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.
Dosage and using this medicine
What special precautions should I follow?
What should I do if I forget a dose?
What side effects can this medication cause?