What is the risk of withdrawal from daily dextromethorphan (cough suppressant) use?

Risk of Withdrawal from Daily Dextromethorphan Use

Daily dextromethorphan use can lead to physical dependence and withdrawal symptoms, particularly at higher doses and with prolonged use. While dextromethorphan (DM) is widely available as an over-the-counter cough suppressant, its chronic use carries significant risks that are often underrecognized by healthcare providers.

Evidence of Dextromethorphan Dependence and Withdrawal

Research has documented cases of dextromethorphan dependence and withdrawal syndrome:

• A documented case of a 44-year-old man who became dependent on dextromethorphan after six years of regular use at doses up to 1800 mg daily. During inpatient detoxification, he developed a vegetative withdrawal syndrome consisting of craving, diaphoresis, nausea, hypertension, and tachycardia 1.

• Another case report described cognitive deterioration resulting from prolonged dextromethorphan abuse 2.

• Dextromethorphan has specific serotonergic and sigma-1 opioidergic properties, while its active metabolite dextrorphan (DOR) is a stronger NMDA receptor antagonist. These pharmacological properties contribute to its addiction potential 3.

Withdrawal Symptoms

When discontinuing daily dextromethorphan use, patients may experience:

• Craving for the substance
• Autonomic symptoms (diaphoresis, hypertension, tachycardia)
• Gastrointestinal disturbances (nausea)
• Psychological symptoms (anxiety, irritability)
• Cognitive effects (difficulty concentrating)

Risk Factors for More Severe Withdrawal

The severity of withdrawal symptoms appears to correlate with:

1. Dose: Higher daily doses (particularly recreational doses exceeding therapeutic recommendations) increase risk
2. Duration of use: Longer periods of regular use (months to years) increase risk
3. Individual factors: Personal susceptibility to substance dependence

Management Approach for Discontinuation

For patients who have been using dextromethorphan daily and wish to discontinue:

1. Gradual tapering is recommended rather than abrupt cessation

   • Similar to other substances with withdrawal potential, a reduction of approximately 25% every 5-7 days may be appropriate
   • For long-term, high-dose users, an even more gradual taper over 4-8 weeks should be considered

2. Monitoring for withdrawal symptoms

   • Vital signs (blood pressure, heart rate)
   • Psychological symptoms
   • Cravings

3. Supportive care

   • Hydration
   • Symptomatic management of specific withdrawal symptoms

Clinical Implications

Healthcare providers should be aware that dextromethorphan, despite being available over-the-counter, carries a potential for dependence and withdrawal. This is particularly important when:

• Evaluating patients with unexplained autonomic symptoms
• Assessing patients with a history of substance use disorders
• Treating patients who report regular use of cough medications

Prevention

To prevent dextromethorphan dependence:

• Limit use to recommended therapeutic doses and durations
• Screen for history of substance use disorders before recommending even short-term use
• Consider alternative cough suppressants for patients with risk factors for substance dependence

The evidence suggests that dextromethorphan should be recognized as a psychotropic substance with potential for abuse, dependence, and withdrawal, despite its over-the-counter availability 1, 3.