Pronunciation:

(KLEM as teen)

U.S. Brand Names:

Synonyms:

Generic Available:

Use:

Pregnancy Risk Factor:

Lactation:

Contraindications:

Warnings/Precautions:

Adverse Reactions:

Cardiovascular: Palpitations, hypotension, tachycardia

Central nervous system: Dyscoordination, sedation, slight to moderate somnolence, sleepiness, confusion, restlessness, nervousness, insomnia, irritability, fatigue, headache, increased dizziness

Dermatologic: Rash, photosensitivity

Gastrointestinal: Diarrhea, nausea, xerostomia, epigastric distress, vomiting, constipation

Genitourinary: Urinary frequency, difficult urination, urinary retention

Hematologic: Hemolytic anemia, thrombocytopenia, agranulocytosis

Ocular: Blurred vision

Otic: Tinnitus

Respiratory: Thickening of bronchial secretions

Miscellaneous: Anaphylaxis

Overdosage/Toxicology:

Symptoms of overdose include anemia, metabolic acidosis, hypotension, hypothermia

There is no specific treatment for an antihistamine overdose, however, most of its clinical toxicity is due to anticholinergic effects. For anticholinergic overdose with severe life-threatening symptoms, physostigmine 1-2 mg (0.5 mg or 0.02 mg/kg for children) I.V., slowly may be given to reverse these effects.

Drug Interactions:

Increased toxicity (CNS depression): CNS depressants, MAO inhibitors, tricyclic antidepressants, phenothiazines

Ethanol/Nutrition/Herb Interactions:

Mechanism of Action:

Pharmacodynamics/Kinetics:

Onset of action: Peak effect: Therapeutic: 5-7 hours

Duration: 8-16 hours

Absorption: Almost complete

Metabolism: Hepatic

Excretion: Urine

Dosage:

Infants and Children <6 years: 0.05 mg/kg/day as clemastine base or 0.335-0.67 mg/day clemastine fumarate (0.25-0.5 mg base/day) divided into 2 or 3 doses; maximum daily dosage: 1.34 mg (1 mg base)

Children 6-12 years: 0.67-1.34 mg clemastine fumarate (0.5-1 mg base) twice daily; do not exceed 4.02 mg/day (3 mg/day base)

Children 12 years and Adults:

1.34 mg clemastine fumarate (1 mg base) twice daily to 2.68 mg (2 mg base) 3 times/day; do not exceed 8.04 mg/day (6 mg base)

OTC labeling: 1.34 mg clemastine fumarate (1 mg base) twice daily; do not exceed 2 mg base/24 hours

Elderly: Lower doses should be considered in patients >60 years

Monitoring Parameters:

Patient Education:

Nursing Implications:

Dental Health: Effects on Dental Treatment:

Dental Health: Vasoconstrictor/Local Anesthetic Precautions:

Mental Health: Effects on Mental Status:

Mental Health: Effects on Psychiatric Treatment:

Dosage Forms:

Syrup, as fumarate [prescription formulation]: 0.67 mg/5 mL (120 mL) [0.5 mg base/5 mL; contains alcohol 5.5%; citrus flavor]

Tablet, as fumarate: 1.34 mg [1 mg base; OTC], 2.68 mg [2 mg base; prescription formulation]

Dayhist® Allergy, Tavist® Allergy: 1.34 mg [1 mg base]

International Brand Names: