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, tachy-cardia, 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.

Read the Clemastine Fumarate Tablets (clemastine fumarate tablets) Side Effects Center for a complete guide to possible side effects »

MAO inhibitors prolong and intensify the anticholiner-gic (drying) effects of antihistamines.

Last reviewed on RxList: 8/11/2008
This monograph has been modified to include the generic and brand name in many instances.