Clemastine fumarate

What Clemastine fumarate is used for

Quoted from the “Indications and Usage” section of the FDA-approved label.

Clemastine Fumarate Syrup is indicated for the relief of symptoms associated with allergic rhinitis such as sneezing, rhinorrhea, pruritus and lacrimation. Clemastine Fumarate Syrup is indicated for use in pediatric populations (age 6 years through 12) and adults (see DOSAGE AND ADMINISTRATION ). …

— FDA label: Clemastine Fumarate, Genus Lifesciences, effective November 25, 2024. Read the full label on DailyMed →

Label quoted: the one for the most common form (syrup, oral), Clemastine Fumarate, Genus Lifesciences; it covers 1 product in the FDA NDC Directory. The side effects, interactions, dosage and pregnancy quotes below come from this same label.

The FDA has 3 labels for products of this medicine (different makers and forms); uses can differ between them. Check the label that comes with your own medicine.

This page is not medical advice. Talk to your doctor or pharmacist before you start, stop or change any medicine.

Boxed warning

A boxed warning (“black box”) is the FDA’s strongest warning on a drug label, for serious or life-threatening risks.

The label quoted above has no boxed warning.

0 of 3 FDA labels for this medicine have a boxed warning.

Clemastine fumarate side effects

Quoted from the “Adverse Reactions” section of the FDA-approved label. Tell your doctor about any side effect that worries you.

The most frequent adverse reactions are italicized: Nervous System Sedation, sleepiness, dizziness, disturbed coordination, fatigue, confusion, restlessness, excitation, nervousness, tremor, irritability, insomnia, euphoria, paresthesia, blurred vision, diplopia, vertigo, tinnitus, acute labyrinthitis, hysteria, neuritis, convulsions. Gastrointestinal System Epigastric distress, anorexia, nausea, vomiting, diarrhea, constipation.

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Respiratory System Thickening of bronchial secretions, tightness of chest and wheezing, nasal stuffiness. Cardiovascular System Hypotension, headache, palpitations, tachycardia, extrasystoles. Hematologic System Hemolytic anemia, thrombocytopenia, agranulocytosis. Genitourinary System Urinary frequency, difficult urination, urinary retention, early menses. General Urticaria, drug rash, anaphylactic shock, photosensitivity, excessive perspiration, chills, dryness of mouth, nose and throat. To report SUSPECTED ADVERSE REACTIONS, contact Allucent at 1-866-511-6754 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

— FDA label: Clemastine Fumarate, Genus Lifesciences, effective November 25, 2024. Read the full label on DailyMed →

Clemastine fumarate drug interactions

Quoted from the “Drug Interactions” section of the FDA-approved label. Tell your pharmacist about every medicine, vitamin and herbal product you take.

Additive CNS depression may occur when antihistamines are administered concomitantly with other CNS depressants including barbiturates, tranquilizers, and alcohol. Patients receiving antihistamines should be advised against the concurrent use of other CNS depressant drugs. Monoamine oxidase (MAO) inhibitors prolong and intensify the anticholinergic effects of antihistamines.

— FDA label: Clemastine Fumarate, Genus Lifesciences, effective November 25, 2024. Read the full label on DailyMed →

Clemastine fumarate dosage

Quoted from the “Dosage and Administration” section of the FDA-approved label. Your own dose is the one your doctor prescribes: do not change it on your own.

DOSAGE SHOULD BE INDIVIDUALIZED ACCORDING TO THE NEEDS AND RESPONSE OF THE PATIENT. Pediatric Children aged 6 to 12 years For Symptoms of Allergic Rhinitis The starting dose is 1 teaspoonful (0.5 mg clemastine) twice daily. Since single doses of up to 2.25 mg clemastine were well tolerated by this age group, dosage may be increased as required, but not to exceed 6 teaspoonfuls daily (3 mg clemastine).

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For Urticaria and Angioedema The starting dose is 2 teaspoonfuls (1 mg clemastine) twice daily, not to exceed 6 teaspoonfuls daily (3 mg clemastine). Adults and Children 12 Years and Over For Symptoms of Allergic Rhinitis The starting dose is 2 teaspoonfuls (1 mg clemastine) twice daily. Dosage may be increased as required, but not to exceed 12 teaspoonfuls daily (6 mg clemastine). For Urticaria and Angioedema The starting dose is 4 teaspoonfuls (2 mg clemastine) twice daily, not to exceed 12 teaspoonfuls daily (6 mg clemastine).

— FDA label: Clemastine Fumarate, Genus Lifesciences, effective November 25, 2024. Read the full label on DailyMed →

Clemastine fumarate in pregnancy

Quoted from the pregnancy part of the FDA-approved label. Ask your doctor before you take any medicine while pregnant or planning a pregnancy.

Teratogenic Effects Pregnancy Category B Oral reproduction studies performed with clemastine fumarate in rats and rabbits at doses up to 312 and 188 times the adult human doses respectively, have revealed no evidence of teratogenic effects. There are no adequate and well-controlled studies of clemastine fumarate in pregnant women. Because animal reproduction studies are not always predictive of human response, this drug should be used in pregnancy only if clearly needed.

— FDA label: Clemastine Fumarate, Genus Lifesciences, effective November 25, 2024. Read the full label on DailyMed →

Clemastine fumarate and breastfeeding

Quoted from the nursing mothers / lactation part of the FDA-approved label.

Although quantitative determinations of antihistaminic drugs in breast milk have not been reported, qualitative tests have documented the excretion of diphenhydramine, pyrilamine, and tripelennamine in human milk. Because of the potential for adverse reactions in nursing infants from antihistamines, a decision should be made whether to discontinue nursing or to discontinue the drug.

