Class: First Generation Antihistamines
ATC Class: R06AA04
VA Class: AH102
CAS Number: 14976-57-9
Brands: Dayhist, Tavist
Introduction
First generation antihistamine; an ethanolamine derivative.101 102 103 a b
Uses for Clemastine Fumarate
Allergic Rhinitis
Symptomatic relief of rhinorrhea, sneezing, lacrimation, itching eyes, or oronasopharyngeal itching associated with allergic rhinitis (e.g., hay fever) or other upper respiratory allergies.101 102 103 104 105 a
Allergic Skin Disorders
Management of mild, uncomplicated allergic skin manifestations of urticaria and angioedema.101 102 103 a
Common Cold
Self-medication for temporary relief of symptoms associated with the common cold (e.g., rhinorrhea, sneezing).105 a
Clemastine Fumarate Dosage and Administration
Administration
Oral Administration
Administer orally as tablets or oral solution.101 102 103 a
Dosage
Available as clemastine fumarate; dosage expressed in terms of the salt.101 102 103 104
1.34 mg clemastine fumarate equivalent to 1 mg clemastine.101 103 104 105 a
Individualize dosage according to patient’s response and tolerance.101 102 103 a b
Pediatric Patients
Allergic Conditions
Allergic Rhinitis
Oral
Children 6 to <12 years of age: Initially, 0.67 mg twice daily (as oral solution).101 103 a Because single doses of up to 3.02 mg have been well tolerated, may increase dosage as necessary, not to exceed 4.02 mg daily.101 103 a
Children ≥12 years of age: 1.34 mg every 12 hours (as tablets or oral solution); this is the maximum dosage recommended for self-medication.104 105 a When used under the direction of a clinician, may increase dosage as necessary, not to exceed 8.04 mg daily.101 102 103 a
Allergic Skin Disorders
Oral
Children 6 to <12 years of age: Initially, 1.34 mg twice daily (as oral solution).101 May increase dosage as necessary, not to exceed 4.02 mg daily.101 103 a
Children ≥12 years of age: 2.68 mg 1–3 times daily (as tablets or oral solution), not to exceed 8.04 mg daily.101 102 103 a
Common Cold
Oral
Self-medication in children ≥12 years of age: Usually, 1.34 mg every 12 hours (as tablets), not to exceed 2.68 mg daily unless otherwise directed by a clinician.a
Adults
Allergic Conditions
Allergic Rhinitis
Oral
Initially, 1.34 mg every 12 hours (as tablets or oral solution); this is the maximum dosage recommended for self-medication.a When used under the direction of a clinician, may increase dosage as necessary, not to exceed 8.04 mg daily.101 102 103 a
Allergic Skin Disorders
Oral
2.68 mg 1–3 times daily (as tablets or oral solution), not to exceed 8.04 mg daily.101 102 103 a
Common Cold
Oral
Self-medication: Usually, 1.34 mg every 12 hours (as tablets), not to exceed 2.68 mg daily unless otherwise directed by a clinician.a
Prescribing Limits
Pediatric Patients
Allergic Conditions
Allergic Rhinitis
Oral
Children 6 to <12 years of age: Maximum 4.02 mg daily.101 a
Children ≥12 years of age: For self-medication, maximum 1.34 mg every 12 hours.a When used under the direction of a clinician, maximum 8.04 mg daily.101 102 a
Allergic Skin Disorders
Oral
Children 6 to <12 years of age: Maximum 4.02 mg daily.101 a
Children ≥12 years of age: Maximum 8.04 mg daily.101 102 a
Common Cold
Oral
Children ≥12 years of age: For self-medication, maximum 2.68 mg daily unless otherwise directed by a clinician.a
Adults
Allergic Conditions
Allergic Rhinitis
Oral
Self-medication: Maximum 1.34 mg every 12 hours.a When used under the direction of a clinician, maximum 8.04 mg daily.101 102 a
Allergic Skin Disorders
Oral
Maximum 8.04 mg daily.101 102 a
Common Cold
Oral
Self-medication: Maximum 2.68 mg daily unless otherwise directed by a clinician.a
Special Populations
Geriatric Patients
Reduce dosage if mild adverse effects occur.b (See Geriatric Use under Cautions.)
Cautions for Clemastine Fumarate
Contraindications
Use contraindicated in neonates and premature infants.101 103 a (See Pediatric Use under Cautions.)
Women who are breast-feeding.101 102 103 (See Lactation under Cautions.)
