Key Recommendations

Work down the steps and stop at the first box that refers the patient. Red boxes mean emergency department, amber means follow-up or coingestant triage, and green means home.

Products and Sources of Exposure

The product, not the DXM dose alone, decides the risk. DXM is sold as the hydrobromide salt in syrups, liquid-filled capsules, tablets and lozenges; the usual maximum OTC adult dose is 120 mg per day.

DXM-containing OTC cough products are not recommended for young children, and many U.S. states restrict sales to minors.

Epidemiology

Poison center calls involving DXM fall into three groups with different risks: exploratory ingestions in young children, intentional misuse in adolescents and young adults, and therapeutic errors or interactions in adults.

• Misuse peaked and then declined. In NPDS, single-substance DXM abuse calls tripled from 2000 to 2006 and then plateaued. Rates were highest at ages 14 to 17 and fell by 56% in that group between 2006 and 2015. [10]

• Recent adult data (2015 to 2023). An FDA analysis of NPDS found that adult misuse exposures had been falling sharply before COVID-19; increases during the pandemic were small. Unintentional therapeutic errors rebounded, especially in women, and exceeded pre-pandemic levels by 2023. [12]

• Recent pediatric data. In children aged 6 to 17, intentional cold and cough exposures were mostly suspected suicide, with abuse or misuse the second most common reason; adolescents dominated. [11]

• Young children. A 2008 to 2014 U.S. surveillance study found 773 cases with an adverse event after a DXM-only product. Of these, 60% involved children younger than 4 years, 78% followed an overdose, and none were fatal; ataxia and tachycardia were the most common effects. [15]

NPDS counts are reported exposures, not confirmed poisonings, and do not capture every case.

Pharmacology and Mechanisms of Toxicity

DXM is the d-isomer of a morphinan but has negligible mu-opioid activity; its toxicity is dissociative and serotonergic, not opioid. Sigma receptors are no longer classified as opioid receptors. [3]

Flushing or urticarial rash (18%) and dystonia (5%) were also reported in pediatric DXM-only adverse events; their mechanism is not established. [15]

Pharmacokinetics and Drug Interactions

CYP2D6 activity and formulation decide how long a DXM exposure lasts. Immediate-release DXM generally peaks within 2 to 3 hours; extended-release polistirex has delayed and prolonged absorption and must be considered separately.

• Metabolism. CYP2D6 O-demethylates DXM to dextrorphan; CYP3A4 forms minor metabolites. Clearance of parent DXM depends mainly on CYP2D6 activity rather than renal excretion; its metabolites are excreted in urine, and the effect of severe renal impairment is not well characterized. [17]

• Poor metabolizers. About 5% to 10% of people of European ancestry lack CYP2D6 activity. They accumulate parent DXM and may have longer, more serotonergic toxicity.

• CYP2D6 inhibitors. Quinidine, bupropion, fluoxetine and paroxetine convert extensive metabolizers toward the poor-metabolizer pattern. Bupropion in Auvelity gives nonlinear, greater than dose-proportional DXM exposure. [2]

• Serotonergic co-medications. MAOIs, SSRIs, SNRIs, linezolid, methylene blue, tramadol and meperidine add serotonin toxicity risk. MAOI combinations carry the highest risk.

• Extracorporeal removal. No evidence supports hemodialysis or other extracorporeal removal for DXM.

Clinical Presentation

DXM toxicity looks dissociative and sympathomimetic: ataxia, nystagmus, agitation and tachycardia are the signature findings. Effects of immediate-release products usually begin within an hour.

Dose is a weak predictor of severity. The consensus guideline's evidence review found case reports with symptoms after 5 to 21 mg/kg in young children given combination or extended-release products; most doses were unverified and coingestants could not be excluded. The 5 and 7.5 mg/kg values used in triage below are operational referral thresholds, not toxicity cutoffs. Earlier statements that “moderate toxicity occurs at 7.7 mg/kg and severe at 7.8 mg/kg” have no biological meaning and should not be used. [5]

Serotonin Toxicity

Suspect it when DXM is taken with an MAOI, SSRI, SNRI, linezolid or another serotonergic drug, or in a large ingestion.

Diagnose with the Hunter criteria:

• spontaneous clonus;

• inducible or ocular clonus with agitation or diaphoresis;

• tremor with hyperreflexia; or

• hypertonia with temperature above 38 °C and ocular or inducible clonus. [7]

Cerebellar Edema in Young Children (DANCE)

Small case series, mainly from India, describe children under 5 years with sudden unresponsiveness after DXM-containing cough syrup and cytotoxic edema of both cerebellar hemispheres on MRI, resembling opioid-associated POUNCE syndrome.

Two further children recovered fully with supportive care and IV methylprednisolone. Causality and mechanism are unproven, and a role for coformulated ingredients has not been excluded.

Consider brain MRI in a young child with persistent or otherwise unexplained encephalopathy, coma or marked ataxia after a DXM-containing product, particularly when the course is atypical or not improving.

Reserve neurosurgical consultation for demonstrated cerebellar edema with mass effect or hydrocephalus. [1] [19]

Chronic Heavy Use

Repeated use of DXM hydrobromide can cause bromism: confusion, ataxia, psychosis and stupor. Bromide interferes with chloride assays, producing spurious hyperchloremia and a low or negative anion gap. Chronic misuse is also linked to mania, psychosis and dependence. [14]

Poison Center Triage

Apply the checks in order and stop at the first that sends the patient to an emergency department.

