cyproheptadine + dexamethasone (Merck & Co.)

The combination of **cyproheptadine** and **dexamethasone** is a pharmacological regimen consisting of a first-generation antihistamine and a potent synthetic glucocorticoid. Cyproheptadine acts as a competitive antagonist at histamine H1 receptors and serotonin 5-HT2 receptors; while primarily indicated for allergic conditions such as urticaria and rhinitis, its antiserotonergic activity in the hypothalamus often leads to its off-label use as an appetite stimulant. Dexamethasone is a long-acting corticosteroid that binds to the glucocorticoid receptor to exert powerful anti-inflammatory and immunosuppressive effects by modulating gene transcription. In specific regions, particularly in Southeast Asia, this combination is frequently co-administered or sold as a set (often involving the brand **Dayhist** for the cyproheptadine component) for the management of severe allergies or, more controversially, to promote rapid weight gain. The use of this combination for weight gain is associated with significant clinical risks, including the development of iatrogenic Cushing's syndrome, adrenal insufficiency, and metabolic disturbances.

Brand names

DecadronPeriactinDextrol

Other names

Cyproheptadine and DexamethasoneDayhist and Dexamethasone