Patients receiving MAO inhibitor therapy.102 (See Interactions.)
Known hypersensitivity to clemastine, other antihistamines with similar chemical structure, or any ingredient in the formulation.101 102 103
Warnings/Precautions
Warnings
Concomitant Diseases
Because of anticholinergic effects, use with extreme caution in patients with angle-closure glaucoma, stenosing peptic ulcer, pyloroduodenal obstruction, bladder neck obstruction, or symptomatic prostatic hypertrophy.101 102 103 b
Use with caution in patients with history of bronchial asthma, increased IOP, hyperthyroidism, or cardiovascular disease (e.g., hypertension).101 102 103
CNS Effects
Risk of drowsiness.101 103 b (See CNS Depressants under Interactions and also see Advice to Patients.)
Possible excitability (especially in children).104 105 b (See Pediatric Use under Cautions.)
Specific Populations
Pregnancy
Category B.101 103 106
Lactation
Distributed into milk. Some manufacturers recommend discontinuance of nursing or the drug because of potential risk to nursing infants (see Contraindications under Cautions).101 102 103 However, AAP states that the drug may be used with caution during breast-feeding.106
Pediatric Use
Contraindicated in neonates and premature infants.101 103 a
Possible paradoxical excitement (e.g., restlessness, insomnia, tremors, euphoria, nervousness, delirium, palpitation, seizures), especially in children.104 105 b
Safety and efficacy of tablets not established in children <12 years of age.102 a Safety and efficacy of oral solution not established in children <6 years of age.101 103 a
Risk of overdosage and toxicity (including death) in children <2 years of age receiving OTC preparations containing antihistamines, cough suppressants, expectorants, and nasal decongestants alone or in combination for relief of symptoms of upper respiratory tract infection. Limited evidence of efficacy for these preparations in this age group; appropriate dosages not established. Therefore, FDA recommended not to use such preparations in children <2 years of age; safety and efficacy in older children currently under evaluation. Because children 2–3 years of age also are at increased risk of overdosage and toxicity, some manufacturers of oral nonprescription cough and cold preparations recently agreed to voluntarily revise the product labeling to state that such preparations should not be used in children <4 years of age. During the transition period, some preparations on pharmacy shelves will have the new recommendation (“do not use in children <4 years of age”), while others will have the previous recommendation (“do not use in children <2 years of age”). FDA recommends that parents and caregivers adhere to dosage instructions and warnings on the product labeling that accompanies the preparation and consult a clinician about . Clinicians should ask caregivers about use of OTC cough/cold preparations to avoid overdosage.
Geriatric Use
Possible increased risk of dizziness, sedation, and hypotension in patients ≥60 years of age.101 102 103 (See Geriatric Patients under Dosage and Administration.)
Common Adverse Effects
Sedation,101 102 103 sleepiness,101 102 103 dizziness,101 102 103 disturbed coordination,101 102 103 epigastric distress,101 102 103 thickening of bronchial secretions.101 102 103
Interactions for Clemastine Fumarate
Specific Drugs and Laboratory Tests
Drug or Test | Interaction | Comments |
|---|---|---|
CNS depressants (e.g., alcohol, hypnotics, sedatives, tranquilizers) | Possible additive CNS depression101 102 103 104 105 b | Avoid concomitant use101 103 |
MAO inhibitors | MAO inhibitors prolong and intensify anticholinergic effects of antihistamines101 102 103 b | Concomitant use contraindicated102 |
Test, antigen or histamine | Inhalation-challenge testing with histamine or antigen: Possible suppression of test response Antigen skin testing: Possible suppression of wheal and flare reactions |
Clemastine Fumarate Pharmacokinetics
Absorption
Bioavailability
Rapidly and almost completely absorbed from the GI tract.101 102 103 a
Peak plasma concentrations achieved within 2–5 hours following oral administration.101 102 103
Onset
Antihistaminic effect is maximal within 5–7 hours.101 102 103
Duration
Antihistaminic effect persists for 10–12 hours and, in some individuals, up to 24 hours.101 102 103
Distribution
Extent
Distribution into human body fluids and tissues not fully characterized.
Distributed into milk.
Elimination
Metabolism
Exact metabolic fate not clearly established, but appears to be extensively metabolized.
