CLARITIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for CLARITIN (CLARITIN).
Loratadine is a long-acting tricyclic antihistamine with selective peripheral H1 receptor antagonistic activity. It inhibits histamine release from mast cells and reduces allergic responses.
| Metabolism | Extensively metabolized in the liver via CYP3A4 and CYP2D6 to its active metabolite desloratadine. Also undergoes minor metabolism by other pathways. |
| Excretion | Renal 40% as metabolites, fecal 40% as metabolites, biliary <5% as unchanged drug |
| Half-life | Terminal elimination half-life 27 hours (range 22-30 hours); clinical context: allows once-daily dosing, steady state reached in 5-7 days |
| Protein binding | 97-99% bound to albumin and alpha-1-acid glycoprotein |
| Volume of Distribution | 11.2 L/kg (range 6.2-14.1 L/kg); clinical meaning: extensive tissue distribution with high peripheral binding |
| Bioavailability | Oral: 100% (tablet and syrup), 70% (orally disintegrating tablet due to first-pass metabolism) |
| Onset of Action | Oral: 1-3 hours for symptom relief; intranasal: 30 minutes for nasal congestion; ophthalmic: 1 hour for ocular itching |
| Duration of Action | 24 hours with regular dosing; clinical note: single dose provides symptom relief for 24 hours due to long half-life, but may take 2-3 days for maximal effect in chronic urticaria |
| Molecular Weight | 382.88 |
10 mg orally once daily for adults and children ≥6 years.
| Dosage form | CAPSULE |
| Renal impairment | For GFR <30 mL/min: 10 mg every 48 hours. No adjustment for GFR ≥30 mL/min. |
| Liver impairment | For Child-Pugh class B or C: 10 mg every 48 hours. No adjustment for Child-Pugh class A. |
| Pediatric use | Children 6-11 years: 10 mg orally once daily. Children 2-5 years: 5 mg orally once daily. Children <2 years: safety and efficacy not established. |
| Geriatric use | No specific dose adjustment required; however, elderly patients may have decreased renal function; consider renal dosing if GFR <30 mL/min. |
| 1st trimester | Limited human data; animal studies show no evidence of teratogenicity. Use only if clearly needed. |
| 2nd trimester | No known increased risk of malformations; generally considered low risk. |
| 3rd trimester | Avoid use near term due to potential for neonatal withdrawal or sedation. |
Clinical note
Comprehensive clinical and safety monograph for CLARITIN (CLARITIN).
| Placental transfer | Loratadine crosses the placenta; fetal serum concentrations are approximately 20% of maternal levels. |
| Breastfeeding | Loratadine and its active metabolite desloratadine are excreted into breast milk in low amounts; unlikely to cause adverse effects in nursing infants. Consider alternative antihistamines with more data, such as cetirizine. |
| Lactation Rating |
■ FDA Black Box Warning
None
| Serious Effects |
Hypersensitivity to loratadine or any component of the formulation
| Precautions | Risk of severe allergic reactions (anaphylaxis, angioedema), Use with caution in patients with severe hepatic impairment (dose adjustment recommended), Avoid concurrent use with other antihistamines or CNS depressants, May cause drowsiness in some individuals (less than other antihistamines), Use with caution in patients with renal impairment (creatinine clearance <30 mL/min: dose adjustment recommended) |
| Food/Dietary | No significant food interactions. Grapefruit juice may slightly increase absorption but not clinically relevant. |
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| L2 (Safer) |
| Teratogenic Risk | Loratadine (CLARITIN) is classified as FDA Pregnancy Category B. Animal studies have not demonstrated teratogenic effects; however, no adequate and well-controlled studies exist in pregnant women. First trimester: Insufficient data to define risk; second and third trimester: No known fetal risks from limited human data. |
| Fetal Monitoring | No specific monitoring required beyond routine prenatal care. Observe for any signs of sedation or irritability in the neonate if used near term. |
| Fertility Effects | Loratadine has no known adverse effects on fertility in animal studies. Human data are lacking; however, it is not expected to impact fertility. |
| Clinical Pearls |
| Claritin (loratadine) is a long-acting, non-sedating antihistamine. Onset within 1-3 hours, duration 24 hours. Not effective for nasal congestion. Caution in severe hepatic impairment (dose reduction or alternative). Does not cause QTc prolongation significantly. Can be used with pseudoephedrine for congestion. |
| Patient Advice | Take once daily as directed; do not exceed recommended dose. · May take with or without food. · Avoid alcohol as it may increase drowsiness. · Notify doctor if pregnant or breastfeeding. · Store at room temperature away from moisture and heat. |