Clemastine Side Effects

Please note - some side effects for Clemastine may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA at http://www.fda.gov/medwatch/ or 1-800-FDA-1088 (1-800-332-1088).

Side Effects of Clemastine - for the Consumer

Clemastine

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome when using Clemastine:

Dizziness; drowsiness; dry mouth, throat, and nose; excitability; thickening of mucus in nose or throat.

Severe allergic reactions (rash; hives; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); convulsions; fast heartbeat or pounding in the chest; decreased alertness; hallucinations; tremor; wheezing.

Clemastine Syrup

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome when using Clemastine Syrup:

Dizziness; drowsiness; dry mouth, throat, and nose; excitability; thickening of mucus in nose or throat.

Severe allergic reactions (rash; hives; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); convulsions; fast heartbeat or pounding in the chest; decreased alertness; hallucinations; tremor; wheezing.

Clemastine Side Effects - for the Professional

Clemastine

Transient drowsiness, the most common adverse reaction associated with Clemastine fumarate, occurs relatively frequently and may require discontinuation of therapy in some instances.

Antihistaminic Compounds

It should be noted that the following reactions have occurred with one or more antihistamines and, therefore, should be kept in mind when prescribing drugs belonging to this class, including Clemastine fumarate.

The most frequent adverse reactions are underlined.

1. General: Urticaria, drug rash, anaphylactic shock, photosensitivity, excessive perspiration, chills, dryness of mouth, nose, and throat.
2. Cardiovascular System: Hypotension, headache, palpitations, tachycardia, extrasystoles.
3. Hematologic System: Hemolytic anemia, thrombocytopenia, agranulocytosis.
4. 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.
5. GI System: Epigastric distress, anorexia, nausea, vomiting, diarrhea, constipation.
6. GU System: Urinary frequency, difficult urination, urinary retention, early menses.
7. Respiratory System: Thickening of bronchial secretions, tightness of chest and wheezing, nasal stuffiness.

Side Effects by Body System

Nervous system

Nervous system side effects have included central nervous system depression which has commonly resulted in drowsiness, dizziness, and headache. Dyskinesias have rarely been reported following chronic use of antihistamines.

Nearly all patients experience drowsiness. This drowsiness may subside in some patients with extended use. Patients should be warned against driving, as well as concomitant ingestion with alcohol and other sedative-hypnotic drugs.

Few cases of dyskinesias and tremors, often of the face, have been reported in patients whose chronic use of antihistamines extended over a period of 3 to 10 years. Some of these cases were only partially relieved by discontinuation of the drug. Haloperidol was successful in relieving symptoms.

Gastrointestinal

Gastrointestinal side effects have included dry mouth and constipation due to anticholinergic effects. This has occurred in up to one-third of patients.

Cardiovascular

Cardiovascular side effects have included hypotension, tachycardia, and palpitations.

Ocular

Ocular effects are due to the anticholinergic effects and may include blurred vision, diplopia, and dry eyes.

Genitourinary

Genitourinary side effects have included dysuria, urinary hesitancy, decrease in urine flow, and in rare cases, acute urinary retention.

Hematologic

Hematologic side effects that have been reported with antihistamines include bone marrow suppression, thrombocytopenia, and aplastic anemia.

A fatal case of agranulocytosis has been reported in a patient taking chlorpheniramine, pseudoephedrine, acetaminophen, dextromethorphan, phenylpropanolamine, and aspirin. Chlorpheniramine was felt to be the cause.

Respiratory

Respiratory side effects have included thickening of bronchial secretions, wheezing, and tightness in the chest.

Dermatologic

At least one case of toxic pustuloderma has been reported during clemastine therapy.

Dermatologic side effects have included toxic pustuloderma.

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