What is the recommended dosing for Robotussin (dextromethorphan)

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Last updated: November 24, 2025View editorial policy

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Robitussin (Dextromethorphan) Dosing

For adults, dextromethorphan is typically dosed at 20 mg every 4-6 hours for cough suppression, with this dose demonstrating effective antitussive activity in clinical trials. 1

Adult Dosing

  • Standard dose: 20 mg every 4-6 hours as needed for cough suppression 1
  • This dosing has been validated in controlled trials comparing dextromethorphan to codeine, showing similar efficacy in reducing cough frequency 1
  • Dextromethorphan at 20 mg demonstrated superior reduction in cough intensity compared to codeine at the same dose (p < 0.0008) 1

Pediatric Dosing

Specific pediatric dosing for dextromethorphan is not well-established in the provided guidelines. The American Academy of Pediatrics drug formularies reviewed do not include specific dextromethorphan dosing recommendations. 2

  • For pediatric patients, weight-based and age-specific factors must be considered when determining appropriate dosing 3
  • Consultation with current product labeling or a pediatric pharmacist is recommended for children

Safety Profile

  • Dextromethorphan has a reassuring safety profile with infrequent and usually non-severe adverse reactions 4
  • Adverse effects are typically dose-related and include neurological, cardiovascular, and gastrointestinal disturbances 4
  • The drug is safe even in overdose situations 1
  • It lacks the CNS side effects of opiates including respiratory depression, abuse liability (in therapeutic use), and analgesic properties 5

Critical Drug Interactions

Avoid concurrent use with monoamine oxidase inhibitors (MAOIs) - this represents the most significant safety concern with dextromethorphan. 4

Abuse Potential

  • Chronic abuse represents the most significant hazard identified through adverse event reporting 4
  • Recurrent high-dose use can lead to bromism (chronic bromide toxicity) when using bromide-containing formulations like Robitussin HBr, manifesting as hyperchloremia and decreased anion gap 6
  • Patients presenting with repeated overdoses should be evaluated for substance abuse 6

Clinical Advantages

  • Non-narcotic status makes it preferable to codeine in many clinical situations 1
  • No prescription required for over-the-counter formulations 4
  • Well-tolerated with over 30 years of clinical experience 4

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Guideline

Simethicone Dosing for Gastrointestinal Procedures

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Research

Bromism: An overlooked and elusive toxidrome from chronic dextromethorphan abuse.

The American journal of emergency medicine, 2020

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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