Dextromethorphan at a glance: schedule, half-life, and class
- Generic name
- Dextromethorphan hydrobromide
- Brand names
- Delsym, Robitussin DM, Mucinex DM, NyQuil, Coricidin HBP; prescription: Auvelity, Nuedexta
- Drug class
- Antitussive; NMDA receptor antagonist and sigma-1 agonist; serotonin reuptake inhibitor
- US legal status
- Over the counter; not federally controlled; age limits in many states
- Approved uses
- Cough; major depression (Auvelity); pseudobulbar affect (Nuedexta)
- Maximum OTC dose
- 120 mg in 24 hours for adults
- Onset
- 15 to 30 minutes
- Broken down by
- CYP2D6 to dextrorphan
Dextromethorphan uses: what it is used for
Dextromethorphan quiets the cough reflex in the brain. It is in more than 100 over-the-counter cough and cold products.[1]
In 2022 the FDA approved Auvelity, which combines dextromethorphan with bupropion, as a rapid-acting treatment for major depression. Nuedexta, with quinidine, treats pseudobulbar affect, uncontrollable laughing or crying after brain injury.[2]
How much dextromethorphan is safe to take?
These directions come from the over-the-counter Drug Facts label. Many products also contain acetaminophen, antihistamines, or decongestants, so check every ingredient.[1]
| Product or group | Label directions | Notes |
|---|---|---|
| Immediate release, adults and children 12 and over | 10 to 20 mg every 4 hours or 30 mg every 6 to 8 hours | No more than 120 mg in 24 hours |
| Delsym extended release, adults | 60 mg every 12 hours | No more than 120 mg in 24 hours |
| Children under 4 | Do not use | OTC cough and cold medicines are not for young children |
Dextromethorphan side effects and risks
Common side effects at label doses include dizziness, drowsiness, and nausea.[1]
High doses: large amounts cause dissociation, hallucinations, confusion, loss of coordination, fast heartbeat, high blood pressure, and psychosis.[3]
Other ingredients: taking high doses of combination products can cause acetaminophen liver failure or, with Coricidin's chlorpheniramine, seizures and heart problems.[3]
Genetics: about 7% of people of European descent are poor CYP2D6 metabolizers and can have much stronger, longer effects.
Dextromethorphan interactions: what not to mix with it
Choose what it would be combined with:
| Combined with | What happens | Guidance |
|---|---|---|
| MAO inhibitors (within 14 days) | Serotonin syndrome, high fever, death | Contraindicated |
| SSRIs, SNRIs, tramadol, triptans | Serotonin syndrome | Use caution |
| Fluoxetine, paroxetine, bupropion, quinidine (CYP2D6 inhibitors) | Much higher dextromethorphan levels | Use caution |
| Alcohol, opioids, sedatives | More sedation and impairment | Avoid |
| Ketamine or other dissociatives | Profound confusion and unconsciousness | Dangerous |
This is not a full list. A pharmacist can check a complete medication list, including supplements and over-the-counter products.[1]
Dextromethorphan overdose: signs and what to do
Overdose causes agitation, hallucinations, dissociation, fast heartbeat, high blood pressure, high temperature, vomiting, and, with serotonergic drugs, serotonin syndrome. Products with acetaminophen can cause delayed liver failure.[3]
If someone is having a dangerous reaction
- Call 911 for a seizure, chest pain, a very high temperature, trouble breathing, unresponsiveness, or if the person may harm themselves or others.
- Move them to a quiet, safe place away from roads, water, heights, and crowds. Stay with them and speak calmly.
- Do not leave the person alone and do not give them other drugs or alcohol to calm them down.
- If they become unresponsive, place them on their side and give naloxone in case opioids are involved.
Is dextromethorphan addictive?
Label doses are not addictive. People who repeatedly take high doses can develop tolerance, cravings, and compulsive use.[3]
- Days 1 to 3Come-downLow mood, fatigue, insomnia, and restlessness after heavy use.
- Week 1WithdrawalCravings, irritability, and poor concentration.
- WeeksRecoverySymptoms ease; memory and mood problems may linger after long-term heavy use.
How do you buy dextromethorphan safely in the US?
Dextromethorphan is sold over the counter. It is not a federal controlled substance.
- Age limits: about 20 states, including California, Florida, New York, and Texas, ban sales to anyone under 18 without a prescription, and many retailers check ID nationwide.
- Prescription forms: Auvelity and Nuedexta require a prescription.
- Cost: generic OTC dextromethorphan is inexpensive.
- Ask a pharmacist: a pharmacist can check whether it is safe with your other medicines and health conditions.
Can you buy dextromethorphan online?
Yes, from regular retailers, though many require age verification. Avoid buying bulk dextromethorphan powder, which is easy to overdose on.
The FDA's BeSafeRx tool explains how to recognize a safe online pharmacy.[4]
Dextromethorphan legal status in other countries
| Country | Status |
|---|---|
| United Kingdom | Pharmacy medicine |
| Canada | Non-prescription medicine |
| International | Not under UN control |
Laws change and differ in detail. Check current rules before carrying any controlled medicine across a border.[5]
Common questions about dextromethorphan
What is robotripping?
Taking very high doses of DXM cough medicine to get a dissociative high. It can cause psychosis and dangerous poisoning.
Can you take DXM with an antidepressant?
Not with MAO inhibitors, and only with caution with SSRIs and SNRIs because of serotonin syndrome.
Why do I need ID to buy cough medicine?
Many states ban sales of DXM to people under 18 to reduce teen misuse.
Is dextromethorphan an opioid?
No. It is chemically related to opioids but does not act on opioid receptors at normal doses.
What is Auvelity?
A prescription combination of dextromethorphan and bupropion approved in 2022 for major depression.
Sources
- Delsym (dextromethorphan) prescription information. DailyMed, US National Library of Medicine.
- Auvelity (dextromethorphan and bupropion) prescription information. DailyMed, US National Library of Medicine.
- Over-the-Counter Medicines DrugFacts. National Institute on Drug Abuse.
- BeSafeRx: Your Source for Online Pharmacy Information. US Food and Drug Administration.
- International drug control conventions. United Nations Office on Drugs and Crime.
