Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
DELSYM vs DIMETANE-DX
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Dextromethorphan is a non-competitive NMDA receptor antagonist and sigma-1 receptor agonist, which suppresses cough by elevating the threshold for coughing in the medullary cough center.
Dimetane-DX contains brompheniramine (first-generation antihistamine) and dextromethorphan (NMDA receptor antagonist and sigma-1 agonist). Brompheniramine antagonizes histamine at H1 receptors, reducing allergic symptoms; dextromethorphan suppresses cough by acting on the cough center in the medulla oblongata via NMDA receptor antagonism and sigma-1 receptor activation.
Symptomatic relief of cough caused by minor throat and bronchial irritation
Relief of cough and upper respiratory symptoms associated with allergy or common cold (FDA-approved OTC use)
60 mg orally every 12 hours (extended-release suspension).
Adults and children ≥12 years: One tablet (brompheniramine 4 mg, dextromethorphan 10 mg, phenylephrine 10 mg) orally every 4 hours as needed, not to exceed 4 doses in 24 hours.
Terminal elimination half-life of dextromethorphan is approximately 11 hours (range 9-14 hours) in extensive metabolizers; in poor metabolizers (CYP2D6 deficiency), half-life can exceed 24 hours, leading to accumulation.
Brompheniramine: 25-30 hours; guaifenesin: 1 hour; dextromethorphan: 2-4 hours (CYP2D6 extensive metabolizers) or 20-40 hours (poor metabolizers).
Metabolized primarily by CYP2D6 to dextrorphan, an active metabolite; also undergoes O-demethylation and N-demethylation.
Brompheniramine is hepatically metabolized via CYP450 enzymes (primarily CYP2D6). Dextromethorphan is extensively metabolized by CYP2D6 to dextrorphan (active metabolite).
Renal excretion of unchanged drug and metabolites, primarily dextrorphan glucuronide; <5% excreted unchanged in urine. Biliary/fecal elimination is negligible.
Renal: 50-70% (brompheniramine) as metabolites and unchanged drug; guaifenesin metabolites primarily renal; dextromethorphan and metabolites renal. Biliary/fecal: minor.
~45-50% bound to plasma albumin; main binding protein is albumin.
Brompheniramine: 50-60% to albumin; guaifenesin: <5%; dextromethorphan: 60-70% to albumin.
5-6 L/kg, indicating extensive tissue distribution.
Brompheniramine: 1.5-2.0 L/kg; guaifenesin: 0.5-1.0 L/kg; dextromethorphan: 5-10 L/kg.
Oral: ~10-25% due to extensive first-pass metabolism (CYP2D6 and CYP3A4); bioavailability is higher in poor metabolizers.
Oral: brompheniramine 50-70%, guaifenesin 70-90%, dextromethorphan 40-60% (first-pass metabolism).
No dose adjustment recommended for mild-to-moderate renal impairment; safety in severe renal impairment not established.
e GFR 30–59 m L/min: Administer with caution and reduce frequency to every 6 hours. e GFR <30 m L/min: Avoid use due to risk of accumulation of dextromethorphan and phenylephrine.
No dose adjustment recommended for mild-to-moderate hepatic impairment; safety in severe hepatic impairment not established.
Child-Pugh Class A: No adjustment. Child-Pugh Class B: Reduce dosing interval to every 8 hours; use with caution. Child-Pugh Class C: Contraindicated due to extensive first-pass metabolism.
Children 6-11 years: 30 mg orally every 12 hours. Children 12 years and older: 60 mg orally every 12 hours. Do not exceed 60 mg in 24 hours for ages 6-11 or 120 mg for ages 12+.
Children 6–11 years: 5 m L (half the adult dose) of liquid formulation (brompheniramine 2 mg, dextromethorphan 5 mg, phenylephrine 5 mg per 5 m L) orally every 4 hours, max 4 doses/day. Children 2–5 years: 2.5 m L orally every 4 hours, max 4 doses/day. Children <2 years: Contraindicated.
Start at low end of dosing range; monitor for anticholinergic effects and sedation. No specific dose adjustment in elderly but caution due to increased sensitivity.
Age ≥65 years: Initiate at half the adult dose (e.g., one tablet every 8 hours) due to increased anticholinergic effects and risk of urinary retention, constipation, and dizziness. Avoid in frail elderly or those with cognitive impairment.
None
None.
Do not use in children under 4 years of age,Avoid use with MAO inhibitors or for 2 weeks after stopping,Chronic use may lead to dependence and abuse,Caution in patients with respiratory depression, asthma, or chronic obstructive pulmonary disease
Do not use with MAOIs or for 2 weeks after stopping MAOIs due to risk of serotonin syndrome (dextromethorphan).,Avoid use in patients with asthma, chronic bronchitis, emphysema, or persistent cough (may suppress cough reflex).,Use with caution in patients with glaucoma, prostatic hyperplasia, urinary retention, or hypertension (brompheniramine anticholinergic effects).,CNS depression risk: may cause drowsiness; avoid alcohol or other sedatives.
Hypersensitivity to dextromethorphan or any component,Use with or within 14 days of MAO inhibitors,Use in patients with respiratory depression or severe asthma
Concurrent MAOI therapy or within 14 days,Neonates or premature infants (brompheniramine),Breastfeeding (may suppress lactation; dextromethorphan safety not established),Severe hypertension or coronary artery disease (brompheniramine may increase heart rate)
No significant food interactions. Avoid grapefruit juice as it may increase dextromethorphan levels. Take with or without food.
