The reference site for Clemastine

Clemastine, also known as meclastin, is an antihistamine and anticholinergic.

WHAT IS Clemastine?

Clemastine is an antihistamine. This medicine works by blocking the effects of the naturally occurring chemical histamine in your body.

Clemastine is used to treat sneezing, runny nose, itchy and watery eyes, hives, rashes, itching, and other symptoms of allergies and the common cold.


Brand Name(s): Tavist; Tavist-1; Allerhist-1; Contac 12 Hour Allergy
CAS nº: 17-7-4
(CLEM as teen)


Product Info

The sections below will provide you with more specific information and guidelines related to clemastine and its correct use. Please read them carefully.

FDA Information

Clemastine has been approved by the US Food and Drug Administration and is currently available with a prescription.

Please visit the official site of the FDA for further information.

Why is this medication prescribed?

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 an antihistamine with anticholinergic and sedative effects. Antihistamines competitively bind to histamine receptor sites, thus reducing the neurotransmitter’s effects. Effects of histamine (which are countered by antihistamines) include:

* Increased capillary permeability
* Increased capillary dilatation
* Edema (i.e. swelling)
* Pruritus
* Gastrointestinal/respiratory smooth muscle constriction

Clemastine inhibits both the vasoconstrictor and vasodilator effects of histamine. Depending on the dose, the drug can produce paradoxical effects, including CNS stimulation or depression.

Most antihistamines exhibit some type of anticholinergic activity. Antihistamines act by competitively binding to H1- receptor sites, thus blocking the binding endogenous histamine. Antihistamines do not chemically inactivate or prevent the normal release of histamine.

Clemastine is rapidly absorbed from the gastrointestinal tract and peak plasma concentrations are attained in 2-4 hours.

Mechanism of Action
Clemastine is a selective histamine H1 antagonist. It binds to the histamine H1 receptor, thus blocking the action of endogenous histamine, which leads to temporary relief of the negative symptoms caused by histamine.

Other uses for this medicine

This medication has not been approved for any alternative uses other than those mentioned in the product information section.

Dosage and using this medicine

Clemastine comes in regular and extended-release tablets and liquid to be administered orally. It is usually taken twice a day.

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.

Clemastine can be taken with or without food, and with a full glass of water.

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.

What special precautions should I follow?


Tell your doctor if you are taking any of the following medications: 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.

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.

Also, 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.

Moreover, inform 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.

Additionally, clemastine passes into breast milk. Infants are especially sensitive to the effects of antihistamines, and serious side effects could occur in a nursing 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.

What should I do if I forget a dose?

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.

What side effects can this medication cause?

Stop taking clemastine and seek emergency medical attention if you experience an allergic reaction (such as 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:

sleepiness, fatigue, or dizziness
dry mouth
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.

What storage conditions are needed for this medicine?

Always 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).

Also, remeber to 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 an emergency/overdose

In the case of an overdose, call your local poison control center on 1-800-222-1222. However, if the victim has collapsed or is not breathing, please call the local emergency services immediately on 911.

Symptoms of overdose may include:

extreme sleepiness
confusion, weakness
ringing in the ears
blurred vision
large pupils
dry mouth
possibly seizures

Product Images


Below you will find images and specific information on the principal types of clemastine that exist, including their respective brand name(s), strength, inscription codes, manufacturers and/or distributors.

The information below includes general information and guidelines for patients taking this medication and should never be used to substitute professional medical advice that can be provided by a qualified physician or family doctor.

Name: TAVIST-1®
Strength(s): 1.34 MG
Manufacturer: NOVARTIS

Name: TAVIST-1®
Strength(s): 1.34 MG
Imprint: A-S-H
Manufacturer: NOVARTIS

Strength(s): 1.34 MG
Imprint: TAVIST D
Manufacturer: NOVARTIS

Strength(s): 2.68 MG
Imprint: 93 308
Manufacturer: TEVA USA

Strength(s): 2.68 MG
Imprint: GG 160
Manufacturer: SANDOZ

Strength(s): 0.5 MG / 5 ML
Manufacturer: SILARX

Strength(s): 0.5 MG / 5 ML
Manufacturer: TEVA


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