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Cyproheptadine (cyproheptadine hydrochloride) is a serotonin and histamine antagonist with anticholinergic and sedative effects. Antiserotonin and antihistamine drugs appear to compete with serotonin and histamine, respectively, for receptor sites.

Pharmacokinetics and Metabolism

After a single 4 mg oral dose of ¹⁴C-labelled cyproheptadine (cyproheptadine hydrochloride) HCl in normal subjects, given as tablets 2% to 20% of the radioactivity was excreted in the stools. Only about 34% of the stool radioactivity was unchanged drug, corresponding to less than 5.7% of the dose. At least 40% of the administered radioactivity was excreted in the urine. No detectable amounts of unchanged drug were present in the urine of patients on chronic 12-20 mg daily doses. The principal metabolite found in human urine has been identified as a quaternary ammonium glucuronide conjugate of cyproheptadine (cyproheptadine hydrochloride) . Elimination is diminished in renal insufficiency.

Last reviewed on RxList: 4/3/2009
This monograph has been modified to include the generic and brand name in many instances.