Elimination Route
Excreted principally in urine as unchanged drug and metabolites.101 102 103
Stability
Storage
Oral
Tablets
Tight, light-resistant containers at 20–25°C.102
Oral Solution
Tight, light-resistant, upright containers103 at 20–25°C.101 103
ActionsActions
Blocks H1-receptor sites, thereby preventing the action of histamine on the cell.101 103 b
Suppresses flare and pruritus that accompany the endogenous release of histamine.101 b
Has anticholinergic and sedative effects.101 102 103
Antihistamines do not block the stimulating effect of histamine on gastric acid secretion, which is mediated by H2-receptors of the parietal cells.b
Advice to Patients
Risk of drowsiness; avoid alcohol and avoid engaging in hazardous tasks (e.g., operating machinery, driving a motor vehicle) until effects on individual are known.101 102 103 104 105
Importance of informing clinicians of existing or contemplated concomitant therapy, including prescription and OTC drugs and dietary or herbal supplements, as well as any concomitant illnesses.101 102 103 Importance of patients already receiving another CNS depressant (e.g., sedative, tranquilizer) not undertaking self-medication without first consulting a clinician.104
Importance of women informing clinicians if they are or plan to become pregnant or plan to breast-feed.101 102 103
Importance of informing patients of other important precautionary information.101 102 103 (See Cautions.)
Preparations
Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.
* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name
Routes | Dosage Forms | Strengths | Brand Names | Manufacturer |
|---|---|---|---|---|
Oral | Solution | 0.67 mg/5 mL* | Clemastine Fumarate Syrup | |
Tablets | 1.34 mg* | Clemastine Fumarate Tablets | ||
Dayhist Allergy | Major | |||
Tavist Allergy (formerly Tavist-1) (scored) | Novartis | |||
2.68 mg* | Clemastine Fumarate Tablets (scored) |
Comparative Pricing
This pricing information is subject to change at the sole discretion of DS Pharmacy. This pricing information was updated 03/2011. Actual costs to patients will vary depending on the use of specific retail or mail-order locations and health insurance copays.
Clemastine Fumarate 1.34MG Tablets (SANDOZ): 100/$25.99 or 300/$69.97
Clemastine Fumarate 2.68MG Tablets (SANDOZ): 30/$17.98 or 60/$27.97
Disclaimer
This report on medications is for your information only, and is not considered individual patient advice. Because of the changing nature of drug information, please consult your physician or pharmacist about specific clinical use.
The American Society of Health-System Pharmacists, Inc. and Drugs.com represent that the information provided hereunder was formulated with a reasonable standard of care, and in conformity with professional standards in the field. The American Society of Health-System Pharmacists, Inc. and Drugs.com make no representations or warranties, express or implied, including, but not limited to, any implied warranty of merchantability and/or fitness for a particular purpose, with respect to such information and specifically disclaims all such warranties. Users are advised that decisions regarding drug therapy are complex medical decisions requiring the independent, informed decision of an appropriate health care professional, and the information is provided for informational purposes only. The entire monograph for a drug should be reviewed for a thorough understanding of the drug's actions, uses and side effects. The American Society of Health-System Pharmacists, Inc. and Drugs.com do not endorse or recommend the use of any drug. The information is not a substitute for medical care.
AHFS Drug Information. © Copyright, 1959-2011, Selected Revisions November 2008. American Society of Health-System Pharmacists, Inc., 7272 Wisconsin Avenue, Bethesda, Maryland 20814.
References
101. Teva Pharmaceuticals. Clemastine fumarate syrup prescribing information. Sellersville, PA; 2003 Apr.
102. Teva Pharmaceuticals. Clemastine fumarate tablets prescribing information. Sellersville, PA; 2003 Aug.
103. Major Pharmaceuticals. Clemastine fumarate syrup prescribing information. Livonia, MI; 2001 May.
104. Major Pharmaceuticals. Dayhist Allergy product information. Livonia, MI. From Major Pharmaceuticals website (). Accessed 2008 Jan 17.
105. Novartis. East Hanover, NJ: Personal communication.
106. Clemastine. In: Briggs GG, Freeman RK, Yaffe SJ. Drugs in pregnancy and lactation. 7th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2005:341-2.
a. AHFS Drug Information 2008. McEvoy GK, ed. Clemastine Fumarate. Bethesda, MD: American Society of Health-System Pharmacists; 2008:14-5.
b. AHFS Drug Information 2008. McEvoy GK, ed. Antihistamines General Statement. Bethesda, MD: American Society of Health-System Pharmacists; 2008:1-8.
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