Meta Information
ID:dextromethorphan
Name:
Schema Version:AIM-2.0
Interactions
Target id:
/class/maois
Target name:
Monoamine Oxidase Inhibitors (MAOIs)
Severity:
major
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
null
Description:
Combining dextromethorphan with MAOIs can cause serotonin syndrome, a potentially life-threatening condition characterized by high fever, agitation, and muscle rigidity.
Actionable advice:
Do not take dextromethorphan if you are taking an MAOI or have taken one within the last 14 days.
Target id:
/class/serotonergic-agents
Target name:
Serotonergic Medications (SSRIs, SNRIs, TCAs, Triptans)
Severity:
major
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
null
Description:
Dextromethorphan has weak serotonin reuptake inhibiting properties, which can add to the effects of other serotonergic drugs, increasing the risk of serotonin syndrome.
Actionable advice:
Avoid using dextromethorphan with other serotonergic medications unless specifically directed by a physician.
Target id:
/class/cyp2d6-inhibitors
Target name:
CYP2D6 Inhibitors
Severity:
major
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
null
Description:
These drugs block the primary enzyme (CYP2D6) that metabolizes dextromethorphan, leading to significantly elevated drug levels and a high risk of side effects like hallucinations and agitation.
Actionable advice:
Avoid taking dextromethorphan with strong or moderate CYP2D6 inhibitors (e.g., bupropion, fluoxetine, paroxetine, quinidine).
Target id:
/class/cns-depressants
Target name:
CNS Depressants
Severity:
major
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
null
Description:
Dextromethorphan can cause drowsiness and dizziness, and combining it with other CNS depressants like alcohol, benzodiazepines, or opioids can lead to excessive sedation and respiratory depression.
Actionable advice:
Avoid combining dextromethorphan with any other substances that cause drowsiness or sedation.
Target id:
/dietary/alcohol-acute
Target name:
Alcohol
Severity:
major
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
null
Description:
Alcohol significantly enhances the sedative and dizzying effects of dextromethorphan, increasing the risk of accidents and respiratory depression.
Actionable advice:
Do not consume alcohol while taking dextromethorphan.
Target id:
/intervention/methylene-blue
Target name:
Methylene Blue
Severity:
major
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
null
Description:
Methylene blue is a potent, reversible MAOI. Co-administration with dextromethorphan, a serotonergic agent, creates a very high risk of life-threatening serotonin syndrome.
Actionable advice:
Do not take dextromethorphan if you are being treated with methylene blue.
Target id:
/intervention/linezolid
Target name:
Linezolid
Severity:
major
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
null
Description:
The antibiotic linezolid is a weak, reversible MAOI. Taking it with dextromethorphan poses a significant risk of developing serotonin syndrome.
Actionable advice:
Avoid taking dextromethorphan while on linezolid therapy and for two weeks after stopping.
Target id:
/condition/cyp2d6-poor-metabolizer
Target name:
CYP2D6 Poor Metabolizer Genetic Status
Severity:
major
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
null
Description:
Individuals with this genetic trait cannot effectively metabolize dextromethorphan, leading to very high drug levels and a significantly increased risk of adverse effects even at standard doses.
Actionable advice:
If you are a known CYP2D6 poor metabolizer, avoid dextromethorphan or use it only under strict medical supervision.
Target id:
/class/cyp3a4-strong-inhibitors
Target name:
Strong CYP3A4 Inhibitors
Severity:
moderate
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
null
Description:
These drugs block a secondary enzyme (CYP3A4) involved in dextromethorphan metabolism, which can increase its concentration and the risk of side effects.
Actionable advice:
Use with caution and monitor for side effects when combining with strong CYP3A4 inhibitors (e.g., ketoconazole, clarithromycin).
