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Does Promethazine Hydrochloride And Codeine Phosphate Interact with Ketoconazole?

Promethazine Hydrochloride And Codeine Phosphate and Ketoconazole have a contraindicated drug interaction according to U.S. FDA drug labeling data. CYP3A4 inhibitor may increase codeine plasma concentrations and morphine levels, potentially causing fatal respiratory depression. Avoid use; if necessary, monitor frequently. The mechanism involves inhibition of cyp3a4 increases codeine metabolism by cyp2d6, raising morphine levels. Patients taking both medications should consult their healthcare provider before starting, stopping, or changing the dosage of either drug. This information is based on official FDA drug labeling sourced from OpenFDA and the NIH National Library of Medicine.

Severity
Contraindicated
Ketoconazole Class
Azole Antifungal
Management
Do not take together
Data Source
U.S. FDA via OpenFDA

How This Interaction Works

The interaction between Promethazine Hydrochloride And Codeine Phosphate and Ketoconazole occurs because inhibition of cyp3a4 increases codeine metabolism by cyp2d6, raising morphine levels. Clinically, this means cyp3a4 inhibitor may increase codeine plasma concentrations and morphine levels, potentially causing fatal respiratory depression. avoid use; if necessary, monitor frequently. Because of the severity of this interaction, these medications are contraindicated — meaning they should not be taken together under any circumstances. If you are currently taking both, contact your healthcare provider immediately to discuss alternatives.

What To Tell Your Doctor or Pharmacist

If you are taking Promethazine Hydrochloride And Codeine Phosphate and your doctor is considering prescribing Ketoconazole (or vice versa), make sure to:

  • Inform your doctor and pharmacist of all current medications, including over-the-counter drugs and supplements
  • Ask whether the benefits of combining these medications outweigh the risks for your specific situation
  • Ask what symptoms to watch for that would indicate the interaction is causing problems
  • Ask about alternative medications that do not interact with your current regimen
  • Ask how frequently you should be monitored while these are co-prescribed
  • Never stop or change either medication without first consulting your healthcare provider
💊 Promethazine Hydrochloride And Codeine Phosphate(Promethazine Hydrochloride And Codeine Phosphate)+💊 Ketoconazole

Severity & Interaction Details

⛔
contraindicated
Avoid this combination
FDA labeling lists this pair as contraindicated. The risk outweighs the benefit in nearly all cases.
Severity scale
MinorContra
On record
Yes
Drug A class
—
Drug B class
Azole Antifungal
Source
NLP:promethazine hydrochloride and codeine phosphate

What this means in plain English

CYP3A4 inhibitor may increase codeine plasma concentrations and morphine levels, potentially causing fatal respiratory depression. Avoid use; if necessary, monitor frequently.

What the FDA label says

"Inhibition of CYP3A4 increases codeine metabolism by CYP2D6, raising morphine levels"

📖 Source: NLP:promethazine hydrochloride and codeine phosphate

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Data sourced from U.S. FDA drug labeling via openFDA and the NIH National Library of Medicine. For informational purposes only. Always consult your pharmacist or physician.