Does Ritonavir Interact with Promethazine Phenylephrine Codeine?
Ritonavir and Promethazine Phenylephrine Codeine have a major drug interaction according to U.S. FDA drug labeling data. ketoconazole), or protease inhibitors (e.g., ritonavir), may result in an increase in codeine plasma concentrations with subsequently greater metabolism by cytochrome CYP2D6, resulting in greater morphine levels, which could increase or prolong adverse reactions and may cause potentially fatal respiratory depression, particularly when an inhibitor is added after a stable dose of Promethazine and Phenylephrine HCl and Codeine Phosphate Oral Solution is achieved [see Warnings and Precautions (5.9) ] . 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
- Major
- Ritonavir Class
- Cytochrome P450 3A Inhibitor
- Management
- Close medical supervision required
- Data Source
- U.S. FDA via OpenFDA
What To Tell Your Doctor or Pharmacist
If you are taking Ritonavir and your doctor is considering prescribing Promethazine Phenylephrine Codeine (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 how frequently you should be monitored while these are co-prescribed
- Ask whether any dosage adjustments are needed
- Never stop or change either medication without first consulting your healthcare provider