Cyproheptadine HCl is available in tablets, containing 4 mg of cyproheptadine hydrochloride, and as a syrup in which 5 ml contains 2 mg of cyproheptadine hydrochloride, with a pH range of 3.5 to 4.5. Antiserotonin and antihistamine drugs appear to compete with serotonin and histamine, respectively, for receptor sites. No significant difference in the mean urinary excretion exists between the tablet and syrup formulations. No detectable amounts of unchanged drug were present in the urine of patients on chronic 12-20 mg daily doses of cyproheptadine HCl Syrup. The principle metabolite found in human urine has been identified as a quaternary ammonium glucuronide conjugate of cyproheptadine.
Elimination is diminished in renal insufficiency.
Dermatographism As therapy for anaphylactic reactions adjunctive to epinephrine and other standard measures after the acute manifestations have been controlled. This drug should not be used in newborn or premature infants. Because of the higher risk of antihistamines for infants generally and for newborns and prematures in particular, antihistamine therapy is contraindicated in nursing mothers. Of antihistamines, particularly in infants and children, may produce hallucinations, central nervous system depression, convulsions, and death. CNS Depressants Antihistamines may have additive effects with alcohol and other CNS depressants, e.g., hypnotics, sedatives, tranquilizers, antianxiety agents.