Dextromethorphan
Dextromethorphan hydrobromide
Brand names:Robitussin DM, Delsym, Mucinex DM
A non-opioid centrally acting antitussive widely available over the counter for cough suppression. Dextromethorphan is structurally related to opioids but lacks significant analgesic and respiratory depressant effects at standard antitussive doses. Operationally useful in deployment medicine for upper respiratory infections that produce disruptive cough.
Pharmacology and Actions
Dextromethorphan acts at multiple CNS targets including sigma-1 receptor agonism and NMDA receptor antagonism. The antitussive effect appears to be mediated through suppression of the medullary cough center. The drug is metabolized to dextrorphan, which is also active. At supratherapeutic doses, dextromethorphan produces dissociative effects similar to ketamine through NMDA antagonism, which is why the drug is sometimes abused recreationally.
Indications
- Nonproductive cough from upper respiratory infection
- Cough disruption of sleep or operational tasks
- Symptomatic cough relief when productive cough has been addressed with hydration and expectorants
Absolute Contraindications
- Known dextromethorphan allergy
- Concurrent MAOI use within 14 days (serotonin syndrome risk)
- Productive cough that should not be suppressed (pneumonia with sputum production)
- Cough with hemoptysis (warrants evaluation, not suppression)
- Severe hepatic impairment
Precautions and Side Effects
Drowsiness, dizziness, and GI upset can occur. Serotonin syndrome risk with MAOI use is the major drug interaction concern. Recreational abuse at high doses (10x to 50x therapeutic) produces dissociation, hallucinations, and can cause serotonin syndrome, hyperthermia, and seizures. Dextromethorphan-containing products frequently combine with acetaminophen, decongestants, and antihistamines; check all ingredients before administration to avoid duplication. Some patients are poor CYP2D6 metabolizers and may experience exaggerated effects.
Adult Dosing
Pediatric Dosing
Pediatric dosing: 4 to 6 years, 2.5 to 7.5 mg PO every 4 hours. 6 to 12 years, 5 to 10 mg PO every 4 hours. 12 years and older, adult dosing. Avoid in children under 4 years per FDA guidance on OTC cough and cold medications.
Pharmacokinetics
Peak Effect: PO: 2 to 4 hours
Duration: 3 to 6 hours (IR); 12 hours (ER)
Storage and Handling
Store liquids and tablets at controlled room temperature (15 to 30 degrees Celsius). Protect from light. Liquid formulations may have shorter shelf life after opening.
Reconstitution:
Tablets, capsules, and liquid require no reconstitution.
TCCC and TECC Role
Dextromethorphan is not a TCCC trauma management agent but is useful in deployment medicine for managing disruptive cough that interferes with sleep, mission capability, or noise discipline. An operationally significant cough at the wrong time and place is a real concern in tactical environments, and dextromethorphan offers reasonable cough suppression without the respiratory depression of opioid antitussives. The drug is not appropriate for productive cough or cough with hemoptysis.
Dextromethorphan is the cough suppressant carried in deployment kits for the URI that produces disruptive nonproductive cough at the wrong time. For tactical situations requiring noise discipline, suppressing a persistent cough can be operationally significant. The 30 mg dose every 6 to 8 hours is well-tolerated by most adults. Watch for the MAOI interaction; it is uncommon but the serotonin syndrome risk is real. Many OTC cough and cold combination products contain DXM along with acetaminophen, decongestants, and antihistamines; check the labels carefully to avoid dose duplication.
Suppressing a productive cough with dextromethorphan when the cough is clearing significant secretions from pneumonia or bronchitis. Cough suppression in this context can lead to mucus retention and worsening infection. Reserve dextromethorphan for nonproductive cough. The other common error is duplicating dextromethorphan dosing through combination products that contain DXM alongside other ingredients.
This drug profile is provided as educational reference material for trained medical providers. It is not medical advice, not a substitute for formal training, and not a substitute for current published guidelines or medical direction.
Drug administration is governed by your scope of practice, agency standing orders, medical director protocols, and applicable state and federal regulations. Controlled substances are subject to additional handling, accountability, and documentation requirements per DEA and state law. Always verify dosing, indications, contraindications, and route of administration against current published guidelines and your local protocols before administration.
If this content is being viewed during a medical emergency, call 911 immediately and follow the direction of your local emergency dispatch and medical control. Do not use this reference as a substitute for emergency medical services.
Drug information evolves. Last reviewed dates and source citations are provided for each entry. Confirm currency against the cited source before clinical use.
Penn Tactical Solutions publishes this reference for educational purposes. PTS does not provide medical direction and does not assume responsibility for clinical decisions made in the field. Clinical responsibility rests with the administering provider, their medical director, and their agency.
Educational reference for trained medical providers. Not medical advice. Not a substitute for formal training, current published guidelines, or medical direction. Drug administration is governed by your scope of practice, agency standing orders, medical director protocols, and applicable state and federal regulations. Controlled substances require additional storage, accountability, and documentation per DEA and state law.
In a medical emergency, call 911. This reference is not a substitute for emergency medical services.
Verify dosing, indications, and contraindications against current published guidelines and your local protocols before administration. Confirm content currency against the source citation. Penn Tactical Solutions does not provide medical direction. Clinical responsibility rests with the administering provider, their medical director, and their agency.
Dextromethorphan
| PO | Immediate release: 10 to 20 mg PO every 4 hours, maximum 120 mg/24 hours. Extended-release (Delsym): 60 mg PO every 12 hours. (15 to 30 minutes) |