CLARITIN-D 24 HOUR
Clinical safety rating: caution
Comprehensive clinical and safety monograph for CLARITIN-D 24 HOUR (CLARITIN-D 24 HOUR).
Loratadine is a long-acting tricyclic antihistamine with selective peripheral H1-receptor antagonism; pseudoephedrine is a sympathomimetic amine that acts as an alpha-adrenergic agonist, causing vasoconstriction in the nasal mucosa.
| Metabolism | Loratadine: extensively metabolized by CYP3A4 and CYP2D6 to active metabolite desloratadine; pseudoephedrine: partially metabolized in liver by N-demethylation. |
| Excretion | Renal (40%) as unchanged drug and metabolites; biliary/fecal (minor). Approximately 27% of loratadine and 40% of desloratadine are excreted in urine over 10 days. |
| Half-life | Loratadine: 8-11 hours (mean 10.6 ± 4.6 h); desloratadine: 17-24 hours (mean 19.4 ± 7.5 h). Terminal half-life is prolonged in chronic hepatic impairment (mean 37 h for loratadine, 47 h for desloratadine). |
| Protein binding | Loratadine: 97-99% bound to plasma proteins (mainly albumin and α1-acid glycoprotein); desloratadine: 73-76% bound. |
| Volume of Distribution | Loratadine: 119 L/kg (apparent Vd/F ~1000 L). High Vd indicates extensive tissue distribution. Desloratadine: 148 L/kg (apparent Vd/F ~2500 L). |
| Bioavailability | Oral: Loratadine absolute bioavailability is ~40% due to first-pass metabolism; food increases AUC by 40% and delays Tmax. Desloratadine absolute bioavailability is ~50%. |
| Onset of Action | Oral: Symptom relief begins within 1-3 hours; maximum effect at 2-4 hours. |
| Duration of Action | 24 hours (clinical effect persists for 24 hours). Steady-state achieved after 5 days of once-daily dosing. |
| Molecular Weight | Loratadine: 382.88 g/mol; Pseudoephedrine: 165.23 g/mol |
1 tablet (10 mg loratadine/240 mg pseudoephedrine) orally once daily
| Dosage form | TABLET, EXTENDED RELEASE |
| Renal impairment | GFR 30-89 mL/min: no adjustment; GFR <30 mL/min or ESRD: contraindicated due to pseudoephedrine component |
| Liver impairment | Child-Pugh class A: no adjustment; Child-Pugh class B or C: contraindicated due to insufficient data |
| Pediatric use | Not recommended for children under 12 years; age 12-17 years: 1 tablet orally once daily |
| Geriatric use | Caution in patients >60 years due to increased sensitivity to pseudoephedrine (nervousness, dizziness, sleep disturbances) and higher risk of adverse effects; consider alternative therapy |
| 1st trimester | Limited data; use only if potential benefit justifies risk. Avoid in first trimester due to possible teratogenic effects of pseudoephedrine (minor risk of gastroschisis). |
| 2nd trimester | Use with caution; pseudoephedrine may reduce uterine blood flow. Avoid in cases of preeclampsia or hypertension. |
| 3rd trimester | Avoid near term; pseudoephedrine may cause uterine contractions and reduce placental perfusion. |
Clinical note
Comprehensive clinical and safety monograph for CLARITIN-D 24 HOUR (CLARITIN-D 24 HOUR).
| Placental transfer | Loratadine and its active metabolite desloratadine cross the placenta; pseudoephedrine also crosses. Degree: present, but not quantified in human studies. |
| Breastfeeding | Both loratadine and pseudoephedrine are excreted into breast milk in small amounts. Pseudoephedrine may cause irritability or drowsiness in the infant. Use with caution; prefer non-sedating antihistamines without decongestant. |
■ FDA Black Box Warning
None.
| Serious Effects |
Severe hypertensionCoronary artery diseaseConcurrent MAOI therapy or within 14 daysNarrow-angle glaucomaUrinary retentionSevere hepatic impairment (Child-Pugh C)
| Precautions | Cardiovascular effects: caution in hypertension, arrhythmias, ischemic heart disease, Central nervous system stimulation: may cause insomnia, dizziness, tremor, Urinary retention: caution in patients with prostatic hypertrophy, Glaucoma: may increase intraocular pressure, Use with MAOIs: hypertensive crisis risk, Diabetes: may increase blood glucose |
| Food/Dietary | Avoid high-tyramine foods (e.g., aged cheeses, cured meats, fermented products) due to potential hypertensive crisis with pseudoephedrine. Grapefruit juice may increase pseudoephedrine absorption; limit intake. Avoid alcohol, which can exacerbate CNS sedation from loratadine. |
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| Lactation Rating | L3 (Moderately Safe, but caution advised for pseudoephedrine; consider risk vs benefit) |
| Teratogenic Risk | FDA Pregnancy Category B. Animal studies show no fetal risk; no adequate human studies in first trimester. Pseudoephedrine may cause uterine vasoconstriction; avoid in preeclampsia or reduced placental perfusion. No known teratogenicity from loratadine or pseudoephedrine in human pregnancy. |
| Fetal Monitoring | Monitor maternal blood pressure and heart rate due to pseudoephedrine; assess for hypertension, tachycardia, or uterine hyperstimulation. No specific fetal monitoring required, but in hypertensive disorders, consider decreased placental blood flow. |
| Fertility Effects | No known adverse effects on fertility in human studies. Loratadine: no effect in animal studies. Pseudoephedrine: no specific data, but theoretical risk of uterine blood flow reduction without evidence of fertility impairment. |
| Clinical Pearls | CLARITIN-D 24 HOUR combines loratadine (antihistamine) and pseudoephedrine (decongestant). Avoid in patients with severe hypertension, coronary artery disease, or MAOI use within 14 days. Monitor for insomnia, tachycardia, and urinary retention, especially in elderly males with BPH. Contraindicated in narrow-angle glaucoma. |
| Patient Advice | Do not crush or chew the tablet; swallow whole with a full glass of water. · Avoid taking within 4-6 hours of bedtime to prevent insomnia. · Do not use with other decongestants or cold remedies containing pseudoephedrine. · Discontinue and consult healthcare provider if you experience chest pain, rapid heart rate, dizziness, or difficulty urinating. |