. PMID 20586697.
6. Strasser F, Bruera ED (June 2002). "Update on anorexia and cachexia". Hematology/oncology Clinics of North America 16 (3): 589–617. doi:10.1016/s0889-8588(02)00011-4. PMID 12170570.
7. Nasr SZ, Drury D (March 2008). "use in cystic fibrosis". Pediatric Pulmonology 43 (3): 209–19. doi:10.1002/ppul.20766. PMID 18219690.
8. Morley JE (2007). "Weight loss in older persons: new therapeutic approaches". Current Pharmaceutical Design 13 (35): 3637–47. doi:10.2174/138161207782794149. PMID 18220800.
9. Fox CB, Treadway AK, Blaszczyk AT, Sleeper RB (April 2009). "Megestrol acetate and mirtazapine for the treatment of unplanned weight loss in the elderly". Pharmacotherapy 29 (4): 383–97. doi:10.1592/phco.29.4.383. PMID 19323618.
10. Holmes S (July 2009). "A difficult clinical problem: diagnosis, impact and clinical management of cachexia in palliative care". International Journal of Palliative Nursing 15 (7): 320, 322–6. PMID 19648846.
11. Ness-Abramof R, Apovian CM (Aug 2005). "Drug-induced weight gain". Drugs Today (Barcelona) 41 (8): 547–55. doi:10.1358/dot.2005.41.8.893630. PMID 16234878.
12. LYRICA^® (pregabalin), CV. Full Prescribing Information, Section 5.7 (Weight Gain). Pfizer, Inc. Revised June, 2013.
13. http://themedicalbiochemistrypage.org/fructose.php