CLARINEX D 24 HOUR
Clinical safety rating: caution
Comprehensive clinical and safety monograph for CLARINEX D 24 HOUR (CLARINEX D 24 HOUR).
Desloratadine is a long-acting tricyclic histamine antagonist with selective peripheral H1-receptor antagonist activity. Loratadine is a long-acting antihistamine that selectively antagonizes peripheral H1-receptors.
| Metabolism | Desloratadine: primarily metabolized by CYP3A4 and CYP2D6. Loratadine: extensively metabolized by CYP3A4 and CYP2D6 to active metabolite desloratadine. |
| Excretion | Desloratadine: ~87% excreted as metabolites (41% urine, 43% feces), <2% unchanged. Pseudoephedrine: ~70-90% excreted unchanged in urine. |
| Half-life | Desloratadine: terminal t1/2 27 hours (range 20-50h) supporting once-daily dosing. Pseudoephedrine: t1/2 5-8 hours (up to 16h in alkaline urine). |
| Protein binding | Desloratadine: 85% bound (mainly albumin). Pseudoephedrine: weakly bound (<20% to plasma proteins). |
| Volume of Distribution | Desloratadine: Vd ~36-120 L/kg (extensive tissue distribution). Pseudoephedrine: Vd ~2.5-3.5 L/kg. |
| Bioavailability | Desloratadine: oral bioavailability not well defined due to extensive first-pass metabolism; estimated ~40-60%. Pseudoephedrine: oral bioavailability ~100%. |
| Onset of Action | Desloratadine: 1 hour for histamine-induced wheal suppression. Pseudoephedrine: 15-30 minutes for nasal decongestion. |
| Duration of Action | Desloratadine: 24 hours (once daily). Pseudoephedrine: 12-24 hours due to extended-release formulation; full 24-hour effect requires intact tablet. |
1 tablet (5 mg desloratadine/120 mg pseudoephedrine) orally once daily
| Dosage form | TABLET, EXTENDED RELEASE |
| Renal impairment | Contraindicated if GFR < 30 mL/min. For GFR 30-50 mL/min: maximum dose 1 tablet every 48 hours. |
| Liver impairment | Contraindicated in severe hepatic impairment (Child-Pugh class C). For Child-Pugh class A or B: no dosage adjustment required. |
| Pediatric use | Not recommended in children < 12 years. For children ≥12 years: same as adult dose (1 tablet once daily). |
| Geriatric use | Use with caution in elderly patients due to increased risk of dizziness, anticholinergic effects, and hypertension. Consider alternative therapies; if used, start at lower doses and monitor closely. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for CLARINEX D 24 HOUR (CLARINEX D 24 HOUR).
| Breastfeeding | Desloratadine and pseudoephedrine are excreted in breast milk. Pseudoephedrine M/P ratio ~3.3; may reduce milk production and cause irritability in infants. Avoid use in breastfeeding due to pseudoephedrine component. |
| Teratogenic Risk | FDA Pregnancy Category C. Desloratadine has shown no teratogenic effects in animal studies; pseudoephedrine has been associated with increased risk of gastroschisis and hemangiomas in first trimester exposure. Avoid use in first trimester due to pseudoephedrine component. Second and third trimester: risk of pseudoephedrine-induced uterine vasoconstriction and fetal hypoxia. |
■ FDA Black Box Warning
None
| Serious Effects |
["Hypersensitivity to desloratadine, loratadine, or any component","Patients with narrow-angle glaucoma (pseudoephedrine component)","Patients with urinary retention (pseudoephedrine component)","Patients with severe hypertension or severe coronary artery disease (pseudoephedrine component)","Concurrent use of MAO inhibitors or within 14 days of discontinuation"]
| Precautions | ["Caution in patients with severe renal impairment","Caution in patients with hepatic impairment","Caution in patients with cardiovascular disease, especially hypertension and coronary artery disease (pseudoephedrine component)","Avoid use with MAO inhibitors or within 14 days of stopping them (pseudoephedrine component)","May cause drowsiness or dizziness","Do not exceed recommended dose"] |
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| Fetal Monitoring | Monitor fetal heart rate and uterine activity due to pseudoephedrine's sympathomimetic effects. Assess maternal blood pressure and heart rate for hypertension or tachycardia. Ultrasound for fetal growth if used long-term. |
| Fertility Effects | Desloratadine: no reported effect on fertility. Pseudoephedrine: no known adverse effect on fertility in humans; theoretical risk due to vasoconstriction of reproductive organs. |