Dextromethorphan Dosage Guide

DXM overdose risks depend heavily on the formulation consumed. The most dangerous scenario involves products containing acetaminophen, which can cause irreversible liver failure at high doses. Overdose on DXM alone can cause serotonin syndrome (especially with serotonergic co-medications), tachycardia, hypertension, respiratory depression at extreme doses, seizures, and hyperthermia. Signs of DXM overdose include: extreme agitation or delirium, very rapid heartbeat, high blood pressure, seizures, high fever, muscle rigidity (serotonin syndrome), loss of consciousness, and very slow breathing (at extreme doses). If acetaminophen is involved, liver damage symptoms (abdominal pain, jaundice) may develop over 24-72 hours. Call emergency services (911) immediately. Inform them if acetaminophen was co-ingested, as N-acetylcysteine (NAC) is an effective antidote for acetaminophen toxicity but must be administered within hours. Cyproheptadine is used in the emergency setting for serotonin syndrome. Treatment is otherwise supportive, with monitoring for cardiac, respiratory, and temperature abnormalities. Good Samaritan laws apply. ## Community-Sourced Overdose and Emergency Information ### The Acetaminophen Emergency Community members cannot emphasize strongly enough that the **most dangerous DXM overdose scenario involves products containing acetaminophen**. Acetaminophen (paracetamol) can cause irreversible liver failure at doses well within the range a recreational DXM user might consume. If acetaminophen is co-ingested: - **Seek emergency medical attention immediately**, even if the person feels fine - Inform medical staff that acetaminophen was consumed, as the antidote **N-acetylcysteine (NAC)** is most effective when administered within 8 hours - Liver damage from acetaminophen may not produce symptoms for 24-72 hours, by which point it may be irreversible ### Managing Difficult Experiences Community recommendations for managing overwhelming DXM experiences include: - Move to a quiet, dark, comfortable environment - Listen to calming music - Reassure the person that the effects will pass (DXM experiences can last 6-10+ hours, which can feel extremely long during a difficult experience) - Keep the person hydrated - If nausea is severe, help the person to a comfortable position on their side to prevent aspiration - **Benzodiazepines** can help manage extreme anxiety if available ### When to Call Emergency Services Community consensus is to call emergency services if: - Acetaminophen or other dangerous active ingredients were consumed - The person has a seizure - The person has a very rapid heartbeat (above 150 bpm sustained) or chest pain - Body temperature appears dangerously high - Signs of serotonin syndrome (muscle rigidity, very high fever, agitation, rapid heartbeat) - The person is unresponsive and cannot be roused - The person combined DXM with SSRIs, MAOIs, or other serotonergic substances ### Extreme Dose Warnings Community discussions occasionally feature individuals planning or reporting extremely high DXM doses (1500+ mg). Community consensus is that such doses carry serious risk of medical emergency including seizures, serotonin toxicity, and cardiac complications. Users planning such doses are strongly urged to reconsider, as the additional intensity relative to a high third-plateau dose is marginal while the physical risks increase substantially.