Dextromethorphan (Delsym) Dosing Guidelines
The recommended dosing for Delsym (dextromethorphan polistirex) is 10 mL every 12 hours for adults and children 12 years and older, 5 mL every 12 hours for children 6-11 years, and 2.5 mL every 12 hours for children 4-5 years, with Delsym not recommended for children under 4 years of age. 1
Age-Based Dosing
Delsym contains dextromethorphan in an extended-release polistirex formulation that provides 12-hour cough relief. The FDA-approved dosing is as follows:
- Adults and children ≥12 years: 10 mL every 12 hours (not to exceed 20 mL in 24 hours)
- Children 6 to <12 years: 5 mL every 12 hours (not to exceed 10 mL in 24 hours)
- Children 4 to <6 years: 2.5 mL every 12 hours (not to exceed 5 mL in 24 hours)
- Children <4 years: Do not use 1
Important Administration Guidelines
- Shake the bottle well before use
- Measure only with the dosing cup provided with the medication
- Do not use the Delsym dosing cup with other products
- Administer as directed or as prescribed by a physician 1
Clinical Considerations
Extended-Release Formulation
Delsym contains dextromethorphan polistirex, which is an extended-release formulation with a duration of action approximately 2-3 times longer than standard dextromethorphan hydrobromide formulations. The polistirex binder slows the release of the active ingredient, providing 12-hour coverage versus the 4-6 hour coverage of immediate-release formulations. 2
Safety Considerations
Overdose Risk: Dextromethorphan polistirex overdose can be serious due to its extended-release properties. A case report documented life-threatening symptoms in a toddler with a blood concentration exceeding 100 ng/mL. 2
Recreational Abuse: Be aware of the potential for dextromethorphan abuse, particularly in adolescents and young adults. At supratherapeutic doses, it can produce dissociative effects through NMDA receptor antagonism. 3, 4
Drug Interactions: Dextromethorphan is metabolized by CYP2D6 and can interact with inhibitors of this enzyme (such as quinidine), potentially increasing dextromethorphan plasma concentrations. 5
Dose-Response Relationship
Research suggests that weight-based dosing of approximately 0.5 mg/kg may provide optimal balance between symptomatic relief and avoiding adverse events, though current FDA-approved dosing is based on age rather than weight. 6
Monitoring
- Monitor for adverse effects including dizziness, drowsiness, and gastrointestinal symptoms
- For children, ensure parents understand proper dosing with the provided measuring device to prevent overdose
- In patients taking other medications, assess for potential drug interactions before recommending dextromethorphan
Remember that while dextromethorphan is widely used for cough suppression, its efficacy for treating acute cough in children has been questioned by some medical authorities. 6