loratadine
Claritin

Available forms
Available by prescription only
Syrup: 1 mg/ml
Tablets: 10 mg
Tablets (rapidly distintegrating): 10 mg

Indications and dosages
 Symptomatic treatment of seasonal allergic rhinitis, idiopathic chronic urticaria. Adults and children age 6 and older: 10 mg P.O. daily.
Children ages 2 to 5: 5 mg P.O. daily.
≡ Dosage adjustment. For adults and children age 6 and older with liver impairment or glomerular filtration rate below 30 ml/minute, adjust dosage to 10 mg every other day. For children ages 2 to 5 with liver or renal impairment, adjust dosage to 5 mg every other day.
 Perennial allergic rhinitis ◇. Adults: 10 mg P.O. daily.

Pharmacodynamics
Antihistaminic action: Loratadine is a long-acting tricyclic antihistamine with selective peripheral H₁-receptor antagonistic activity.

Pharmacokinetics
Absorption: Readily absorbed. Because loratadine’s peak plasma level may be delayed by 1 hour with a meal, administer drug on an empty stomach.
Distribution: About 97% is bound to plasma protein. Drug doesn’t readily cross the blood-brain barrier.
Metabolism: Extensively metabolized to an active metabolite (descarboethoxyloratadine), primarily by cytochrome P-450 3A4 and, to a lesser extent, by cytochrome P-450 2D6.
Excretion: About 80% of dose is equally excreted via urine and feces. Mean elimination half-life is 8 1/4 hours for loratadine. Drug isn’t eliminated by hemodialysis; it’s unknown whether drug is eliminated by peritoneal dialysis.

Contraindications and precautions
Contraindicated in patients hypersensitive to drug. Use cautiously in patients with hepatic impairment and in breast-feeding women.

Interactions
Drug-drug. Drugs known to inhibit hepatic metabolism: Definitive interaction studies haven’t been completed. Use together cautiously.
Drug-herb. Licorice: May prolong QT interval and be potentially additive. Discourage use together.

Adverse reactions
CNS: headache, somnolence, fatigue.
GI: dry mouth.

Effects on lab test results
None reported.

Overdose and treatment
Somnolence, tachycardia, and headache have been reported with overdoses of 40 to 180 mg. If overdose occurs, institute symptomatic and supportive measures promptly and maintain for as long as needed.
 Treatment consists of emesis with ipecac syrup, except in patients with impaired consciousness, followed by administration of activated charcoal to adsorb any remaining drug. If patient doesn’t vomit or vomiting is contraindicated, perform gastric lavage with normal saline solution. Saline cathartics also may be of value for rapid dilution of bowel contents.

Special considerations
• No information exists to indicate that drug abuse or dependency occurs.
• Store drug in a cool, dry place away from heat and direct sunlight.
Breast-feeding patients
• Loratadine appears in breast milk. Antihistamine therapy is contraindicated in breast-feeding women.
Pediatric patients
• Safety and efficacy in children younger than age 2 haven’t been established.

Patient education
• Tell patient to take drug only once daily. Tell him to call if symptoms persist or worsen.
• Warn patient to stop taking drug 4 days before allergy skin tests to preserve accuracy of tests.

Reactions may be common, uncommon, life-threatening, or COMMON AND LIFE THREATENING.
◆ Canada only
◇ Unlabeled clinical use