DIMETANE-TEN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for DIMETANE-TEN (DIMETANE-TEN).
Dimetane-Ten is a combination of brompheniramine (antihistamine) and phenylephrine (decongestant). Brompheniramine competitively blocks histamine H1 receptors, reducing allergic symptoms; phenylephrine acts as an α1-adrenergic receptor agonist, causing vasoconstriction in nasal mucosa.
| Metabolism | Brompheniramine: Hepatic metabolism via CYP450 enzymes (CYP2D6 major), excreted renally. Phenylephrine: Metabolized by monoamine oxidase (MAO) in gut and liver; also undergoes sulfation and glucuronidation. |
| Excretion | Renal: ~50% as unchanged drug and metabolites; biliary/fecal: ~40% as metabolites; remainder as minor pathways. |
| Half-life | Terminal elimination half-life: 12-15 hours; clinical context: allows twice-daily dosing; prolonged in renal impairment. |
| Protein binding | ~78% bound to albumin. |
| Volume of Distribution | Vd: 0.7 L/kg; clinical meaning: distributes widely into total body water. |
| Bioavailability | Oral: ~40% due to first-pass metabolism; IM: ~70%; IV: 100%. |
| Onset of Action | Oral: 30-60 minutes; intramuscular: 15-30 minutes; intravenous: 5-10 minutes. |
| Duration of Action | Lasts 12-24 hours; clinical notes: Antihistaminic effects may wane after 12 hours; prolonged in hepatic impairment. |
| Molecular Weight | 350.88 |
One tablet (chlorpheniramine maleate 4 mg, phenylephrine HCl 10 mg, methscopolamine nitrate 2.5 mg) orally every 12 hours, not to exceed 2 tablets in 24 hours.
| Dosage form | INJECTABLE |
| Renal impairment | No specific guidelines available; use with caution in severe renal impairment (CrCl <30 mL/min) due to potential accumulation of active metabolites. Consider dose reduction or increased dosing interval. |
| Liver impairment | No specific guidelines available; use with caution in severe hepatic impairment (Child-Pugh class C) due to altered metabolism. Consider dose reduction or avoidance. |
| Pediatric use | Not recommended for children under 12 years of age due to lack of safety and efficacy data. For children 12 years and older, same as adult dose. |
| Geriatric use | Elderly patients are more sensitive to anticholinergic effects (e.g., confusion, urinary retention, constipation) and sympathomimetic effects (e.g., hypertension, tachycardia). Initiate at lowest effective dose, monitor closely, and consider dose reduction or alternative therapy. |
| 1st trimester | Avoid; antihistamines may cause fetal harm, lack of safety data. |
| 2nd trimester | Use only if clearly needed; potential risk of cleft palate not confirmed. |
| 3rd trimester | Avoid near term; risk of paradoxical CNS stimulation, respiratory depression in neonate. |
Clinical note
Comprehensive clinical and safety monograph for DIMETANE-TEN (DIMETANE-TEN).
| Placental transfer | Antihistamines cross placenta; limited data for Dimetane-Ten, but likely similar to others. |
| Breastfeeding | Excreted into breast milk; may cause drowsiness or irritability in infant. Use caution and monitor infant. |
| Lactation Rating |
■ FDA Black Box Warning
None
| Serious Effects |
Hypersensitivity to any componentMAOI therapySevere hypertensionCoronary artery diseaseNarrow-angle glaucomaSymptomatic prostatic hypertrophyBladder neck obstructionAsthma attackPremature infants or neonates
| Precautions | Caution in patients with hypertension, cardiovascular disease, diabetes, hyperthyroidism, or increased intraocular pressure, Avoid use with MAOIs or within 14 days of discontinuation, May cause drowsiness; avoid driving or operating machinery, Risk of urinary retention in patients with prostatic hypertrophy, Use in pregnancy only if clearly needed |
| Food/Dietary | Avoid caffeine-containing beverages (coffee, tea, cola) as they may increase stimulant effects. Take with food or milk if gastric upset occurs. Avoid tyramine-rich foods (e.g., aged cheese, cured meats) only if taking MAOIs; otherwise no specific restrictions. |
Loading safety data…
| L3 (Moderately Safe) |
| Teratogenic Risk | FDA Pregnancy Category C for antihistamines. First trimester: limited data, but increased risk of congenital malformations (cleft palate, inguinal hernia) reported with some antihistamines; avoid. Second/third trimester: use only if clearly needed; oxytocic effect on the uterus may enhance labor; paradoxical CNS stimulation in newborn if used near term. |
| Fetal Monitoring | Monitor for maternal CNS depression (drowsiness, dizziness) and anticholinergic effects (dry mouth, urinary retention). In fetus/newborn: monitor for signs of antihistamine toxicity (CNS stimulation or depression, respiratory depression) especially if used near term. Perform nonstress test and biophysical profile if used in third trimester. |
| Fertility Effects | No specific human studies; animal studies do not indicate direct impairment of fertility. Antihistamines may cause menstrual irregularities due to anticholinergic effects, but no proven impact on conception or spermatogenesis. |
| Clinical Pearls | Dimetane-Ten (brompheniramine maleate/phenylephrine) is a fixed-dose combination of a first-generation antihistamine and an alpha-1 agonist. Antihistaminergic effects may cause sedation; avoid concurrent CNS depressants. Phenylephrine is less effective orally than topical for decongestion. Use with caution in hypertension, hyperthyroidism, prostatic hypertrophy, and glaucoma. Contraindicated in severe coronary artery disease and MAOI use within 14 days. |
| Patient Advice | May cause drowsiness; avoid driving or operating heavy machinery until you know how you react. · Do not exceed recommended dosage; higher doses increase side effects like dizziness and rapid heartbeat. · Avoid alcohol and other sedatives while taking this medication. · Notify your doctor if you have high blood pressure, heart disease, thyroid problems, diabetes, or trouble urinating. · Do not use in children under 6 years without medical advice. · Report symptoms like chest pain, fast/irregular heartbeat, or severe dizziness immediately. |