CLARITIN HIVES RELIEF
Clinical safety rating: caution
Comprehensive clinical and safety monograph for CLARITIN HIVES RELIEF (CLARITIN HIVES RELIEF).
Selective inverse agonist at histamine H1 receptors, blocking histamine-mediated effects in allergic reactions.
| Metabolism | Primarily hepatic via CYP3A4 and CYP2D6; forms active metabolite desloratadine. |
| Excretion | Renal: ~40% as metabolites, <1% unchanged; Fecal: ~40%; Biliary: minor contribution. |
| Half-life | 8.4 hours (range 3-20 hours) for loratadine; 28 hours (range 8.8-92 hours) for active metabolite desloratadine, allowing once-daily dosing. |
| Protein binding | Loratadine: 97-99% to albumin and alpha-1-acid glycoprotein; desloratadine: 73-76%. |
| Volume of Distribution | Loratadine: 120 L/kg, indicating extensive tissue distribution; desloratadine: 40 L/kg. |
| Bioavailability | Oral: ~100% (loratadine is rapidly and well absorbed; first-pass metabolism to desloratadine reduces parent drug concentration but active metabolite contributes to effect). |
| Onset of Action | Oral: 1-3 hours after ingestion. |
| Duration of Action | 24 hours, supporting once-daily dosing for allergic rhinitis and urticaria. |
| Molecular Weight | 382.88 |
10 mg orally once daily
| Dosage form | TABLET |
| Renal impairment | GFR 30-89 mL/min: no adjustment; GFR <30 mL/min: 5 mg orally once daily |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B or C: 5 mg orally once daily |
| Pediatric use | 6-11 years: 5 mg orally once daily; 12 years and older: 10 mg orally once daily |
| Geriatric use | No specific adjustment; use caution due to age-related renal impairment may require 5 mg once daily |
| 1st trimester | No adequate well-controlled studies in pregnant women. Animal studies have shown no evidence of harm. Use only if clearly needed. |
| 2nd trimester | No known risk in second trimester; consider maternal benefit vs fetal risk. |
| 3rd trimester | No known risk in third trimester; consider maternal benefit vs fetal risk. |
Clinical note
Comprehensive clinical and safety monograph for CLARITIN HIVES RELIEF (CLARITIN HIVES RELIEF).
| Placental transfer | Loratadine crosses the placenta; fetal plasma levels are approximately 50-80% of maternal levels. |
| Breastfeeding | Loratadine is excreted into breast milk in small amounts (estimated 1.1% of maternal dose). Peak milk concentration occurs about 1-2 hours after dose. No adverse effects reported in breastfed infants. Caution in preterm infants or those with compromised hepatic function. |
■ FDA Black Box Warning
None.
| Serious Effects |
Hypersensitivity to loratadine or any component of the formulation
| Precautions | Caution in patients with hepatic or renal impairment; avoid use with alcohol or CNS depressants; may cause drowsiness or dizziness; use with caution in elderly patients. |
| Food/Dietary | No significant food interactions; grapefruit juice does not affect loratadine metabolism. Avoid alcohol as it may potentiate CNS depression. |
| Clinical Pearls | Loratadine is a second-generation antihistamine with minimal anticholinergic effects; onset of action within 1-3 hours, duration 24 hours; not effective for acute urticaria in some patients; may require dose adjustment in hepatic impairment (Child-Pugh class B or C). |
Loading safety data…
| Lactation Rating | L1 (Safe) |
| Teratogenic Risk | Loratadine is categorized as FDA Pregnancy Category B. Animal studies have not demonstrated fetal harm, but adequate, well-controlled studies in pregnant women are lacking. No known teratogenic risk in any trimester; however, first-trimester exposure should be with caution. |
| Fetal Monitoring | No specific fetal monitoring required. Standard prenatal care with assessment of fetal growth and development is sufficient. Monitor maternal blood pressure and heart rate if high doses used. |
| Fertility Effects | No known adverse effects on fertility in animal studies. No human data suggest impairment of male or female reproductive function. |
| Patient Advice | Take once daily with or without food. · Do not exceed recommended dose; may cause drowsiness in some individuals. · Avoid alcohol as it may increase drowsiness. · If symptoms persist after 3 days, consult a healthcare provider. · Not recommended for children under 6 years without medical advice. |