Generic Medicine Info
Indications and Dosage
Allergic conditions
Adult: 1 mg bid, increased up to Max 6 mg daily, if necessary. Max treatment duration: 14 days.
Child: 1-3 years 250-500 mcg bid; 3-6 years 500 mcg bid; 6-12 years 500-1000 mcg bid.
May be taken with or without food. May be taken w/ meals to reduce GI discomfort.
Lower respiratory disease including asthma, porphyria. Premature infants, neonates and children <1 year. Lactation. Concomitant use with MAOIs.
Special Precautions
Patients with history of asthma; CV diseases (e.g. hypertension, ischaemic heart disease); increased intra-ocular pressure or narrow-angle glaucoma; prostatic hypertrophy, bladder neck obstruction and/or genitourinary obstruction; pyloroduodenal obstruction including stenotic peptic ulcer; thyroid dysfunction; epilepsy or history of seizures. Children and elderly. Pregnancy.
Adverse Reactions
Significant: CNS depression (e.g. sedation, dizziness, drowsiness).
Gastrointestinal disorders: Epigastric distress.
General disorders and administration site conditions: Fatigue.
Nervous system disorders: Headache.
Patient Counseling Information
This drug may cause dizziness, drowsiness, and visual disturbances, if affected, do not drive or operate machinery.
Symptoms: CNS depression to stimulation, depressed level of consciousness, excitability, hallucinations, or convulsions. Anticholinergic symptoms (dry mouth, mydriasis, flushing, gastrointestinal reactions, and tachycardia) may occur. Management: Symptomatic treatment. Induce vomiting by giving a glass of water or milk. Perform gastric lavage with isotonic and 1/2 isotonic saline within 3 hours after ingestion. May give vasopressors in case of hypotension.
Drug Interactions
May potentiate anticholinergic activity of atropine and TCAs.
Potentially Fatal: Severe sedation and CNS depression with other CNS depressants (e.g. MAOIs, hypnotics, anxiolytics, opioid analgesics).
Food Interaction
Avoid alcohol.
Mechanism of Action: Clemastine competitively blocks H1-receptors sites on effector cells of the gastrointestinal tract, blood vessels and respiratory tract.
Onset: 2 hours.
Duration: 10-12 hours, up to 24 hours.
Absorption: Rapidly and almost completely absorbed from gastrointestinal tract. Bioavailability: Approx 40%. Time to peak plasma concentration: 2-4 hours.
Distribution: Enters the breast milk. Volume of distribution: Approx 800 L. Plasma protein binding: 95%.
Metabolism: Metabolised in the liver via O-dealkylation followed by alcohol degradation, aliphatic, aromatic, and direct oxidation. Subject to significant first pass metabolism.
Excretion: Mainly via urine (approx 42% as metabolites). Elimination half-life: Approx 21 hours.
Chemical Structure

Chemical Structure Image

Source: National Center for Biotechnology Information. PubChem Database. Clemastine, CID=26987, (accessed on Jan. 21, 2020)

Store between 20-25°C.
MIMS Class
Antihistamines & Antiallergics
ATC Classification
R06AA04 - clemastine ; Belongs to the class of aminoalkyl ethers used as systemic antihistamines.
Anon. Clemastine. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. Accessed 28/03/2019.

Buckingham R (ed). Clemastine. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. Accessed 28/03/2019.

Clemastine Fumarate Tablet (Teva Pharmaceuticals USA, Inc.). DailyMed. Source: U.S. National Library of Medicine. Accessed 28/03/2019.

Joint Formulary Committee. Clemastine. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. Accessed 28/03/2019.

Disclaimer: This information is independently developed by MIMS based on Clemastine from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to MIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, MIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2024 MIMS. All rights reserved. Powered by
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