LORATADINE AND PSEUDOEPHEDRINE SULFATE
Clinical safety rating: safe
MAOIs can cause hypertensive crisis Can cause insomnia and tachycardia.
Loratadine: Selective peripheral H1-receptor antagonist, reducing histamine-mediated allergic responses. Pseudoephedrine sulfate: Indirect sympathomimetic, releasing norepinephrine from presynaptic terminals, causing vasoconstriction and decongestion.
| Metabolism | Loratadine: Metabolized by CYP3A4 and CYP2D6 to active metabolite desloratadine. Pseudoephedrine: Partially metabolized by hepatic N-demethylation and excreted largely unchanged in urine. |
| Excretion | Loratadine and its metabolites are primarily excreted in urine (approximately 80%) and feces (approximately 20%). Pseudephedrine is predominantly excreted unchanged in urine (70-90%), with the remainder as inactive metabolites. |
| Half-life | Loratadine: 8-14 hours (terminal); its active metabolite descarboethoxyloratadine: 17-24 hours. Pseudephedrine sulfate: 5-8 hours (dependent on urine pH; alkaline urine prolongs half-life). |
| Protein binding | Loratadine: 97-99% bound to albumin and alpha-1-acid glycoprotein. Pseudephedrine sulfate: minimal binding (<5%). |
| Volume of Distribution | Loratadine: 122 L/kg (extensive tissue distribution). Pseudephedrine sulfate: 2.5-3.5 L/kg. |
| Bioavailability | Loratadine: Oral bioavailability ~40% (due to extensive first-pass metabolism). Pseudephedrine sulfate: Oral bioavailability ~100%. |
| Onset of Action | Loratadine: 1-3 hours orally. Pseudephedrine sulfate: 30-60 minutes orally. |
| Duration of Action | Loratadine: 24 hours. Pseudephedrine sulfate: 4-6 hours (sustained-release formulation may last up to 12 hours). Note: Clinical effect duration may vary with dosing formulation. |
One tablet (loratadine 5 mg/pseudoephedrine sulfate 120 mg) orally every 12 hours. Maximum: 2 tablets per day.
| Dosage form | TABLET, EXTENDED RELEASE |
| Renal impairment | Contraindicated if GFR < 30 mL/min. For GFR 30–50 mL/min: use with caution, consider reducing dose (e.g., loratadine 5 mg/pseudoephedrine sulfate 60 mg) every 12 hours. For GFR > 50 mL/min: no adjustment needed. |
| Liver impairment | Child-Pugh Class A or B: no adjustment. Child-Pugh Class C: loratadine should be avoided; consider alternative therapy. |
| Pediatric use | Children ≥12 years: same as adult dose (one tablet every 12 hours). Children 4–11 years: use loratadine 2.5 mg/pseudoephedrine sulfate 60 mg tablet every 12 hours; maximum 2 tablets per day. Children <4 years: not recommended. |
| Geriatric use | Elderly (≥65 years): start with lowest effective dose; due to increased sensitivity to sympathomimetics, consider loratadine alone. Use with caution for hypertension, arrhythmias, or prostatic hyperplasia. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
MAOIs can cause hypertensive crisis Can cause insomnia and tachycardia.
| FDA category | Animal |
| Breastfeeding | Loratadine: Excreted in breast milk; M/P ratio 1.17; considered compatible with breastfeeding. Pseudoephedrine: Excreted in breast milk; M/P ratio 2.6-3.5; may cause irritability in infants; avoid or use with caution; can reduce milk supply. |
| Teratogenic Risk | Loratadine: FDA Pregnancy Category B; no evidence of teratogenicity in animal studies, but no adequate human studies in first trimester. Pseudophedrine: FDA Pregnancy Category C; associated with increased risk of gastroschisis in first trimester, and may cause uterine vasoconstriction reducing placental perfusion in second and third trimesters. Avoid in first trimester due to potential vascular disruption defects. |
■ FDA Black Box Warning
None
| Common Effects | Insomnia |
| Serious Effects |
["Hypersensitivity to loratadine or pseudoephedrine","Severe hypertension or coronary artery disease","Concurrent use or recent use of MAO inhibitors","Narrow-angle glaucoma","Urinary retention"]
| Precautions | ["Do not use with other antihistamines or decongestants","Caution in patients with hypertension, cardiovascular disease, hyperthyroidism, diabetes, increased intraocular pressure, or prostatic hypertrophy","May cause dizziness or drowsiness; avoid driving or operating machinery","Avoid use with MAO inhibitors or within 14 days of stopping"] |
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| Fetal Monitoring | Monitor maternal blood pressure, heart rate, and signs of excessive stimulation (insomnia, nervousness). Fetal monitoring: assess for potential growth restriction if used chronically; consider nonstress test if evidence of reduced placental perfusion. |
| Fertility Effects | No known significant adverse effects on fertility with loratadine. Pseudoephedrine may theoretically affect uterine blood flow; no direct evidence of impaired fertility. |