Periactin - General Information
A serotonin antagonist and a histamine H1 blocker used as antipruritic, appetite stimulant, antiallergic, and for the post-gastrectomy dumping syndrome, etc. [PubChem]
Pharmacology of Periactin
Periactin is a piperidine antihistamine. Unlike other antihistamines, this drug also antagonizes serotonin receptors. This action makes Periactin useful in conditions such as vascular headache and anorexia. Periactin does not prevent the release of histamine but rather competes with free histamine for binding at HA-receptor sites. Periactin competitively antagonizes the effects of histamine on HA-receptors in the GI tract, uterus, large blood vessels, and bronchial smooth muscle. Most antihistamines possess significant anticholinergic properties, but Periactin exerts only weak anticholinergic actions. Blockade of central muscarinic receptors appears to account for Periactin's antiemetic effects, although the exact mechanism is unknown. Periactin also competes with serotonin at receptor sites in smooth muscle in the intestines and other locations. Antagonism of serotonin on the appetite center of the hypothalamus may account for Periactin's ability to stimulate appetite. Periactin also has been used to counter vascular headaches, which many believe are caused by changes in serotonin activity, however it is unclear how Periactin exerts a beneficial effect on this condition.
Periactin for patients
Antihistamines may diminish mental alertness; conversely, particularly, in the young child, they may occasionally produce excitation. Patients should be warned about engaging in activities requiring mental alertness and motor coordination, such as driving a car or operating machinery.
MAO inhibitors prolong and intensify the anticholinergic effects of antihistamines. Antihistamines may have additive effects with alcohol and other CNS depressants, e.g., hypnotics, sedatives, tranquilizers, antianxiety agents.
Newborn or Premature Infants
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.
Hypersensitivity to cyproheptadine and other drugs of similar chemical structure. Monoamine oxidase inhibitor therapy
- Angle-closure glaucoma
- Stenosing peptic ulcer
- Symptomatic prostatic hypertrophy
- Bladder neck obstruction
- Pyloroduodenal obstruction
- Elderly, debilitated patients
Additional information about Periactin
Periactin Indication: For treatment of perennial and seasonal allergic rhinitis, vasomotor rhinitis, allergic conjunctivitis due to inhalant allergens and foods, mild uncomplicated allergic skin manifestations of urticaria and angioedema, amelioration of allergic reactions to blood or plasma, cold urticaria, dermatographism, and as therapy for anaphylactic reactions adjunctive to epinephrine.
Mechanism Of Action: Periactin competes with free histamine for binding at HA-receptor sites. This antagonizes the effects of histamine on HA-receptors, leading to a reduction of the negative symptoms brought on by histamine HA-receptor binding.
Drug Interactions: Donepezil Possible antagonism of action
Fluoxetine Possible antagonism of action
Galantamine Possible antagonism of action
Metyrapone This combination renders test invalid
Rivastigmine Possible antagonism of action
Food Interactions: Take with food.
Generic Name: Cyproheptadine
Synonyms: Not Available
Drug Category: Anti-Allergic Agents; Gastrointestinal Agents; Antipruritics; Antihistamine derivatives
Drug Type: Small Molecule; Approved
Absorption: Well absorbed after oral administration.
Toxicity (Overdose): Not Available
Protein Binding: 96 to 99%
Biotransformation: Hepatic (cytochrome P-450 system) and some renal.
Half Life: Not Available
Dosage Forms of Periactin: Tablet Oral
Chemical IUPAC Name: Not Available
Chemical Formula: C21H21N
Cyproheptadine on Wikipedia: https://en.wikipedia.org/wiki/Cyproheptadine
Organisms Affected: Humans and other mammals