Dexamethasone Ophthalmic and Meperidine: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Meperidine
Dexamethasone Ophthalmic
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
Reduced meperidine exposure and reduced efficacy of meperidine
Interaction Deep Dive
Concomitant use of meperidine with any CYP3A4 inducer may result in reduced meperidine exposure, reducing efficacy and may lead to opioid withdrawal symptoms in patients physically dependent on meperidine. In a drug interaction study, the hepatic metabolism of meperidine may be enhanced by phenytoin (CYP3A4 inducer). Concomitant administration resulted in reduced half-life and bioavailability with increased clearance of meperidine in healthy subjects; however, blood concentrations of normeperidine were increased. If concomitant use is needed, closely monitor patients for reduced efficacy or signs of opioid withdrawal syndrome, and consider increasing the dose of meperidine as necessary. If a CYP3A4 inducer is being discontinued, consider meperidine dose reduction and closely monitor patients for signs of respiratory depression or sedation12.
Why it happens (mechanism)
Induction of CYP3A4-mediated metabolism of meperidine
Literature reports
2 reports — tap to read
a) Following administration of meperidine in the presence of phenytoin, meperidine's systemic clearance was significantly increased, half-life and bioavailability decreased, and plasma levels of its active metabolite, normeperidine (weak analgesic activity) was elevated in a clinical study of 4 nonsmoking, healthy men aged 23 to 26 years. Meperidine 50 mg IV and 100 mg orally were administered 48 hours apart, before, during, and 3 weeks after phenytoin for 10 days. Meperidine clearance in the presence of phenytoin significantly rose from 1017 +/- 225 to 1280 +/- 130 mL/min, elimination half-life significantly fell from 6.4 +/- 1 to 4.3 +/- 0.4 hour, and bioavailability fell (although not significant) from 0.61 +/- 0.08 to 0.43 +/- 0.14. Normeperidine AUC (0 to 24 hours) following IV meperidine significantly rose from 385 +/- 105 to 589 +/- 108 nanogram/hr/mL. Following oral meperidine with concomitant phenytoin, there was a nonsignificant increase in normeperidine AUC in every subject. Due to extensive first-pass metabolism, a larger oral than IV dose of meperidine is required for equianalgesic activity and the larger oral doses may be associated with greater normeperidine toxicity. Therefore, IV meperidine is preferred over oral meperidine in patients on long-term phenytoin therapy 3.
b) In a drug interaction study, the hepatic metabolism of meperidine may be enhanced by phenytoin (CYP3A4 inducer). Concomitant administration resulted in reduced half-life and bioavailability with increased clearance of meperidine in healthy subjects; however, blood concentrations of normeperidine were increased 12.
Common questions
Can I take Dexamethasone Ophthalmic and Meperidine together?
Reduced meperidine exposure and reduced efficacy of meperidine Always confirm with your pharmacist or prescriber before making any change.
How serious is the Dexamethasone Ophthalmic and Meperidine interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How strong is the evidence for this interaction?
The evidence is graded "probable". Good supporting evidence, though not definitively proven.
Questions for your pharmacist
- Does my dose of Dexamethasone Ophthalmic or Meperidine need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there a safer alternative to one of these medications for me?
References (3)
- Product Information: MEPERGAN intramuscular, intravenous injection, meperidine HCl, promethazine HCl intramuscular, intravenous injection. West-Ward Pharmaceuticals Corp (per FDA), Eatontown, NJ, 2023.
- Product Information: DEMEROL(R) oral tablets, oral solution, meperidine HCl oral tablets, oral solution. Validus Pharmaceuticals LLC (per FDA), Parsippany, NJ, 2023. DailyMed
- Pond SM & Kretschzmar KM: Effect of phenytoin on meperidine clearance and normeperidine formation. Clin Pharmacol Ther 1981; 30:680-686. PubMed
Keep reading about Meperidine
Keep reading about Dexamethasone Ophthalmic
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