Why is this medication prescribed?
Clemastine is used to relieve hay fever and allergy symptoms, including sneezing; runny nose; and red, itchy, tearing eyes. Prescription strength clemastine is also used to relieve the itching and swelling of hives. Clemastine helps control symptoms of allergies and colds but does not treat the cause of these symptoms or speed recovery. Clemastine is in a class of medications called antihistamines. It works by blocking the action of histamine, a substance in the body that causes allergic symptoms.
How should this medicine be used?
Clemastine comes as a tablet and a liquid to take by mouth. It is usually taken two or three times a day. Follow the directions on your prescription label or package label carefully, and ask your doctor or pharmacist to explain any part you do not understand. 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.
Other uses for this medicine
This medication is sometimes prescribed for other uses; ask your doctor or pharmacist for more information.
What special precautions should I follow?
Before taking clemastine,
- tell your doctor and pharmacist if you are allergic to clemastine, other antihistamine medications, any other medications, or any of the ingredients in clemastine tablets or liquid. Ask your doctor or pharmacist or check the package label for a list of the ingredients.
- tell your doctor if you are taking monoamine oxidase (MAO) inhibitors such as isocarboxazid (Marplan), phenelzine (Nardil), selegiline (Eldepryl, Emsam, Zelapar), and tranylcypromine (Parnate). Your doctor may tell you not to take clemastine if you are taking one of these medications.
- 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. Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
- tell your doctor if you have or have ever had asthma or lung disease; glaucoma (a condition in which increased pressure in the eye can lead to gradual loss of vision); ulcers; difficulty urinating (due to an enlarged prostate gland); blockage in the passage between the stomach and intestine; blockage in the bladder;heart disease; high blood pressure; seizures; or an overactive thyroid gland.
- tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking clemastine, call your doctor.
- if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking clemastine.
- you should know that this medication may make you drowsy. Do not drive a car or operate machinery until you know how this medication affects you.
- talk to your doctor about the safe use of alcohol while you are taking clemastine. Alcohol can make the side effects of this medication worse.
What special dietary instructions should I follow?
Unless your doctor tells you otherwise, continue your normal diet.
What should I do if I forget a dose?
This medication is usually taken as needed. If your doctor has told you to take clemastine regularly, take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.
What side effects can this medication cause?
Clemastine may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:
- dry mouth, nose, and throat
- decreased coordination
- chest congestion
- excitement (especially in children)
Some side effects can be serious. If you experience any of the following symptoms, call your doctor immediately:
- difficulty urinating
- changes in vision
- fast, pounding, or irregular heartbeat
- difficulty breathing or swallowing
Clemastine may cause other side effects. Call your doctor if you experience any unusual problems while you are taking this medication.
If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online [at http://www.fda.gov/Safety/MedWatch] or by phone [1-800-332-1088].
What should I know about storage and disposal of this medication?
Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom). Throw away any medication that is outdated or no longer needed. Talk to your pharmacist about the proper disposal of your medication.
In case of emergency/overdose
In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.
What other information should I know?
Ask your pharmacist any questions you have about clemastine.
It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.
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