What is/are Clemastine Tablets?
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 providers 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 with a full glass of water. Follow the directions on the prescription label. Take your medicine at regular intervals. Do not take your medicine 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 12 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 if I miss a dose?
If you miss a dose, take it as soon as you can. If it is almost time for your next dose, take only that dose. Do not take double or extra doses.
What may interact with this medicine?
Do not take this medicine with any of the following:
MAOIs like Carbex, Eldepryl, Marplan, Nardil, and Parnate
This medicine may also interact with the following:
alcohol barbiturates like phenobarbital medicines for depression, anxiety, or psychotic disturbances medicines for sleep muscle relaxers narcotic pain medicines other medicines for cold, cough or allergy
This list may not describe all possible interactions. Give your health care providers 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 side effects may I notice from 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 changes in vision confused, agitated, nervous fast, irregular heartbeat low blood pressure seizures tremor trouble breathing trouble passing urine uncoordinated 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, diarrhea drowsy, tired dry mouth, nose, throat headache loss of appetite stomach upset, vomiting thick mucous unusual sweating
This list may not describe all possible side effects.
What should I watch for while using this medicine?
Visit your doctor or health care professional for regular check ups. Tell your doctor if your symptoms do not improve 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.
Where should I keep this 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.
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 (Itch)
- 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 does also act as FIASMA (functional inhibitor of acid sphingomyelinase).
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..
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.
Clemastine is indicated for use in treating allergic rhinitis, such as sneezing, rhinorrhea, pruritus and lacrimation.
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.
This article uses material from the Wikipedia article Clemastine, which is released under the Creative Commons Attribution-Share-Alike License 3.0.