DEXBROMPHENIRAMINE MALEATE AND PSEUDOEPHEDRINE SULFATE
Clinical safety rating: safe
MAOIs can cause hypertensive crisis Can cause insomnia and tachycardia.
Dexbrompheniramine is a first-generation antihistamine that competitively antagonizes histamine at H1 receptors, reducing allergic symptoms. Pseudoephedrine is a sympathomimetic amine that directly stimulates alpha-adrenergic receptors, causing vasoconstriction and decongestion.
| Metabolism | Dexbrompheniramine is primarily metabolized by CYP3A4 and CYP2D6. Pseudoephedrine is partially metabolized by N-demethylation and oxidative deamination, with about 43-96% excreted unchanged in urine. |
| Excretion | Dexbrompheniramine and its metabolites are primarily excreted renally (approximately 80-85% of a dose as unchanged drug and metabolites). Pseudophedrine is largely excreted unchanged in urine (70-90%) via glomerular filtration and tubular secretion; the remainder is hepatically metabolized. Biliary/fecal elimination is minimal (<5%). |
| Half-life | Dexbrompheniramine: terminal elimination half-life is approximately 12-25 hours in adults. Pseudophedrine: terminal elimination half-life is about 5-8 hours in adults with normal renal function; it is prolonged in patients with renal impairment. |
| Protein binding | Dexbrompheniramine: approximately 90% bound to plasma proteins. Pseudophedrine: negligible protein binding (<10%). |
| Volume of Distribution | Dexbrompheniramine: Vd is approximately 3-5 L/kg, indicating extensive tissue distribution. Pseudophedrine: Vd is approximately 2.5-3.5 L/kg. |
| Bioavailability | Both components are well absorbed orally. Dexbrompheniramine: oral bioavailability is approximately 60-80%. Pseudophedrine: oral bioavailability is about 90-100%. |
| Onset of Action | Oral: Dexbrompheniramine's antihistamine effects begin within 1-2 hours. Pseudophedrine's decongestant effect begins within 30-60 minutes. |
| Duration of Action | Dexbrompheniramine: duration of antihistamine effect is up to 24 hours, allowing once-daily dosing. Pseudophedrine: immediate-release formulations provide decongestant effect for 4-6 hours; extended-release formulations last 12-24 hours. |
1 tablet (each containing dexchlorpheniramine maleate 2 mg/pseudoephedrine sulfate 120 mg) orally every 12 hours; maximum 2 tablets per day.
| Dosage form | TABLET, EXTENDED RELEASE |
| Renal impairment | GFR 30-50 mL/min: extend interval to every 12-24 hours; GFR <30 mL/min: contraindicated due to risk of accumulation. |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 50% or extend interval; Child-Pugh C: contraindicated. |
| Pediatric use | Not recommended for children under 12 years; for ages 12+: same as adult dosing. |
| Geriatric use | Start at lowest effective dose (e.g., 1 tablet daily) due to increased sensitivity to anticholinergic effects and risk of confusion; monitor for urinary retention and hypertension. |
| 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 | Probable compatibility (American Academy of Pediatrics rating). Pseudoephedrine is excreted into breast milk in small amounts (M/P ratio ~3.3); may cause irritability and sleep disruption in infants. Dexbrompheniramine may suppress lactation. Consider using alternatives with lower risk. |
| Teratogenic Risk | First trimester: Avoid; limited human data, but theoretical risk of antihistamine-related malformations. Second and third trimesters: Caution; pseudoephedrine may reduce uterine blood flow and cause fetal tachycardia. |
■ FDA Black Box Warning
None.
| Common Effects | Insomnia |
| Serious Effects |
["Hypersensitivity to any component","Severe hypertension or coronary artery disease","Concurrent use of monoamine oxidase inhibitors (MAOIs) or within 14 days of discontinuation","Narrow-angle glaucoma","Urinary retention","Severe hepatic or renal impairment"]
| Precautions | ["Cardiovascular effects: hypertension, palpitations, arrhythmias; use cautiously in cardiovascular disease","CNS stimulation: nervousness, dizziness, insomnia; avoid in severe hypertension or coronary artery disease","Anticholinergic effects: urinary retention, blurred vision; caution in glaucoma or prostatic hypertrophy","Drug interactions: MAO inhibitors, sympathomimetics, antihypertensives"] |
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| Fetal Monitoring | Monitor maternal blood pressure and heart rate due to pseudoephedrine. In late pregnancy, monitor fetal heart rate and uterine activity if used near term. |
| Fertility Effects | No known effects on fertility. However, antihistamines may interfere with ovulation in animal studies; human data limited. |