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Clemastine

 
Drug Info: Clemastine

Brand names: Allerhist-1®, Anti-Hist® 1, Antihist®-1, Contac® 12 Hour Allergy, Dailyhist®-1, Dayhist-1®, Equate® Dayhist Allergy, Tavist®, Tavist® Allergy, Wal-Hist™ Allergy

Chemical formula:



Clemastine Fumarate Oral syrup

What is this medicine?

CLEMASTINE is an antihistamine. It is used to treat the symptoms of allergies and mild allergic reactions. This medicine will not treat an infection.

This medicine may be used for other purposes; ask your health care provider or pharmacist if you have questions.

What should I tell my health care provider before I take this medicine?

They need to know if you have any of these conditions:
• glaucoma
• high blood pressure or heart disease
• if you have taken an MAOI like Carbex, Eldepryl, Marplan, Nardil, or Parnate in last 14 days
• lung or breathing disease, like asthma
• pain or trouble passing urine
• stomach problems
• an unusual or allergic reaction to clemastine, other medicines foods, dyes, or preservatives
• pregnant or trying to get pregnant
• breast-feeding

How should I use this medicine?

Take this medicine by mouth. Follow the directions on the prescription label. Use a specially marked spoon or container to measure each dose. Ask your pharmacist if you do not have one. Household spoons are not accurate. Take your medicine at regular intervals. Do not take it more often than directed.

Talk to your pediatrician regarding the use of this medicine in children. While this drug may be prescribed for children as young as 6 years old for selected conditions, precautions do apply.

Patients over 60 years old may have a stronger reaction and need a smaller dose.

Overdosage: If you think you have taken too much of this medicine contact a poison control center or emergency room at once.
NOTE: This medicine is only for you. Do not share this medicine with others.

What may interact with this medicine?

Do not take this medicine with any of the following medications:
• MAOIs like Carbex, Eldepryl, Marplan, Nardil, and Parnate

This medicine may also interact with the following medications:
• alcohol
• barbiturates like phenobarbital
• medicines for depression, anxiety, or psychotic disturbances
• medicines for sleep
• muscle relaxers
• narcotic medicines for pain
• other medicines for cold, cough, or allergy

This list may not describe all possible interactions. Give your health care provider a list of all the medicines, herbs, non-prescription drugs, or dietary supplements you use. Also tell them if you smoke, drink alcohol, or use illegal drugs. Some items may interact with your medicine.

What should I watch for while using this medicine?

Visit your doctor or health care professional for regular check ups. Tell your doctor or health care professional if your symptoms do not start to get better or if they get worse.

You may get drowsy or dizzy. Do not drive, use machinery, or do anything that needs mental alertness until you know how this medicine affects you. Do not stand or sit up quickly, especially if you are an older patient. This reduces the risk of dizzy or fainting spells. Alcohol may interfere with the effect of this medicine. Avoid alcoholic drinks.

Your mouth may get dry. Chewing sugarless gum or sucking hard candy, and drinking plenty of water may help. Contact your doctor if the problem does not go away or is severe.

This medicine may cause dry eyes and blurred vision. If you wear contact lenses you may feel some discomfort. Lubricating drops may help. See your eye doctor if the problem does not go away or is severe.

This medicine can make you more sensitive to the sun. Keep out of the sun. If you cannot avoid being in the sun, wear protective clothing and use sunscreen. Do not use sun lamps or tanning beds/booths.

What side effects may I notice from receiving this medicine?

Side effects that you should report to your doctor or health care professional as soon as possible:
• allergic reactions like skin rash, itching or hives, swelling of the face, lips, or tongue
• breathing problems
• changes in vision
• confused, agitated, or nervous
• fast, irregular heartbeat
• low blood pressure
• seizures
• tremor
• trouble passing urine or change in the amount of urine
• trouble walking, dizziness, loss of balance or coordination
• unusually weak or tired

Side effects that usually do not require medical attention (report to your doctor or health care professional if they continue or are bothersome):
• constipation or diarrhea
• dry mouth, nose, or throat
• headache
• loss of appetite
• stomach upset, vomiting
• thick mucous
• unusual sweating

This list may not describe all possible side effects. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Where should I keep my medicine?

Keep out of the reach of children.

Store at room temperature, between 15 and 25 degrees C (59 and 77 degrees F). Keep away from heat and light. Throw away any unused medicine after the expiration date.

Last updated: 7/1/2002

Important Disclaimer: The drug information provided here is for educational purposes only. It is intended to supplement, not substitute for, the diagnosis, treatment and advice of a medical professional. This drug information does not cover all possible uses, precautions, side effects and interactions. It should not be construed to indicate that this or any drug is safe for you. Consult your medical professional for guidance before using any prescription or over the counter drugs.

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Wikipedia: Clemastine
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Clemastine
Systematic (IUPAC) name
(2R)-2-{2-[(1R)-1-(4-chlorophenyl)-1-phenylethoxy]ethyl}-1-methylpyrrolidine
Identifiers
CAS number 17-7-4
ATC code R06AA04
PubChem 2781
DrugBank APRD00875
Chemical data
Formula C21H26ClNO 
Mol. mass 343.9
Pharmacokinetic data
Bioavailability 39.2%
Metabolism Hepatic
Half life 21.3 Hours
Excretion Renal
Therapeutic considerations
Pregnancy cat.

B (USA)

Legal status

Unscheduled;
OTC

Routes Oral

Clemastine, also known as meclastin, is an antihistamine drug. Unlike loratadine or fexofenadine, clemastine is a sedating antihistamine, however it exhibits fewer side effects than most of the widely used antihistamines. Clemastine is also classified as an antipruritic (i.e. it stops itching).

Contents

Pharmacology

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.

Metabolism

Antihistamines are thought to be metabolized in the liver, mostly by mono-/didemethylation and glucuronide conjugation. It is an inhibitor of cytochrome P450 2D6 and may interfere with other drugs metabolized by this isozyme.

Indications

Clemastine is indicated for use in treating allergic rhinitis, such as sneezing, rhinorrhea, pruritus and lacrimation.

Availability

Clemastine is an OTC drug, and is available as a syrup (0.5 mg per 5mL) and tablet (1mg). It is sold in the United States under the brand name Tavist.

Brand Names in other countries

Brasil - In Brasil it is sold under the brand name of Agasten by Novartis.

Germany - In Germany sold under the brand name Tavegil.

Sweden - In Sweden it is sold under the brand name of Tavegyl and unlike the newer non-sedative antihistamines used for allergy, prescription only.

Toxicity

Overdosage symptoms are paradoxical, ranging from CNS depression to stimulation. Stimulation is most common in children, and is usually followed by excitement, hallucinations, ataxia, incoordination, muscle twitching, athetosis, hyperthermia, cyanosis convulsions, tremors, and hyperreflexia. This may be followed by postictal depression and cardiovascular/respiratory arrest. Other common overdose symptoms include dry mouth, fixed dilated pupils, flushing of the face, and pyrexia. In adults, overdose usually leads to CNS depression, ranging from drowsiness to coma.

The oral LD50 of clemastine in the rat and mouse is 3550 mg/kg and 730 mg/kg, respectively.

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Drug Info. Gold Standard. Copyright © 2008 by Gold Standard. All rights reserved.  Read more
Wikipedia. This article is licensed under the Creative Commons Attribution/Share-Alike License. It uses material from the Wikipedia article "Clemastine" Read more