II. Background
- Dextromethorphan Abuse is increasing in United States (especially among teens)
- Intentional abuse terms include "Robo-Tripping" or "dexing"
- Common Dextromethorphan sources used for abuse
- Coricidin Cough and Cold ("skittles", Triple C with DM and Chlorpheniramine)
- Many other Coricidin products contain Acetaminophen (see precautions below)
- Extract Dextromethorphan from OTC preparations (Crystal-Dex)
- Pure Dextromethorphan as a "research chemical" via the internet
- Coricidin Cough and Cold ("skittles", Triple C with DM and Chlorpheniramine)
III. Mechanism
- Dextromethorphan has NMDA activity and serotonergic activity
IV. Signs
-
General
- Altered Level of Consciousness
- Does not typically cause respiratory depression
- Hyperthermia
- Diaphoresis
- Ocular changes (Mydriasis, Nystagmus)
- Sinus Tachycardia
- Neurologic changes (sedation, dysphoria, Dystonia, Hallucinations, rigidity, Seizures)
- Dose-Dependent Effects
- Typical Antitussive dose (20-30 mg every 4-6 hours)
- Cough Suppressant
- Adverse effects include Nausea, Vomiting, drowsiness, sedation and Agitation
- Low dose Overdose (100-200 mg)
- Mild euphoria
- Increased energy
- Ataxia on ambulation ("robo walk")
- High dose (adults >200-400 mg Dextromethorphan, child >2 mg/kg)
- Euphoria
- Auditory Hallucinations and Visual Hallucinations
- Higher dose (400 to 1000 mg Dextromethorphan)
- Partial dissociation
- Very high dose (1000 mg or 500 ml of 20 mg/10 ml Dextromethorphan)
- Complete dissociation
- Typical Antitussive dose (20-30 mg every 4-6 hours)
- Combination product abuse
- Acetaminophen Toxicity risk (see below)
- Anticholinergic Toxicity
- Combination products containing Diphenhydramine or Chlorpheniramine
V. Labs
- See Unknown Ingestion
- Bedside Glucose
-
Hyperchloremia and normal Anion Gap (or negative Anion Gap - a cation gap)
- Limited to Dextromethorphan preparations containing hydrobromide salt
- Results in falsely elevated Serum Chloride (due to bromide being read by analyzers as chloride)
-
Acetaminophen Level
- Elevated if combination product was abused
- Salicylate Level
-
Blood Alcohol Level
- Indicated in Altered Level of Consciousness
-
Liver Function Tests and INR
- Evaluate for chronic excessive Acetaminophen ingestions and secondary hepatotoxicity
VI. Precautions
-
Acetaminophen Toxicity risk
- Many Dextromethorphan products also contain Acetaminophen
-
Anticholinergic Toxicity risk
- Associated with combination agent Overdose containing Diphenhydramine
- "Cheese" (Heroin with Dextromethorphan and Diphenhydramine)
-
Serotonin Syndrome risk
- See below
- Avoid combining with other serotonergic agents (e.g. Zofran - use Haloperidol as alternative Antiemetic)
VII. Management
- Supportive care
- Naloxone is unlikely to have much effect unless there is respiratory depression
- Agitation Management
- Serotonin Syndrome management
- Hyperthermia Management
VIII. Course
- Short acting agents: 6 hours
- DextromethorphanHalf-Life: 2-4 hours
- May persist longer in poor metabolizers
- May discharge home if asymptomatic for 6 hours since ingestion
- Long acting agents (Delsym): 12 hours
IX. Complications
-
Serotonin Syndrome (when combined with other serotonergic agents)
- Dextromethorphan is a non-Selective Serotonin Reuptake Inhibitor
- At very high dose, Dextromethorphan alone could cause Serotonin Syndrome
- Observe for Clonus as a hallmark finding in Serotonin Syndrome
X. References
- Fontes (2014) Crit Dec Emerg Med 28(1): 14-24
- Nordt and Swadron in Majoewsky (2017) EM: RAP 17(9): 15
- Nordt and Swadron in Majoewsky (2012) EM: RAP 12(5): 3
- Tomaszewski (2019) Crit Dec Emerg Med 33(11):28