Clemastine

What is Clemastine?

• Clemastine (Dayhist Allergy; Tavist; Tavist Allergy) is an antihistamine with anticholinergic (drying) and sedative side effects.

Clemastine

Clemastine

Clemastine ball-and-stick

What are the uses of this medicine?

• Clemastine (Dayhist Allergy; Tavist; Tavist Allergy) is used for the relief of symptoms associated with allergic rhinitis such as sneezing, rhinorrhea, pruritus, and lacrimation.
• It is also used for the relief of mild, uncomplicated allergic skin manifestations of urticaria and angioedema.

Limitations of use:

• Clemastine helps control symptoms of allergies and colds but does not treat the cause of these symptoms or speed recovery.

How does this medicine work?

• A synthetic ethanolamine with anticholinergic, sedative, and histamine H1 antagonistic properties.
• Clemastine fumarate blocks the H1 histamine receptor and prevents the symptoms that are caused by histamine activity on capillaries, bronchial and gastrointestinal smooth muscles, including vasodilation, increased capillary permeability, bronchoconstriction, and spasmodic contraction of gastrointestinal smooth muscles.
• This drug also prevents histamine-induced pain and itching of mucous membranes.

Who Should Not Use this medicine ?

This medicine cannot be used:

• in nursing mothers.
• in Lower Respiratory Disease

Antihistamines are also contraindicated in the following conditions:

• Hypersensitivity to clemastine fumarate or other antihistamines of similar chemical structure.
• Monoamine oxidase inhibitor therapy.

What drug interactions can this medicine cause?

• Tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take.

Be sure to mention any of the following:

• other medications for colds, hay fever, or allergies; medications for depression or seizures; muscle relaxants; narcotic medications for pain; sedatives; sleeping pills; and tranquilizers.

• Tell your doctor if you are taking monoamine oxidase (MAO) inhibitors such as isocarboxazid (Marplan), phenelzine (Nardil), selegiline (Eldepryl, Emsam, Zelapar), and tranylcypromine (Parnate).

Is this medicine FDA approved?

• Patented in 1960, it came into medical use in 1967.

How should this medicine be used?

Recommended dosage:

Clemastine Fumarate Tablets 2.68 mg:

• The maximum recommended dosage is one tablet three times daily.
• Many patients respond favorably to a single dose which may be repeated as required, but not to exceed three tablets daily.

Administration:

• Clemastine comes as a tablet and a liquid to take by mouth.
• It is usually taken two or three times a day.
• Take clemastine exactly as directed.
• Do not take more or less of it or take it more often than prescribed by your doctor or directed by the label.
• If you are taking the liquid, do not use a household spoon to measure your dose.
• Use the measuring spoon or cup that came with the medication or use a spoon made especially for measuring medication.

What are the dosage forms and brand names of this medicine?

This medicine is available in fallowing doasage form:

• As a tablet and a liquid

This medicine is available in fallowing brand namesː

• Dayhist Allergy; Tavist; Tavist Allergy

What side effects can this medication cause?

The most common side effects of this medicine may include:

• sedation, impairment of motor function, confusion, dizziness, blurred vision, dry mouth and throat, palpitations, tachycardia, abdominal distress, constipation and headache.

• Antihistamines can worsen urinary retention and precipitate acute narrow angle glaucoma.

Less common, but serious side effects may include:

• General: Urticaria, drug rash, anaphylactic shock, photosensitivity, excessive perspiration, chills, dryness of the mouth, nose, and throat.
• Cardiovascular System: Hypotension, headache, palpitations, tachycardia, extrasystoles.
• Hematologic System: Hemolytic anemia, thrombocytopenia, agranulocytosis.
• Nervous System: Sedation, sleepiness, dizziness, disturbed coordination, fatigue, confusion, restlessness, excitation, nervousness, tremor, irritability, insomnia, euphoria, paresthesias, blurred vision, diplopia, vertigo, tinnitus, acute labyrinthitis, hysteria, neuritis, convulsions.
• GI System: Epigastric distress, anorexia, nausea, vomiting, diarrhea, constipation.
• GU System: Urinary frequency, difficult urination, urinary retention, early menses.
• Respiratory System: Thickening of bronchial secretions, tightness of chest and wheezing, nasal stuffiness.

