Dextromethorphan is the Most Problematic Component Due to Abuse Potential
Among the three components, dextromethorphan carries the highest risk for abuse and dependency, particularly in adolescents and young adults who intentionally consume megadoses (5-10 times the therapeutic dose) to achieve dissociative and hallucinogenic effects similar to phencyclidine (PCP). 1, 2
Abuse Potential and Mechanisms
Dextromethorphan Abuse Profile
Dextromethorphan produces profound psychological and physiological effects at megadoses, acting through the NMDA receptor system to create dissociative and sedative properties similar to PCP. 2, 3
Adolescents specifically target dextromethorphan because it is legal, inexpensive, easily accessible through over-the-counter purchase or shoplifting, and widely available online as pure powder in gram quantities. 2
The drug can cause addiction mediated through the NMDA system, with documented cases of dextromethorphan use disorder characterized by intense cravings and failed abstinence attempts. 3
Acute megadoses can produce psychotic symptoms including psychotic mania, requiring psychiatric intervention. 4
Prevalence and Trends
Despite mitigation efforts, dextromethorphan abuse remains a documented problem, though annual prevalence among 8th, 10th, and 12th graders decreased 35% between 2010-2015 following targeted abuse prevention programs. 1
The FDA held an Advisory Committee meeting in 2010 specifically to evaluate dextromethorphan's abuse potential and whether it should be scheduled under the Controlled Substances Act. 1
Comparison with Other Components
Chlorpheniramine Maleate
Chlorpheniramine is a first-generation sedating antihistamine that causes drowsiness but lacks significant abuse or dependency potential. 5
Its primary concern is sedation, not abuse, making it problematic for daytime functioning but not for dependency. 5
Phenylephrine
Phenylephrine is a decongestant with no documented abuse or dependency potential in the medical literature.
It carries cardiovascular risks (hypertension, tachycardia) but not addiction risk. 5
Clinical Recognition and Pitfalls
Key Warning Signs
Approximately 5% of persons of European ethnicity lack normal CYP2D6 metabolism capacity, leading to rapid accumulation of toxic dextromethorphan levels even at lower doses. 2
Dextromethorphan megadoses can produce false-positive urine screening tests for phencyclidine, potentially confusing clinical assessment. 2
Combination Product Risks
When dextromethorphan is abused in combination products containing acetaminophen, chlorpheniramine maleate, guaifenesin, or pseudoephedrine, toxicity is additive and potentially more severe than dextromethorphan alone. 2
Adolescents access extraction procedures online to isolate concentrated dextromethorphan powder from combination tablets (street name "triple C" for Coricidin HBP Cough & Cold). 2
Regulatory Context
Despite documented abuse potential, the FDA ultimately did not recommend controlled substance scheduling for dextromethorphan, determining that targeted abuse mitigation strategies were more appropriate than restricting legitimate medical access. 1
The benefits of dextromethorphan for legitimate cough suppression were deemed to far outweigh its abuse risks when appropriate interventions are implemented. 1