Orexigenic

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 drugs 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 antidepressants (TCAs), tetracyclic antidepressants, natural or synthetic cannabinoids, first-generation antihistamines, most antipsychotics and many steroid hormones.

Drugs with orexigenic effects include the following:


 * Alcohol, GHB, and other sedatives such as some benzodiazepine and nonbenzodiazepine tranquilizers and sleeping pills
 * Anti-depressants (some SSRIs, Mianserin, etc.)
 * 5-HT2C receptor antagonists/inverse agonists (e.g., mirtazapine, mianserin, olanzapine, quetiapine, risperidone, amitriptyline, imipramine, cyproheptadine, etc.)
 * H1 receptor antagonists/inverse agonists (e.g., buclizine, mirtazapine, mianserin, olanzapine, quetiapine, amitriptyline, etc.)
 * D1/D2 receptor antagonists (e.g., haloperidol, chlorpromazine, olanzapine, risperidone, etc.)
 * α1-adrenergic receptor antagonists such as doxazosin (many heterocyclic antidepressants and antipsychotics also block this site)
 * α2-adrenergic receptor agonists (e.g., clonidine, guanfacine, etc.)
 * some beta blockers such as propanolol
 * natural or synthetic CB1 receptor agonists (e.g., THC or dronabinol (found in Cannabis), nabilone, JWH-018 etc.)
 * Corticosteroids (e.g. prednisone or dexamethasone)
 * Sodium valproate (Depakote)
 * Megestrol
 * Pregabalin
 * Sulfonylurea antidiabetic drugs such as glibenclamide and chlorpropamide
 * Anabolic steroids such as boldenone, oxymetholone or methandrostenolone
 * some kappa opioid receptor agonists such as tifluadom