The dose thresholds come from the AAPCC consensus guideline and apply to children and adults alike; they are valid only for isolated, unintentional ingestion of an immediate-release product. [5]

Modifiers That Extend Follow-Up

• Serotonergic co-medication (MAOI, SSRI and similar): poison center follow-up every 2 hours for 8 hours [Chyka D]. For a patient taking an MAOI, consider ED referral for any ingestion above a therapeutic dose (expert opinion).

• Extended-release polistirex: the 4-hour window does not cover delayed absorption. Extend follow-up to at least 8 hours from ingestion, and refer if symptoms appear (expert opinion; not studied).

• Known poor metabolizer or CYP2D6 inhibitor: expect slower onset and longer effects; use the same thresholds but a longer follow-up window (expert opinion).

At home: do not induce emesis, and do not give activated charcoal [Chyka D].

The previous MedicalToxic.com threshold that allowed home management of children up to 10 mg/kg is retired; it was not supported by the cited consensus guideline.

Emergency Department Evaluation and Testing

The ED workup aims to find the coingestant, serotonin toxicity and hyperthermia; there is no useful DXM level.

Examine core temperature, mental status, pupils, nystagmus, tone, reflexes and clonus at arrival and at each reassessment.

Urine drug screens. DXM is associated with false-positive phencyclidine immunoassays. A positive PCP screen in a DXM exposure needs confirmation and should not change management. [16]

Serum DXM concentrations are not available in a clinically useful time and do not guide treatment.

Management

Treatment is supportive and symptom-directed: benzodiazepines, active cooling and airway support manage almost every severe case. There is no specific antidote.

The charcoal approach above uses the DXM-specific consensus guideline and, where explicitly stated, extrapolation from the 2026 CTRC activated-charcoal recommendations. [5] [9]

After medical stabilization, every intentional ingestion must have a psychiatric or behavioral health assessment, and adolescents with misuse should be offered substance use counseling.

Combination Products and Coingestants

The coingestant often causes the serious morbidity. In one report of adolescent Coricidin cases, one patient had prolonged anticholinergic toxicity and another developed acetaminophen hepatotoxicity after recreational use of a flu product. [13]

Special Populations

• Young children. Most exploratory ingestions of DXM-only products cause mild CNS and autonomic effects. Large polistirex ingestions can be life-threatening: a 23-month-old who took 71.4 mg/kg of DXM polistirex needed intubation, with toxicity lasting as long as the formulation's duration of action. Therapeutic dosing errors are common; OTC cough products are not recommended for young children. [18]

• Adolescents and young adults. Intentional misuse always goes to the ED. Ask about Coricidin and acetaminophen products, alcohol and other drugs, and screen for self-harm.

• Older adults and prescription users. Patients on Nuedexta or Auvelity, including those with dementia, face therapeutic errors and serotonergic polypharmacy. Assess the quinidine or bupropion component separately.

• CYP2D6 poor metabolizers. Expect delayed onset, higher parent DXM exposure and longer duration; extend observation.

• Pregnancy. Therapeutic DXM use was not associated with more major malformations than baseline. Overdose management is the same; the best fetal care is maternal stabilization, with obstetric consultation when the fetus is viable. Auvelity is not recommended in pregnancy. [8]

Disposition and Observation

Observation length follows the formulation and the interaction risk, not the dose alone. Windows longer than 4 hours below are expert opinion.

Admit patients with persistent moderate effects, repeated benzodiazepine needs, serotonin toxicity or seizures.

Admit to ICU for hyperthermia above 40 °C, coma, respiratory depression, refractory agitation or seizures.

Consult a medical toxicologist for severe toxicity, serotonin toxicity, prescription DXM combinations, suspected bromism or suspected cerebellar edema in a child.

Before discharge, intentional ingestions need behavioral health clearance; families of young children need safe-storage advice.

Prevention and Public Health

Age-restricted sales are already widespread. California first banned DXM sales to minors in 2012, and 21 states had age-18 sales laws by July 2021. [6]

• Families: store all cough and cold products up and away; use the dosing device supplied; do not combine products with overlapping ingredients; avoid OTC cough products in young children.

• Adolescents: parents, schools and pharmacists should recognize misuse signs and Coricidin or bulk-powder purchases.

• Prescribers and pharmacists: check for serotonergic drugs and CYP2D6 inhibitors before recommending DXM, and screen for duplicate DXM or bupropion before starting Auvelity.

• Poison centers: report DXM cases to NPDS with product and intent coded, so prescription combinations and polistirex exposures can be tracked separately.

Evidence Gaps

Most recommendations here rest on case reports, case series and consensus; none is supported by a randomized trial.

• The 5 and 7.5 mg/kg thresholds date from 2007 and have not been validated prospectively.

• The toxic dose and kinetics of polistirex overdose are not defined; the 8-hour observation window is expert opinion.

• Overdose data for Auvelity and Nuedexta are sparse.

• Activated charcoal has no DXM-specific outcome data.

• Cyproheptadine and naloxone benefit in DXM toxicity rests on case reports.

• DANCE syndrome has fewer than ten published cases; incidence, mechanism and the role of corticosteroids are unknown.