Avoid concurrent use of tyramine-rich foods (e.g., aged cheeses, cured meats, soy sauce, fermented foods) due to risk of hypertensive crisis with sympathomimetic (phenylephrine). Grapefruit juice may increase dextromethorphan levels; avoid large amounts.
Category D (positive evidence of human fetal risk): First trimester exposure associated with rare reports of congenital malformations including cardiac defects and oral clefts based on observational studies. Second and third trimester use may cause fetal respiratory depression, bradycardia, and neonatal adaptation syndrome with prolonged use near term. Risks increase with higher doses and chronic use.
Dimetane-DX contains brompheniramine (antihistamine) and dextromethorphan (antitussive). First trimester: Limited human data; animal studies show no teratogenicity at therapeutic doses. Second and third trimesters: Avoid due to risk of neonatal respiratory depression, withdrawal symptoms, and anticholinergic effects. Dextromethorphan: No clear teratogenic risk, but avoid use. Overall: Contraindicated in pregnancy unless benefit outweighs risk.
Excreted into breast milk in low concentrations (M/P ratio 0.1–0.4). Considered compatible with breastfeeding by American Academy of Pediatrics; however, monitor infant for drowsiness, respiratory depression, and poor feeding. Avoid if infant is premature or has respiratory compromise. Use shortest duration possible.
Brompheniramine may suppress lactation and cause irritability in infants. Dextromethorphan is excreted in breast milk in small amounts (M/P ratio not well defined). Use with caution; consider alternative therapy.
No pharmacokinetic studies show significant changes in dextromethorphan clearance during pregnancy. Therefore, no empiric dose adjustment is recommended. However, because of increased plasma volume and renal blood flow in pregnancy, the duration of action may be shorter, requiring more frequent dosing if clinically indicated. Use lowest effective dose for shortest duration.
No specific dose adjustments are recommended for Dimetane-DX in pregnancy due to limited data. However, increased plasma volume and altered drug metabolism may reduce efficacy; clinicians should consider lowest effective dose and shortest duration. Avoid near delivery.
DELSYM (dextromethorphan polistirex) is a sustained-release formulation providing up to 12 hours of cough suppression. Do not crush or chew capsules; swallow whole. Avoid use in patients with asthma, COPD, or respiratory insufficiency due to risk of respiratory depression. Contraindicated with MAOIs and within 14 days of MAOI use due to serotonin syndrome risk. Not recommended for chronic cough or cough associated with excessive secretions. Use caution in patients with G6PD deficiency (rare hemolysis risk).
DIMETANE-DX combines brompheniramine (first-generation antihistamine), phenylephrine (decongestant), and dextromethorphan (antitussive). Avoid in hypertension, MAOI use, or asthma. Monitor for CNS depression and anticholinergic effects.
Take DELSYM only as directed for temporary cough relief.,Swallow capsules whole; do not crush, chew, or dissolve.,Do not exceed recommended dose or use for more than 7 days unless directed by a doctor.,Avoid alcohol while taking this medication.,Do not use if you are taking or have taken a monoamine oxidase inhibitor (MAOI) within the last 14 days.,Seek medical attention if cough persists, comes with fever, rash, or headache, or if you experience signs of serotonin syndrome (agitation, hallucinations, rapid heart rate, fever, muscle stiffness).,Keep out of reach of children; accidental overdose may cause death.
Do not drive or operate machinery until you know how this medication affects you; it may cause drowsiness or dizziness.,Avoid alcohol and other sedatives; they increase sedation and CNS depression.,Do not exceed recommended dosage or use for more than 7 days for cough.,Stop use and consult a doctor if symptoms persist or worsen, or if you develop fever, rash, or persistent headache.,Inform your healthcare provider if you have high blood pressure, heart disease, glaucoma, or urinary retention.
No interactions on record
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about DELSYM vs DIMETANE-DX, answered by our medical review team.
DELSYM is a Antitussive that works by Dextromethorphan is a non-competitive NMDA receptor antagonist and sigma-1 receptor agonist, which suppresses cough by elevating the threshold for coughing in the medullary cough center.. DIMETANE-DX is a Antitussive Combination that works by Dimetane-DX contains brompheniramine (first-generation antihistamine) and dextromethorphan (NMDA receptor antagonist and sigma-1 agonist). Brompheniramine antagonizes histamine at H1 receptors, reducing allergic symptoms; dextromethorphan suppresses cough by acting on the cough center in the medulla oblongata via NMDA receptor antagonism and sigma-1 receptor activation.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between DELSYM and DIMETANE-DX depend on the specific clinical indication. These are agents from distinct pharmacological classes and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of DELSYM is: 60 mg orally every 12 hours (extended-release suspension).. The standard adult dose of DIMETANE-DX is: Adults and children ≥12 years: One tablet (brompheniramine 4 mg, dextromethorphan 10 mg, phenylephrine 10 mg) orally every 4 hours as needed, not to exceed 4 doses in 24 hours.. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between DELSYM and DIMETANE-DX in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. DELSYM is classified as Category C. Category D (positive evidence of human fetal risk): First trimester exposure associated with rare reports of congenital malformations including cardiac defects and oral clefts base. DIMETANE-DX is classified as Category C. Dimetane-DX contains brompheniramine (antihistamine) and dextromethorphan (antitussive). First trimester: Limited human data; animal studies show no teratogenicity at therapeutic d. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.