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. |
| Molecular Weight | 390.54 |
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 | Avoid due to potential teratogenic effects; antihistamines and decongestants have shown associations with gastroschisis and other malformations in some studies. |
| 2nd trimester | Use with caution; decongestants (pseudoephedrine) may cause uteroplacental insufficiency and fetal tachycardia. Antihistamines (dexbrompheniramine) have limited safety data. |
| 3rd trimester | Avoid near term; decongestants may cause fetal tachycardia and uterine contractions; antihistamines may be associated with neonatal withdrawal symptoms. |
Clinical note
Comprehensive clinical and safety monograph for DRIXORAL PLUS (DRIXORAL PLUS).
| Placental transfer | Both active ingredients (dexbrompheniramine, pseudoephedrine) cross the placenta; pseudoephedrine has documented transfer in animal and human studies. |
| Breastfeeding | Both dexbrompheniramine and pseudoephedrine are excreted into breast milk in small amounts. Pseudoephedrine may reduce milk production. Observe infant for irritability, drowsiness, or poor feeding. |
■ FDA Black Box Warning
None.
| Serious Effects |
Severe hypertensionCoronary artery diseaseConcurrent MAOI therapy or within 14 daysNarrow-angle glaucomaUrinary retentionSevere hepatic or renal impairment
| 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. |
| Food/Dietary | Avoid high-tyramine foods (aged cheese, cured meats, fermented products) due to potential hypertensive crisis with pseudoephedrine. Also avoid caffeine or other stimulants as they may exacerbate CNS side effects. |
Loading safety data…
| Lactation Rating | L3: Limited data - Probably Compatible |
| 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. |
| 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. |
| Clinical Pearls | Drixoral Plus contains dexbrompheniramine (antihistamine) and pseudoephedrine (decongestant). Avoid in patients with severe hypertension, coronary artery disease, or MAOI use within 14 days. Monitor for anticholinergic effects (dry mouth, urinary retention) and CNS stimulation (insomnia, anxiety). Not recommended in children under 6 years. |
| Patient Advice | Do not exceed recommended dosage to avoid side effects like insomnia or rapid heartbeat. · Avoid alcohol and other CNS depressants as they may increase drowsiness. · Consult a doctor if you have high blood pressure, heart disease, glaucoma, or an enlarged prostate. · Do not use with other products containing antihistamines or decongestants. · Stop use and seek medical help if symptoms persist after 7 days or are accompanied by fever. |