Can a Patient Take Dextromethorphan with Eliquis, Metoprolol, Atorvastatin, and Levothyroxine?
Yes, dextromethorphan can generally be taken with this medication regimen, as there are no clinically significant direct drug-drug interactions between dextromethorphan and any of these four medications. 1
Key Safety Considerations
No Major Pharmacokinetic Interactions
Dextromethorphan does not interact with apixaban (Eliquis), as apixaban is metabolized primarily through CYP3A4 and P-glycoprotein pathways, while dextromethorphan is metabolized by CYP2D6 and does not significantly affect these pathways 2
Metoprolol and dextromethorphan share CYP2D6 metabolism, but dextromethorphan does not inhibit this enzyme and therefore does not increase metoprolol levels or beta-blockade effects 3
Atorvastatin is metabolized by CYP3A4 and has no interaction with dextromethorphan, which is a CYP2D6 substrate 4, 1
Levothyroxine absorption can be affected by bile acid sequestrants but has no interaction with dextromethorphan 4
Critical Contraindications to Rule Out
The most important safety concern is ensuring the patient is NOT taking monoamine oxidase inhibitors (MAOIs) or selective serotonin reuptake inhibitors (SSRIs), as these can cause life-threatening serotonin syndrome when combined with dextromethorphan. 5
If the patient is taking MAOIs or SSRIs with dextromethorphan, poison center follow-up every 2 hours for 8 hours is recommended 5
Monitor for serotonin syndrome symptoms: hyperthermia (>104°F), altered mental status, muscle rigidity, and autonomic instability 5
Dosing and Monitoring Recommendations
Safe Dextromethorphan Use
Use standard over-the-counter doses (typically 10-20 mg every 4 hours or 30 mg every 6-8 hours for adults) 1
Dextromethorphan has an excellent safety profile when used at therapeutic doses, with adverse reactions being infrequent and usually not severe 1
Doses above 7.5 mg/kg require emergency department evaluation 5
Monitoring the Existing Medication Regimen
The combination of apixaban with atorvastatin is safe, though be aware that adding strong P-glycoprotein inhibitors (like amiodarone or diltiazem) could increase apixaban levels 2
Metoprolol with atorvastatin has no significant interaction 4
Levothyroxine should be taken separately from any medications that could affect absorption, though this is not relevant for dextromethorphan 4
Common Pitfalls to Avoid
Do not assume all cough medications are safe: Many combination cough/cold products contain multiple active ingredients including acetaminophen, which would require separate risk assessment 5
Avoid in elderly patients with multiple CNS-active medications: The 2019 Beers Criteria caution against combining three or more CNS agents (including dextromethorphan if used chronically) due to increased fall risk 4
Watch for abuse potential: Dextromethorphan abuse is the most significant safety hazard identified in adverse event reporting, particularly in younger patients 1
Short-term use only: Dextromethorphan is intended for short-term symptomatic relief; prolonged use requires reassessment 1