DRIXORAL PLUS
Clinical safety rating: caution
Comprehensive clinical and safety monograph for DRIXORAL PLUS (DRIXORAL PLUS).
DRIXORAL PLUS contains dexbrompheniramine, an antihistamine that competes with histamine for H1-receptor sites, suppressing histamine-induced symptoms; and pseudoephedrine, a sympathomimetic amine that directly acts on alpha-adrenergic receptors in the respiratory tract mucosa, causing vasoconstriction and reducing nasal congestion.
| Metabolism | Dexbrompheniramine is extensively metabolized in the liver via N-dealkylation. Pseudoephedrine is partially metabolized in the liver by N-demethylation and also excreted unchanged in urine. |
| Excretion | Renal: 50-70% unchanged for pseudoephedrine; hepatic metabolism for dexbrompheniramine with renal excretion of metabolites. |
| Half-life | Pseudoephedrine: ~9-16 hours (pH-dependent, longer in alkaline urine). Dexbrompheniramine: ~20-25 hours. Clinical context: multiple dosing accumulates. |
| Protein binding | Pseudoephedrine: negligible (<10%). Dexbrompheniramine: ~72% bound, primarily to albumin. |
| Volume of Distribution | Pseudoephedrine: 2.6-3.5 L/kg. Dexbrompheniramine: 6-8 L/kg. Indicates extensive tissue distribution. |
| Bioavailability | Oral pseudoephedrine: ~90-100%. Dexbrompheniramine: ~50-60% due to first-pass metabolism. |
| Onset of Action | Oral: pseudoephedrine 15-30 minutes, dexbrompheniramine 1-2 hours. |
| Duration of Action | Pseudoephedrine: 4-6 hours (immediate-release); dexbrompheniramine: 8-12 hours. Extended-release formulation provides 12-hour duration. |
1 tablet orally every 12 hours, not to exceed 2 tablets in 24 hours.
| Dosage form | TABLET, EXTENDED RELEASE |
| Renal impairment | GFR 30-89 mL/min: no adjustment; GFR 15-29 mL/min: use with caution, consider reducing dose; GFR <15 mL/min: contraindicated due to accumulation of pseudoephedrine. |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: use with caution, consider reducing dose; Child-Pugh C: contraindicated. |
| Pediatric use | Not recommended for children under 12 years. For children 12 years and older: same as adult dose. |
| Geriatric use | Start at half dose (1/2 tablet) orally every 12 hours due to increased sensitivity to anticholinergic effects and cardiovascular effects; monitor for confusion, urinary retention, and hypertension. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for DRIXORAL PLUS (DRIXORAL PLUS).
| Breastfeeding | Pseudoephedrine: M/P ratio ~3.1; excreted into breast milk; may cause irritability and reduced milk supply. Chlorpheniramine: excreted in trace amounts; M/P ratio not established; potential for sedation in infant. Avoid breastfeeding while taking DRIXORAL PLUS. |
| Teratogenic Risk | DRIXORAL PLUS contains pseudoephedrine and chlorpheniramine. Pseudoephedrine is category C; associated with increased risk of gastroschisis and hemifacial microsomia if used in first trimester. Avoid in first trimester. Chlorpheniramine is category B; generally considered low risk. In second and third trimesters, pseudoephedrine may cause uterine vasoconstriction and reduce placental perfusion; use caution. |
■ FDA Black Box Warning
None.
| Serious Effects |
["Hypersensitivity to dexbrompheniramine, pseudoephedrine, or any component of the formulation.","Severe hypertension or coronary artery disease.","Concurrent use or within 14 days of MAO inhibitor therapy.","Narrow-angle glaucoma.","Urinary retention.","Severe renal or hepatic impairment.","Children under 12 years of age (due to pseudoephedrine risk).","Breastfeeding (contraindicated due to pseudoephedrine excretion)."]
| Precautions | ["Cardiovascular effects: May cause hypertension, palpitations, and tachycardia, especially in patients with cardiovascular disease.","CNS stimulation: May cause nervousness, dizziness, or insomnia.","Anticholinergic effects: May cause dry mouth, urinary retention, and blurred vision; use cautiously in patients with glaucoma, prostatic hypertrophy, or urinary obstruction.","Avoid use in patients with severe hypertension or coronary artery disease.","Do not use with MAO inhibitors or within 14 days of stopping such therapy."] |
Loading safety data…
| Fetal Monitoring | Monitor maternal blood pressure and heart rate due to pseudoephedrine. Assess fetal heart rate and uterine activity if used in third trimester. Monitor for signs of reduced fetal movement. |
| Fertility Effects | Pseudoephedrine may affect fertility by altering cervical mucus consistency. Chlorpheniramine may cause anticholinergic effects on male and female reproductive tracts. No human studies on fertility impact. |