Dextromethorphan Dosage Guide

The danger of DXM overdose depends critically on what was consumed. An overdose on DXM-only products is medically serious but rarely fatal in otherwise healthy individuals. An overdose involving acetaminophen-containing products is a medical emergency that can cause irreversible liver failure and death. ## Recognizing DXM Overdose - Extreme agitation, delirium, or unresponsiveness - Very rapid heartbeat (tachycardia above 150 bpm sustained) - High blood pressure - Dangerously elevated body temperature (hyperthermia) - Seizures - Muscle rigidity (suggesting serotonin syndrome) - Severely impaired or absent breathing (at extreme doses) - Nystagmus (rapid involuntary eye movements) ## The Acetaminophen Emergency If there is any possibility that the ingested product contained acetaminophen, call 911 immediately regardless of how the person appears. Acetaminophen liver toxicity is insidious: the person may feel relatively fine for 24-48 hours while irreversible liver damage progresses. N-acetylcysteine (NAC) is an effective antidote but is most effective within 8 hours of ingestion. Inform emergency responders specifically that acetaminophen may have been co-ingested. ## Serotonin Syndrome If the person is on SSRIs, SNRIs, MAOIs, or has combined DXM with MDMA or tramadol, watch for: muscle rigidity, clonus (rhythmic muscle jerking), hyperthermia, rapid heartbeat, agitation, and confusion. This is serotonin syndrome and requires emergency treatment. Cyproheptadine is the specific antidote used in emergency settings. ## Emergency Response 1. Call 911. Be honest about what was consumed -- medical staff need accurate information, and Good Samaritan laws protect callers in most jurisdictions 2. If the person is unconscious, place them in the recovery position (on their side) to prevent aspiration of vomit 3. If they are seizing, protect their head but do not restrain them or put anything in their mouth 4. If breathing is absent or very slow, begin CPR 5. Monitor body temperature -- DXM overdose can cause dangerous hyperthermia 6. Do not leave the person alone ## When to Call 911 Call emergency services if any of the following are present: seizures, unresponsiveness, sustained heart rate above 150 bpm, chest pain, very high body temperature, signs of serotonin syndrome, severely slowed breathing, or any suspicion of acetaminophen co-ingestion.