Target id:
/dietary/grapefruit-pomelo
Target name:
Grapefruit or Grapefruit Juice
Severity:
moderate
Interaction type:
adverse
Nature:
temporal
Temporal spacing:
Hours before target:
24
Hours after target:
24
Description:
Grapefruit contains compounds that inhibit the CYP3A4 enzyme in the gut, which can increase the absorption and blood levels of dextromethorphan.
Actionable advice:
Avoid consuming grapefruit or its juice for 24 hours before and after taking dextromethorphan.
Target id:
/class/cyp2d6-inducers
Target name:
CYP2D6 Inducers
Severity:
moderate
Interaction type:
diminishing
Nature:
absolute
Temporal spacing:
null
Description:
These drugs speed up the metabolism of dextromethorphan via the CYP2D6 enzyme, which may reduce its effectiveness as a cough suppressant.
Actionable advice:
Be aware that the cough-suppressant effect of dextromethorphan may be reduced if taken with CYP2D6 inducers.
Target id:
/class/broad-spectrum-inducers
Target name:
Broad-Spectrum Metabolic Enzyme Inducers
Severity:
moderate
Interaction type:
diminishing
Nature:
absolute
Temporal spacing:
null
Description:
Drugs like rifampin or St. John's Wort can accelerate the breakdown of dextromethorphan through the CYP3A4 pathway, potentially lowering its effectiveness.
Actionable advice:
Monitor for reduced cough suppression if taking dextromethorphan with strong enzyme inducers.
Target id:
/condition/hepatic-impairment
Target name:
Liver Disease (Hepatic Impairment)
Severity:
moderate
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
null
Description:
Since dextromethorphan is extensively metabolized by the liver, impaired liver function can lead to higher drug levels and an increased risk of toxicity.
Actionable advice:
Consult a physician before using dextromethorphan if you have liver disease; a dose reduction may be necessary.
Target id:
/condition/asthma-copd
Target name:
Chronic Respiratory Conditions (e.g., Asthma, COPD)
Severity:
moderate
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
null
Description:
Suppressing a productive cough in conditions like chronic bronchitis or asthma can lead to retained secretions and worsening of the underlying condition. High doses can also cause respiratory depression.
Actionable advice:
Consult a doctor before using dextromethorphan if you have a chronic cough associated with a respiratory disease.
Target id:
/intervention/memantine
Target name:
Memantine
Severity:
moderate
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
null
Description:
Both dextromethorphan and memantine are NMDA receptor antagonists; using them together may increase the risk of CNS side effects such as dizziness, confusion, and hallucinations.
Actionable advice:
Use this combination with caution and under medical guidance, monitoring for increased CNS side effects.
Target id:
/intervention/cannabis
Target name:
Cannabis (Marijuana)
Severity:
moderate
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
null
Description:
Both cannabis and dextromethorphan can cause drowsiness, dizziness, and impaired coordination. Using them together can potentiate these CNS depressant effects.
Actionable advice:
Avoid using cannabis while taking dextromethorphan to prevent excessive sedation and impairment.
Target id:
/condition/pediatric
Target name:
Pediatric Population (especially under 4 years)
Severity:
major
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
null
Description:
The safety and efficacy of dextromethorphan in young children are not well established, and they may be more susceptible to adverse effects like hallucinations and respiratory depression.
Actionable advice:
Do not give dextromethorphan-containing products to children under 4 years of age; consult a pediatrician for older children.
Target id:
/condition/lactation
Target name:
Breastfeeding (Lactation)
Severity:
moderate
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
null
Description:
It is not known if dextromethorphan passes into breast milk, but due to potential sedative effects on the infant, its use is generally discouraged.
Actionable advice:
Consult a healthcare provider before using dextromethorphan while breastfeeding.
Target id:
/condition/pregnancy
Target name:
Pregnancy
Severity:
minor
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
null
Description:
While some studies suggest dextromethorphan is likely safe during pregnancy, it should only be used if the potential benefit justifies the potential, though small, risk to the fetus.
Actionable advice:
Consult your doctor before using dextromethorphan during pregnancy.