CLEMASTINE FUMARATE- clemastine fumarate tablet
Sandoz Inc
Rx only
DESCRIPTION
Clemastine fumarate belongs to the benzhydryl ether group of antihistaminic compounds. The chemical name is (+)-2-[-2- [(p-chloro-?-methyl-?-phenylbenzyl) oxy] ethyl]-1-methylpyrrolidine hydrogen fumarate. It has the following structural formula:
Clemastine fumarate structural formula
(click image for full-size original)
Each tablet for oral administration contains 2.68 mg clemastine fumarate. Inactive ingredients include lactose (monohydrate), hydroxypropyl methylcellulose, magnesium stearate, microcrystalline cellulose, sodium starch glycolate, and starch (corn).
CLINICAL PHARMACOLOGY
Clemastine fumarate is an antihistamine with anticholinergic (drying) and sedative side effects. Antihistamines appear to compete with histamine for cell receptor sites on effector cells. The inherently long duration of antihistaminic effects of clemastine has been demonstrated in wheal and flare studies. In normal human subjects who received histamine injections over a 24-hour period, the antihistaminic activity of clemastine reached a peak at 5 to 7 hours, persisted for 10 to 12 hours and, in some cases, for as long as 24 hours. Pharmacokinetic studies in man utilizing 3 H and 14 C labeled compound demonstrates that: clemastine is rapidly and nearly completely absorbed from the gastrointestinal tract, peak plasma concentrations are attained in 2 to 4 hours, and urinary excretion is the major mode of elimination.
INDICATIONS AND USAGE
Clemastine fumarate tablets are indicated for the relief of symptoms associated with allergic rhinitis such as sneezing, rhinorrhea, pruritus, and lacrimation.
Clemastine fumarate tablets are also indicated for the relief of mild, uncomplicated allergic skin manifestations of urticaria and angioedema.
It should be noted that clemastine is indicated for the dermatologic indications at the 2.68 mg dosage level only.
CONTRAINDICATIONS
Use in Nursing Mothers
Because of the higher risk of antihistamines for infants generally and for newborns and prematures in particular, antihistamine therapy is contraindicated in nursing mothers.
Use in Lower Respiratory Disease
Antihistamines should not be used to treat lower respiratory tract symptoms including asthma.
Antihistamines are also contraindicated in the following conditions:
Hypersensitivity to clemastine fumarate or other antihistamines of similar chemical structure.
Monoamine oxidase inhibitor therapy (see Drug Interaction Section).
WARNINGS
Antihistamines should be used with considerable caution in patients with: narrow angle glaucoma, stenosing peptic ulcer, pyloroduodenal obstruction, symptomatic prostatic hypertrophy, and bladder neck obstruction.
Use in Children
Safety and efficacy of clemastine fumarate have not been established in children under the age of 12 years.
Use in Pregnancy
Experience with this drug in pregnant women is inadequate to determine whether there exists a potential for harm to the developing fetus.
Use with CNS Depressants
Clemastine has additive effects with alcohol and other CNS depressants (hypnotics, sedatives, tranquilizers, etc.)
Use in Activities Requiring Mental Alertness
Patients should be warned about engaging in activities requiring mental alertness such as driving a car or operating appliances, machinery, etc.
Use in the Elderly (approximately 60 years or older)
Antihistamines are more likely to cause dizziness, sedation, and hypotension in elderly patients.