What special precautions should I follow?

• Antihistamines should be used with considerable caution in patients with: narrow angle glaucoma, stenosing peptic ulcer, pyloroduodenal obstruction, symptomatic prostatic hypertrophy, and bladder neck obstruction.
• Clemastine has additive effects with alcohol and other CNS depressants (hypnotics, sedatives, tranquilizers, etc.).
• Patients should be warned about engaging in activities requiring mental alertness such as driving a car or operating appliances, machinery, etc.
• Antihistamines are more likely to cause dizziness, sedation, and hypotension in elderly patients.
• MAO inhibitors prolong and intensify the anticholinergic (drying) effects of antihistamines.
• Because of the higher risk of antihistamines for infants generally and for newborns and prematures in particular, antihistamine therapy is contraindicated in nursing mothers.

What to do in case of emergency/overdose?

Symptoms of overdosage may include:

• central nervous system depression to stimulation. Stimulation is particularly likely in children.
• Atropine-like signs and symptoms: dry mouth; fixed, dilated pupils; flushing; and gastrointestinal symptoms may also occur.

Management of overdosage:

• In case of overdose, call the poison control helpline of your country. In the United States, call 1-800-222-1222.

• Overdose related information is also available online at poisonhelp.org/help.
• In the event that the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services. In the United States, call 911.
• If vomiting has not occurred spontaneously the conscious patient should be induced to vomit.
• This is best done by having him drink a glass of water or milk after which he should be made to gag.
• Precautions against aspiration must be taken, especially in infants and children.
• If vomiting is unsuccessful gastric lavage is indicated within 3 hours after ingestion and even later if large amounts of milk or cream were given beforehand.
• Isotonic and 1/2 isotonic saline is the lavage solution of choice.
• Saline cathartics, such as milk of magnesia, by osmosis draw water into the bowel and therefore, are valuable for their action in rapid dilution of bowel content.
• Stimulants should not be used.
• Vasopressors may be used to treat hypotension.

Can this medicine be used in pregnancy?

• Experience with this drug in pregnant women is inadequate to determine whether there exists a potential for harm to the developing fetus.

Can this medicine be used in children?

• Safety and efficacy of clemastine fumarate have not been established in children under the age of 12 years.

What are the active and inactive ingredients in this medicine?

Active ingredient:

• clemastine fumarate

Inactive ingredients:

• silicon dioxide
• starch, corn
• lactose, unspecified form
• povidone k30
• stearic acid

Who manufactures and distributes this medicine?

Manufactured For:

• Teva Pharmaceuticals
• Parsippany, NJ

What should I know about storage and disposal of this medication?

• Store at 20o to 25oC (68o to 77oF).
• Dispense in a tight, light-resistant container as defined in the USP, with a child-resistant closure (as required).

First Generation Antihistamines

• Brompheniramine
• Carbinoxamine
• Chlorcyclizine
• Chlorpheniramine
• Clemastine
• Cyclizine
• Cyproheptadine
• Dexbrompheniramine
• Dexchlorpheniramine
• Dimenhydrinate
• Diphenhydramine
• Doxylamine
• Hydroxyzine
• Meclizine
• Phenyltoloxamine
• Promethazine
• Triprolidine

Second Generation Antihistamines

• Acrivastine
• Cetirizine
• Fexofenadine
• Levocetirizine
• Loratadine
• Desloratadine

• Dailymed label info on Clemastine
• FDA Clemastine

First Generation Antihistamines

• Brompheniramine
• Carbinoxamine
• Chlorcyclizine
• Chlorpheniramine
• Clemastine
• Cyclizine
• Cyproheptadine
• Dexbrompheniramine
• Dexchlorpheniramine
• Dimenhydrinate
• Diphenhydramine
• Doxylamine
• Hydroxyzine
• Meclizine
• Phenyltoloxamine
• Promethazine
• Triprolidine

Second Generation Antihistamines

• Acrivastine
• Cetirizine
• Fexofenadine
• Levocetirizine
• Loratadine
• Desloratadine

Pharmacodynamics