Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
DELSYM vs BENZONATATE
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.
Benzonatate is a local anesthetic structurally related to tetracaine. It suppresses cough by anesthetizing stretch receptors in the respiratory tract, reducing the cough reflex.
Symptomatic relief of cough caused by minor throat and bronchial irritation
Symptomatic relief of cough
60 mg orally every 12 hours (extended-release suspension).
100 mg to 200 mg orally three times daily as needed for cough.
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.
Terminal elimination half-life is approximately 3–8 hours in adults; prolonged in hepatic impairment.
Metabolized primarily by CYP2D6 to dextrorphan, an active metabolite; also undergoes O-demethylation and N-demethylation.
Metabolized by plasma esterases (including pseudocholinesterase) to tetracaine and other metabolites.
Renal excretion of unchanged drug and metabolites, primarily dextrorphan glucuronide; <5% excreted unchanged in urine. Biliary/fecal elimination is negligible.
Primarily renal excretion of metabolites; unchanged benzonatate is negligible. Fecal elimination accounts for <5%. Biliary excretion is minimal.
~45-50% bound to plasma albumin; main binding protein is albumin.
Approximately 75–85% bound primarily to albumin.
5-6 L/kg, indicating extensive tissue distribution.
Approximately 3.5 L/kg, indicating extensive tissue distribution.
Oral: ~10-25% due to extensive first-pass metabolism (CYP2D6 and CYP3A4); bioavailability is higher in poor metabolizers.
Oral: Estimated 20–30% due to extensive first-pass metabolism.
No dose adjustment recommended for mild-to-moderate renal impairment; safety in severe renal impairment not established.
No specific dosage adjustment is recommended for renal impairment per manufacturer; however, caution and monitoring are advised.
No dose adjustment recommended for mild-to-moderate hepatic impairment; safety in severe hepatic impairment not established.
No specific dosage adjustment is recommended for hepatic impairment per manufacturer; however, caution is advised.
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+.
Safety and efficacy have not been established in children under 10 years of age. For children ≥10 years, adult dosing can be considered.
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.
Elderly patients may be more sensitive to CNS effects; start at lower end of dosing range (100 mg three times daily) and monitor carefully.
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
Severe allergic reactions (e.g., bronchospasm, laryngospasm, cardiovascular collapse) have been reported, especially with chewing or sucking capsules.,Capsules must be swallowed whole to avoid oral mucosal anesthesia and choking hazard.,Use with caution in patients with hypersensitivity to ester-type local anesthetics.,Safety and efficacy in children <10 years not established.
Hypersensitivity to dextromethorphan or any component,Use with or within 14 days of MAO inhibitors,Use in patients with respiratory depression or severe asthma
Hypersensitivity to benzonatate or related compounds (e.g., tetracaine, procaine)
No significant food interactions. Avoid grapefruit juice as it may increase dextromethorphan levels. Take with or without food.
No significant food interactions. The manufacturer does not list any specific dietary restrictions, but alcohol may enhance central nervous system side effects such as drowsiness.
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.
FDA Pregnancy Category C. First trimester: No adequate human studies; animal studies not available. Theoretical risk of fetal bradycardia and respiratory depression if used near term. Second and third trimesters: Avoid use due to potential for neonatal apnea and withdrawal; benzonatate is a local anesthetic with CNS depressant effects.
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.
No data on excretion in human milk; M/P ratio unknown. Benzonatate and its metabolites may be present in breast milk. Caution advised due to potential for infant CNS depression and apnea. Consider benefit of breastfeeding vs risk of drug exposure.
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 pharmacokinetic studies in pregnancy. Dose adjustments not established. Use lowest effective dose if necessary. Avoid in third trimester due to neonatal risk. Increased plasma volume may reduce drug levels, but lack of data prevents formal dose adjustment recommendations.
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).
Benzonatate is a peripherally acting antitussive that anesthetizes stretch receptors in the respiratory tract. Onset of action is within 15-20 minutes and lasts 3-8 hours. Capsules must be swallowed whole; chewing or sucking can cause oropharyngeal anesthesia and choking hazard. Use with caution in patients with a history of drug allergy to tetracaine or other ester-type anesthetics. It is contraindicated in children under 10 years due to increased risk of adverse effects. Overdose can cause seizures, cardiac arrest, and death; treatment is supportive with no specific antidote.
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.
Swallow the capsule whole; do not chew, suck, or crush it, as this can cause numbness in your mouth or throat and increase risk of choking.,Take the medication exactly as prescribed; do not take more than directed.,This medication may cause dizziness or drowsiness; avoid driving or operating machinery until you know how it affects you.,Contact your doctor if your cough persists for more than 5 days, or if it is accompanied by fever, rash, or persistent headache.,Keep out of reach of children; accidental ingestion can be fatal in children under 10.,Store at room temperature away from moisture and heat.
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 BENZONATATE, 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.. BENZONATATE is a Antitussive that works by Benzonatate is a local anesthetic structurally related to tetracaine. It suppresses cough by anesthetizing stretch receptors in the respiratory tract, reducing the cough reflex.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between DELSYM and BENZONATATE depend on the specific clinical indication. These are both Antitussive agents 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 BENZONATATE is: 100 mg to 200 mg orally three times daily as needed for cough.. 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 BENZONATATE 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. BENZONATATE is classified as Category A/B. FDA Pregnancy Category C. First trimester: No adequate human studies; animal studies not available. Theoretical risk of fetal bradycardia and respiratory depression if used near te. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.