Clemastine is a medication commonly prescribed to treat allergy symptoms. It may help relieve red, itchy eyes, sneezing, and runny nose. This medication is an antihistamine that works by interfering with a natural chemical produced in the body, called histamine. There are two different formulas for this drug: one is prescription-strength and the other may be sold over-the-counter. Clemastine should work to relieve allergy symptoms no more than three days after beginning treatment, but if it does not, patients should seek the advice of their physicians.
This medication is available as a chewable tablet, a regular tablet, or a syrup. It is typically taken two to three times daily; however, the maximum daily dosage should not exceed 8.04 milligrams (mg). Patients should take clemastine with a full glass of water and they may take it with or without food. Those using the syrup should measure it with a medicine cup, rather than a regular spoon to ensure proper dosage. The chewable tablets must be thoroughly chewed before swallowing.
Some side effects may be experienced with the use of clemastine, which should be reported to the physician if they are persistent or become troublesome. Excitement may occur, especially in children, as well as nervousness and drowsiness. Dizziness, loss of coordination, and a headache have also been reported. Some patients may experience a dry throat, nose, and mouth, as well as chest congestion and nausea.
Most patients will typically not experience serious side effects while taking clemastine, however they are possible. Signs of a potential allergic reaction can include facial swelling, problems breathing, and severe dizziness, as well as a rash. Other serious side effects may include a rapid or irregular heartbeat, problems swallowing, and changes in vision. Difficulty urinating can also be a sign of complications from clemastine.
Patients must be careful to not exceed the recommended dosage of clemastine. Those who do overdose should seek emergency medical care. Symptoms of a possible overdose can include weakness, shaking, and hallucinations. Extreme sleepiness, confusion, and blurred vision may also occur as well as flushing, fever, and large pupils.
The use of alcohol should be avoided or reduced while taking this drug, because this can increase certain side effects, like drowsiness or dizziness. Before using clemastine, patients should disclose their other medical conditions. Patients may be unable to use this antihistamine drug if they have heart problems, high blood pressure, or glaucoma. Stomach ulcers, an enlarged prostate, and hyperthyroidism may also preclude a person from taking it. While it is not expected to harm an unborn baby, it may pass into breast milk and should not be used while nursing.
Prior to beginning treatment with this antihistamine, patients should discuss their other medications and supplements with their doctors. This drug can interact with monoamine oxidase inhibitors (MAOIs), sleeping pills, and anxiety medications. Drugs taken for depression can also interact with it.