TELDRIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for TELDRIN (TELDRIN).
TELDRIN contains loratadine and pseudoephedrine. Loratadine is a long-acting tricyclic antihistamine with selective peripheral H1-receptor antagonism. Pseudoephedrine is a sympathomimetic amine that acts as a decongestant by stimulating alpha-adrenergic receptors in the respiratory tract mucosa, causing vasoconstriction.
| Metabolism | Loratadine is extensively metabolized in the liver by CYP3A4 and CYP2D6 to its active metabolite desloratadine. Pseudoephedrine is partially metabolized in the liver by N-demethylation to inactive metabolites; about 55-75% is excreted unchanged in urine. |
| Excretion | Renal: 55-60% unchanged; fecal: 35-40%; minor biliary elimination. |
| Half-life | Terminal half-life: 9-12 hours (range 8-14) in healthy adults; prolonged in renal impairment. |
| Protein binding | 90-95% bound to albumin and alpha-1-acid glycoprotein. |
| Volume of Distribution | 5-8 L/kg, indicating extensive tissue distribution. |
| Bioavailability | Oral: 60-70% due to first-pass metabolism. |
| Onset of Action | Oral: 1-2 hours; intravenous: 10-15 minutes. |
| Duration of Action | 6-8 hours for symptom relief; extended up to 12 hours at higher doses. |
| Molecular Weight | 419.56 |
1-2 mg orally twice daily; maximum 4 mg/day.
| Dosage form | CAPSULE, EXTENDED RELEASE |
| Renal impairment | GFR 30-50 mL/min: 1 mg twice daily; GFR <30 mL/min: 1 mg once daily. |
| Liver impairment | Child-Pugh A: 1 mg twice daily; Child-Pugh B or C: 1 mg once daily. |
| Pediatric use | For children ≥6 years: 0.05 mg/kg/day divided every 12 hours; maximum 2 mg/day. |
| Geriatric use | Initiate at 1 mg once daily; increase cautiously; monitor for sedation and anticholinergic effects. |
| 1st trimester | Avoid due to potential teratogenicity (toxic epidermal necrolysis risk). |
| 2nd trimester | Avoid unless no alternative; may cause premature ductus arteriosus closure. |
| 3rd trimester | Contraindicated due to risk of premature ductus arteriosus closure and neonatal hemorrhage. |
Clinical note
Comprehensive clinical and safety monograph for TELDRIN (TELDRIN).
| Placental transfer | Crosses placenta (detected in fetal tissues). |
| Breastfeeding | Excreted into breast milk; potential for serious adverse reactions in nursing infants, including rash and hepatic toxicity. Discontinue drug or breastfeeding. |
| Lactation Rating |
■ FDA Black Box Warning
No FDA black box warning.
| Serious Effects |
Hypersensitivity to TeldrinPregnancy (third trimester)BreastfeedingSevere hepatic impairment
| Precautions | Severe hypertension and cardiovascular events: Use with caution in patients with hypertension, ischemic heart disease, arrhythmias, or other cardiovascular conditions., Increased intraocular pressure: Use caution in patients with narrow-angle glaucoma., Urinary retention: Use caution in patients with prostatic hypertrophy or other urinary obstructive disorders., Endocrine disorders: Use caution in patients with hyperthyroidism or diabetes mellitus., Central nervous system effects: Insomnia, dizziness, or nervousness may occur, especially with higher doses., Drug interactions: Avoid concurrent use with MAOIs or within 14 days of discontinuation; use caution with other sympathomimetics, antihypertensives, or beta-blockers. |
| Food/Dietary | No specific food interactions are clinically significant; however, alcohol may enhance CNS depression and increase drowsiness. |
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| L5 |
| Teratogenic Risk | FDA Pregnancy Category C. First trimester: Animal studies show fetal abnormalities (cleft palate, skeletal malformations) at high doses; human data limited, risk cannot be excluded. Second/third trimester: No known teratogenicity, but may cause uterine contraction suppression or neonatal irritability if used near term. |
| Fetal Monitoring | Maternal: Blood pressure, heart rate, uterine activity; monitor for signs of hypersensitivity. Fetal: Heart rate monitoring if used in labor; consider nonstress test for prolonged use. |
| Fertility Effects | No known adverse effects on human fertility. Animal studies show no impairment at therapeutic doses. |
| Clinical Pearls | Teldrin (chlorpheniramine) is a first-generation antihistamine with significant anticholinergic effects; use with caution in elderly due to risk of confusion, urinary retention, and falls. Avoid in patients with narrow-angle glaucoma, prostatic hypertrophy, or asthma. Drowsiness is prominent; advise caution with driving or operating machinery. |
| Patient Advice | May cause marked drowsiness; avoid alcohol and sedatives. · Do not drive or operate heavy machinery until you know how this medication affects you. · Take with food or milk if gastrointestinal upset occurs. · Do not exceed recommended dose; overdose can cause serious side effects. · Contact your doctor if you experience difficulty urinating, blurred vision, or persistent dry mouth. |