— FDA label: Clemastine Fumarate, Genus Lifesciences, effective November 25, 2024. Read the full label on DailyMed →

When Clemastine fumarate should not be used

Quoted from the “Contraindications” section of the FDA-approved label.

Antihistamines are contraindicated in patients hypersensitive to the drug or to other antihistamines of similar chemical structure (see PRECAUTIONS- Drug Interactions). Antihistamines 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 (see PRECAUTIONS-Nursing Mothers).

— FDA label: Clemastine Fumarate, Genus Lifesciences, effective November 25, 2024. Read the full label on DailyMed →

Clemastine fumarate overdose

Quoted from the “Overdosage” section of the FDA-approved label. If someone may have taken too much, call Poison Help at 1-800-222-1222 (or 911 in an emergency).

Antihistamine overdosage reactions may vary from central nervous system depression to stimulation. In children, stimulation predominates initially in a syndrome which may include excitement, hallucinations, ataxia, incoordination, muscle twitching, athetosis, hyperthermia, cyanosis convulsions, tremors, and hyperreflexia followed by postictal depression and cardio-respiratory arrest. Convulsions in children may be preceded by mild depression.

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Dry mouth, fixed dilated pupils, flushing of the face, and fever are common. In adults, CNS depression, ranging from drowsiness to coma, is more common. The convulsant dose of antihistamines lies near the lethal dose. Convulsions indicate a poor prognosis. In both children and adults, coma and cardiovascular collapse may occur. Deaths are reported especially in infants and children. There is no specific therapy for acute overdosage with antihistamines. The latent period from ingestion to appearance of toxic effects is characteristically short (1/2-2 hours). General symptomatic and supportive measures should be instituted promptly and maintained for as long as necessary. Since overdoses of other classes of drugs (i.e. tricyclic antidepressants) may also present anticholinergic symptomatology, appropriate toxicological analysis should be performed as soon as possible to identify the causative agent. In the conscious patient, vomiting should be induced even though it may have occurred spontaneously. If vomiting cannot be induced, gastric lavage is indicated. Adequate precautions must be taken to protect against aspiration, especially in infants and children. Charcoal slurry or other suitable agents should be instilled into the stomach after vomiting or lavage. Saline cathartics or milk of magnesia may be of additional benefit. In the unconscious patient, the airway should be secured with a cuffed endotracheal tube before attempting to evacuate the gastric contents. Intensive supportive and nursing care is indicated, as for any comatose patient. If breathing is significantly impaired, maintenance of an adequate airway and mechanical support of respiration is the most effective means of providing adequate oxygenation. Hypotension is an early sign of impending cardiovascular collapse and should be treated vigorously. Although general supportive measures are important, specific treatment with intravenous infusion of a vasopressor titrated to maintain adequate blood pressure may be necessary. Do not use with CNS stimulants. Convulsions should be controlled by careful administration of diazepam or a short-acting barbiturate, repeated as necessary. Physostigmine may also be considered for use in controlling centrally mediated convulsions. Ice packs and cooling sponge baths, not alcohol, can aid in reducing the fever commonly seen in children. A more detailed review of antihistamine toxicology and overdose management is available in Gosselin, R.E., et. al., "Clinical Toxicology of Commercial Products."

— FDA label: Clemastine Fumarate, Genus Lifesciences, effective November 25, 2024. Read the full label on DailyMed →

Forms and how it is given

Companies that list this medicine

Labelers in the FDA NDC Directory: the company named on the package (maker or distributor), with the number of prescription products.

• Genus Lifesciences2 products
• Chartwell RX, LLC1 product
• IPG Pharmaceuticals, Inc.1 product

FDA approval history

• ANDA: Abbreviated New Drug Application: how a generic version is approved.

Generic approvals (3)

• ANDA073283Genus · January 31, 1992
• ANDA073399Genus · June 30, 1994
• ANDA074884Genus Lifesciences · December 17, 1997

Shortage status

The FDA drug shortage list does not show these products.

FDA Drug Shortages database →

Recalls

No recall linked to these products (by their NDC code) appears in the FDA enforcement reports.

Official identifiers

Next steps

• Find a pharmacy near youAsk which price applies to you and whether your product is affected by a recall
• Latest FDA drug recallsAll medicines, newest first
• ClemszaBrand page: products, maker and price
• Genus LifesciencesMaker or distributor
• Chartwell RX, LLCMaker or distributor
• IPG Pharmaceuticals, Inc.Maker or distributor
• All prescription drugs A to ZSearch by generic, brand or Spanish name

Sources

1. FDA-approved label on DailyMed (National Library of Medicine) — Clemastine Fumarate, Genus Lifesciences, effective November 25, 2024; via openFDA, FDA data exported October 30, 2026, retrieved October 31, 2026
2. NDC Directory (openFDA) — U.S. Food and Drug Administration (FDA), FDA data exported October 30, 2026, retrieved October 31, 2026
3. Drugs@FDA (openFDA) — U.S. Food and Drug Administration (FDA), FDA data exported October 30, 2026, retrieved October 31, 2026
4. Drug recall enforcement reports (openFDA) — U.S. Food and Drug Administration (FDA), FDA data exported October 27, 2026, retrieved October 31, 2026
5. Drug shortages (openFDA) — U.S. Food and Drug Administration (FDA), FDA data exported October 30, 2026, retrieved October 31, 2026

openFDA data is provided by the FDA as is; it may be incomplete. Always rely on the label that comes with your medicine. FDA Enforcement Report search →

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