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Systematic (IUPAC) name
4-(5 H-dibenzo [a,d]cyclohepten-5-ylidene)- 1 -methylpiperidine hydrochloride
CAS number 129-03-3
ATC code R06AX02
PubChem 2913
DrugBank APRD00033
Chemical data
Formula C21H21N 
Mol. mass 287.398 g/mol
Pharmacokinetic data
Bioavailability  ?
Protein binding 96 to 99%
Metabolism Hepatic and renal
Half life 1 to 4 hours
Excretion Fecal and renal
Therapeutic considerations
Pregnancy cat.


Legal status


Routes Oral only

Cyproheptadine (usually as cyproheptadine hydrochloride, trade name Periactin) is an antihistaminic and antiserotonergic agent. It acts as a 5-HT2 receptor antagonist and also blocks calcium channels.


Cyproheptadine is used in the treatment of allergies (specifically Hay fever) and is also used to stimulate appetite in underweight people (e.g. anorexia nervosa).

Cyproheptadine may also be used to combat SSRI-induced sexual dysfunction, but is used cautiously in this manner because it may reverse the effects of the SSRI.

Cyproheptadine is also used for the treatment of Cushing's Syndrome, the treatment of serotonin reactions secondary to meperidine, and may be used, though rarely, as a prophylactic drug for migraine headaches.

Useful in the treatment of Serotonin Syndrome. Antagonise the action of histamine at H1 receptors, reducing histamine-related vasodilation and increased capillary permeability.

They also have anticholinergic activity, some have alpha-blocking activity and some have antiserotonin activity, eg cyproheptadine.

Useful alternative to benzodiazepine hypnotics in the treatment of insomnia. Cyproheptadine may be superior to benzodiazepines in the treatment of insomnia because cyproheptadine enhances sleep quality and quantity whereas benzodiazepines tend to decrease sleep quality.[1]

Side effects

While not specifically used as a sedative, cyproheptadine causes sedation, likely due to its anti-histamine effects.

Digestive System: epigastric distress (dysphagia), loss of appetite, nausea, vomiting, (it is noted that these side effects are much more common in people with neuromuscular disorders)


  1. ^ Tokunaga S; Takeda Y, Shinomiya K, Hirase M, Kamei C. (Feb 2007). "Effects of some H1-antagonists on the sleep-wake cycle in sleep-disturbed rats." (pdf). J Pharmacol Sci. 103 (2): 201-6. PMID 17287588.
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Cyproheptadine". A list of authors is available in Wikipedia.
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