DELSYM
Clinical safety rating: caution
Comprehensive clinical and safety monograph for DELSYM (DELSYM).
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.
| Metabolism | Metabolized primarily by CYP2D6 to dextrorphan, an active metabolite; also undergoes O-demethylation and N-demethylation. |
| Excretion | Renal excretion of unchanged drug and metabolites, primarily dextrorphan glucuronide; <5% excreted unchanged in urine. Biliary/fecal elimination is negligible. |
| Half-life | 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. |
| Protein binding | ~45-50% bound to plasma albumin; main binding protein is albumin. |
| Volume of Distribution | 5-6 L/kg, indicating extensive tissue distribution. |
| Bioavailability | Oral: ~10-25% due to extensive first-pass metabolism (CYP2D6 and CYP3A4); bioavailability is higher in poor metabolizers. |
| Onset of Action | Oral: 15-30 minutes for cough suppression. |
| Duration of Action | 12 hours per single dose (extended-release formulation); clinical effect may last up to 12 hours due to sustained release mechanism. |
| Molecular Weight | 255.28 |
60 mg orally every 12 hours (extended-release suspension).
| Dosage form | SUSPENSION, EXTENDED RELEASE |
| Renal impairment | No dose adjustment recommended for mild-to-moderate renal impairment; safety in severe renal impairment not established. |
| Liver impairment | No dose adjustment recommended for mild-to-moderate hepatic impairment; safety in severe hepatic impairment not established. |
| Pediatric use | 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+. |
| Geriatric use | 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. |
| 1st trimester | Limited human data; animal studies not adequate. Avoid use unless clearly needed. |
| 2nd trimester | Avoid use, especially during third trimester, due to risk of premature closure of ductus arteriosus. |
| 3rd trimester | Contraindicated due to risk of premature closure of ductus arteriosus and oligohydramnios. |
Clinical note
Comprehensive clinical and safety monograph for DELSYM (DELSYM).
| Placental transfer | Crosses placenta; minimal data on degree. |
| Breastfeeding | Excreted into breast milk in small amounts; not expected to cause adverse effects in infants. Use caution in nursing mothers, especially with premature infants or those with renal impairment. |
| Lactation Rating |
■ FDA Black Box Warning
None
| Serious Effects |
Severe hypertensionSignificant aortic insufficiencyHistory of asthma or urticaria with NSAIDsPremature closure of ductus arteriosus (third trimester)
| Precautions | 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 |
| Food/Dietary | No significant food interactions. Avoid grapefruit juice as it may increase dextromethorphan levels. Take with or without food. |
| Clinical Pearls |
Loading safety data…
| L2 (Limited data - possibly compatible) |
| Teratogenic Risk | 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. |
| Fetal Monitoring | Monitor maternal respiratory rate and oxygen saturation, especially with prolonged or high-dose use. For fetal assessment: consider fetal nonstress test and biophysical profile if maternal respiratory depression suspected. Monitor neonatal adaptation for signs of opioid withdrawal (irritability, hypertonia, tremors) after delivery in women with chronic use. |
| Fertility Effects | No human data demonstrate negative effects on fertility. Animal studies show no impairment of fertility at clinically relevant doses. Potential indirect effects if chronic use leads to hypothalamic-pituitary-gonadal axis suppression (e.g., hypogonadism), but not documented with dextromethorphan. |
| 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). |
| Patient Advice | 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. |