What is clemastine?
Clemastine is an antihistamine. Clemastine blocks the effects of the naturally occurring
chemical histamine in your body.
Clemastine is used to treat sneezing, runny nose, itching watery eyes, hives, rashes,
itching, and other symptoms of allergies and the common cold.
Clemastine is may also be used for purposes other than those listed in this medication
guide.
What should I discuss with my healthcare provider before taking clemastine?
Do not take clemastine if you have taken a monoamine oxidase inhibitor (MAOI)
such as isocarboxazid (Marplan), phenelzine (Nardil), or tranylcypromine (Parnate) in the last 14
days. A very dangerous drug interaction could occur, leading to serious side effects.
Before taking this medication, tell your doctor if you have
-
glaucoma or increased pressure in the eye;
-
a stomach ulcer;
-
an enlarged prostate, bladder problems, or difficulty
urinating;
-
an overactive thyroid (hyperthyroidism);
-
hypertension or any type of heart problems; or
-
asthma.
You may not be able to take clemastine, or you may require a lower
dose or special monitoring during treatment if you have any of the conditions listed above.
Clemastine is in the FDA pregnancy category B. This means that it is unlikely to
harm an unborn baby. Do not take clemastine without first talking to your doctor if you are
pregnant.
Clemastine passes into breast milk. Infants are especially sensitive to the effects of
antihistamines, and serious side effects could occur in a nursing baby. Clemastine is not
recommended if you are breast-feeding a baby. Do not take clemastine without first talking to
your doctor if you are nursing a baby.
If you are over 60 years of age, you may be more likely to experience side effects
from clemastine. You may require a lower dose of this medication.
How should I take clemastine?
Take clemastine exactly as directed by your doctor. If you do not understand these
directions, ask your pharmacist, nurse, or doctor to explain them to you.
Take each dose with a full glass of water.
Clemastine can be taken with or without food.
To ensure that you get a correct dose, measure the syrup form of clemastine with a special
dose-measuring spoon or cup, not with a regular tablespoon. If you do not have a dose-measuring
device, ask your pharmacist where you can get one.
Never take more of this medication than is prescribed for you. The maximum amount of
clemastine that you should take in 1 day is 8.04 mg.
Store clemastine at room temperature away from moisture and heat.
What happens if I miss a dose of clemastine?
Take the missed dose as soon as you remember. However, if it is almost time for your
next dose, skip the missed dose and take only your next regularly scheduled dose.
Do
not
take a double dose of this medication unless otherwise directed by your doctor.
Where can I get more information about clemastine?
Your pharmacist has information about clemastine written for health professionals that you may read.
What are the possible side effects of clemastine?
Stop taking clemastine and seek emergency medical attention if you experience an
allergic reaction (difficulty breathing; closing of your throat; swelling of your lips, tongue, or
face; or hives).
Other, less serious side effects may be more likely to occur. Continue to take clemastine
and talk to your doctor if you experience
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sleepiness, fatigue, or dizziness;
-
headache;
-
dry mouth; or
-
difficulty urinating or an enlarged prostate.
Side effects other than those listed here may also occur. Talk to your
doctor about any side effect that seems unusual or that is especially bothersome. You may report side effects to FDA at 1-800-FDA-1088.
What is the most important information I should know about clemastine?
Use caution when driving, operating machinery, or performing other hazardous
activities. Clemastine may cause dizziness or drowsiness. If you experience dizziness or
drowsiness, avoid these activities.
Use alcohol cautiously. Alcohol may increase drowsiness and dizziness while you are
taking clemastine.
What should I avoid while taking clemastine?
Use caution when driving, operating machinery, or performing other hazardous
activities. Clemastine may cause dizziness or drowsiness. If you experience dizziness or
drowsiness, avoid these activities.
Use alcohol cautiously. Alcohol may increase drowsiness and dizziness while you are
taking clemastine.
What other drugs will affect clemastine?
Do not take clemastine if you have taken a monoamine oxidase inhibitor (MAOI)
such as isocarboxazid (Marplan), phenelzine (Nardil), or tranylcypromine (Parnate) in the last 14
days. A very dangerous drug interaction could occur, leading to serious side effects.
Talk to your pharmacist before taking other over-the-counter cough, cold, allergy, or
insomnia medications. These may contain medicines similar to clemastine, which could lead to
an overdose of antihistamine.
Before taking this medication, tell your doctor if you are taking any of the following
medicines:
-
anxiety or sleep medicines such as alprazolam (Xanax), diazepam
(Valium), chlordiazepoxide (Librium), temazepam (Restoril), or triazolam (Halcion);
-
medications for depression such as amitriptyline (Elavil),
doxepin (Sinequan), nortriptyline (Pamelor), fluoxetine (Prozac), sertraline (Zoloft), or
paroxetine (Paxil); or
-
any other medications that make you feel drowsy, sleepy, or
relaxed.
Drugs other than those listed here may also interact with clemastine.
Talk to your doctor and pharmacist before taking any prescription or over-the-counter medicines.
What happens if I have an overdose of clemastine?