Adult: Prophylaxis and treatment: Initially, 4 mg, may be repeated after 30 minutes if necessary. Patient who responds usually achieve relief with 8 mg, and this dosage must not be exceeded within a 4- to 6-hour period. Maintenance: 4 mg 4-6 hourly.
Oral Allergic conditions, Pruritus
Adult: Dosage must be individualised based on patient response and tolerance. Initially, 4 mg tid, adjusted as necessary. Usual therapeutic range: 4-20 mg daily in divided doses; most patients require 12-16 mg daily. Max: 0.5 mg/kg daily or 32 mg daily. Child: 2-6 years Initially, 2 mg bid or tid. Max: 12 mg daily; 7-14 years Initially, 4 mg bid or tid. Max: 16 mg daily. All doses may be adjusted as necessary according to patient weight and response. Alternatively, total daily dosage may be calculated based on body weight or BSA: ≥2 years Approx 0.25 mg/kg daily or 8 mg/m2 daily in 2-3 divided doses.
Administration
May be taken with or without food. May be taken w/ meals to reduce GI discomfort.
Contraindications
Angle-closure glaucoma, stenosing peptic ulcer, pyloroduodenal obstruction, symptomatic prostatic hypertrophy, bladder neck obstruction or predisposition to urinary retention. Patient undergoing treatment for acute asthmatic attack. Newborn or premature infants; elderly and debilitated patients. Lactation. Concomitant use with MAOIs.
Special Precautions
Patient with CV disease, including hypertension and ischaemic heart disease; thyroid dysfunction (e.g. hyperthyroidism), history of bronchial asthma, other chronic breathing disorders; increased intraocular pressure, acute porphyria. Hepatic impairment. Children (≥2 years). Pregnancy.
Adverse Reactions
Significant: CNS depression (e.g. dizziness, sedation), hypotension; excitation (in children). Blood and lymphatic system disorders: Rarely, blood dyscrasias in prolonged use (e.g. leucopenia, haemolytic anaemia, agranulocytosis, thrombocytopenia). Cardiac disorders: Palpitation, extrasystoles, tachycardia. Ear and labyrinth disorders: Tinnitus, vertigo, acute labyrinthitis. Eye disorders: Blurred vision, diplopia. Gastrointestinal disorders: Dry mouth, nausea, vomiting, diarrhoea, constipation, epigastric distress. General disorders and administration site conditions: Fatigue, rigors. Hepatobiliary disorders: Jaundice, hepatitis, cholestasis, hepatic failure. Immune system disorders: Allergic reactions (e.g. rash, oedema), anaphylactic shock. Investigations: Weight gain, abnormal hepatic function. Metabolism and nutrition disorders: Increased appetite, anorexia. Nervous system disorders: Drowsiness, headache, tremor, restlessness, paraesthesia, convulsion, disturbed coordination, neuritis. Psychiatric disorders: Confusion, insomnia, nervousness, hallucination, euphoria, irritability, aggressive behaviour, hysteria. Renal and urinary disorders: Urinary retention, frequency or difficulty in micturition. Reproductive system and breast disorders: Early menses. Respiratory, thoracic and mediastinal disorders: Dry nose and throat, chest tightness and wheezing, nasal stuffiness, epistaxis, thickened bronchial secretion. Skin and subcutaneous tissue disorders: Photosensitivity, urticaria, increased sweating.
This drug may cause dizziness, drowsiness, or sedation; if affected, do not drive or operate machinery.
Monitoring Parameters
Monitor weight periodically; excess anticholinergic effects at the start of treatment and periodically thereafter.
Overdosage
Symptoms: CNS depression to stimulation (e.g. hallucination, convulsions), respiratory and cardiac arrest, particularly in children; atropine-like (e.g. dry mouth, flushing; fixed, dilated pupils), and gastrointestinal symptoms. Management: Induce vomiting with ipecac syr, if vomiting has not occurred spontaneously. Perform gastric lavage with isotonic or half isotonic saline followed by administration of activated charcoal, if the patient is unable to vomit. May consider IV physostigmine salicylate for life-threatening CNS symptoms. May use saline cathartics to rapidly dilute bowel content; vasopressors for hypotension.
Drug Interactions
Additive effects with other CNS depressants (e.g. sedatives, hypnotics, tranquillisers, antianxiety drugs). May interfere with serotonin-enhancing antidepressants (e.g. SSRI) which may result in recurrence of depression and related symptoms. Potentially Fatal: Prolonged and intensified anticholinergic effects with MAOIs.
Food Interaction
Enhanced CNS depressant effects with alcohol.
Lab Interference
May suppress diagnostic skin antigen test results. May cause false-positive test result for TCAs in urine or serum during drug screen evaluation.
Action
Description: Mechanism of Action: Cyproheptadine is a potent 1st generation antihistamine with serotonin antagonist, sedative, anticholinergic, and Ca channel blocking properties. It competes with histamine for H1 receptor sites on effector cells in the blood vessels, gastrointestinal and respiratory tracts. Pharmacokinetics: Absorption: Well absorbed from the gastrointestinal tract. Time to peak plasma concentration: 6-9 hours (as metabolites). Metabolism: Almost completely metabolised in the liver via glucuronidation primarily to quaternary ammonium glucuronide conjugate. Undergoes aromatic ring hydroxylation, N-demethylation, and heterocyclic ring oxidation. Excretion: Mainly via urine (approx 40% mainly as metabolites); faeces (2-20%, <6% as unchanged drug). Elimination half-life: Approx 16 hours (as metabolites).
Chemical Structure
Cyproheptadine Source: National Center for Biotechnology Information. PubChem Compound Summary for CID 2913, Cyproheptadine. https://pubchem.ncbi.nlm.nih.gov/compound/Cyproheptadine. Accessed Oct. 27, 2020.
Anon. Cyproheptadine. AHFS Clinical Drug Information [online]. Bethesda, MD. American Society of Health-System Pharmacists, Inc. https://www.ahfscdi.com. Accessed 10/07/2020.Anon. Cyproheptadine. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 10/07/2020.Buckingham R (ed). Cyproheptadine Hydrochloride. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 10/07/2020.Cyproheptadine Hydrochloride Solution (Lannett Company, Inc.). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 10/07/2020.Cyproheptadine Hydrochloride Tablet (Amneal Pharmaceuticals of New York LLC). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 10/07/2020.Cyproheptadine. Gold Standard Drug Database in ClinicalKey [online]. Elsevier Inc. https://www.clinicalkey.com/. Accessed 10/07/2020.Joint Formulary Committee. Cyproheptadine Hydrochloride. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 10/07/2020.Periactin 4 mg Tablets (Teva UK Limited). MHRA. https://products.mhra.gov.uk/. Accessed 10/07/2020.
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