What is the indication for dextromethorphan (DXM)?

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Last updated: May 8, 2025View editorial policy

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From the Guidelines

Dextromethorphan is indicated for the symptomatic treatment of cough, particularly in patients with lung cancer, as an initial approach due to its low cost, some evidence of effect, and low side effect profile 1.

Key Points

  • The typical adult dose of dextromethorphan is 10-15 mg tid or qid, with a maximum dose of 120 mg/d 1.
  • Dextromethorphan is available in various over-the-counter formulations, including syrups, lozenges, and tablets, often combined with other medications like antihistamines or decongestants.
  • It's essential to note that dextromethorphan is not effective for productive coughs and should not be used for chronic coughs or coughs associated with smoking, asthma, emphysema, or when cough is accompanied by excessive secretions.
  • Patients should be cautious about potential interactions with MAO inhibitors and certain antidepressants, which can lead to serotonin syndrome.
  • Side effects are generally mild at therapeutic doses and may include drowsiness, dizziness, or gastrointestinal disturbances.

Clinical Considerations

  • In patients with lung cancer, opioids such as codeine, hydrocodone, and dihydrocodeine may be considered if dextromethorphan is not effective 1.
  • Local anesthetics like nebulized lidocaine may be tried when other pharmacologic approaches have failed to manage cough among patients with lung cancer 1.
  • The choice of treatment may be dictated primarily by availability rather than pharmacologic parameters in many countries.

Evidence Summary

  • A study published in Chest in 2017 suggests that dextromethorphan may be used as an initial approach for cough treatment in patients with lung cancer due to its low cost and low side effect profile 1.
  • Another study published in Chest in 2006 found that opioids such as hydrocodone and dihydrocodeine are effective in suppressing cough in patients with lung cancer 1.
  • A study published in the European Respiratory Journal in 2005 found that dextromethorphan showed some effect in patients with acute cough, whereas studies on codeine in the same patients failed to show beneficial effects 1.

From the FDA Drug Label

Package/Label Principal Display Panel Compare to Delsym® active ingredient Dextromethorphan Polistirex Extended-Release Oral Suspension Cough Suppressant The indication for dextramorphan is cough suppression 2.

  • The drug is used for 12 Hour Cough Relief
  • It is a cough suppressant The dosage is provided for different age groups, but the primary use is for relieving cough 2.

From the Research

Indications for Dextramorphan

  • Dextromethorphan is indicated for the treatment of cough associated with acute upper respiratory tract infection 3, 4
  • It is also used as an antitussive for the treatment of chronic cough in adults 5
  • Additionally, dextromethorphan has been repurposed as a treatment for pseudobulbar affect and major depressive disorder 6
  • The medication has been shown to attenuate capsaicin-induced cough in healthy volunteers, demonstrating its broad activity on the cough reflex 7

Specific Uses

  • Treatment of cough in children aged 6-11 years with acute cough due to the common cold 3
  • Treatment of cough associated with acute upper respiratory tract infection in adults 4
  • Treatment of chronic cough in adults, with demonstrated efficacy compared to placebo 5
  • Treatment of pseudobulbar affect and major depressive disorder, often in combination with other medications 6

Mechanism of Action

  • Dextromethorphan works as an antitussive by reducing the frequency and severity of coughing 3, 4, 5
  • Its exact mechanism of action is not fully understood, but it is thought to involve the inhibition of cough receptors in the brain and lungs 7

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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