Does Barbiturates Interact with Promethazine Hydrochloride And Phenylephrine Hydrochloride?
Moderate interaction. Promethazine may increase, prolong, or intensify sedative action; dose of barbiturates should be reduced by at least one-half.
Source & how this summary was prepared
This interaction summary was extracted from FDA drug labeling through openFDA, using automated processing and AI assistance. NIH/NLM RxNorm helps organize drug names.
Read the saved source label on DailyMed →
A separate current-label comparison has not been recorded for this page. Read about our extraction process.
- Interaction classification
- Moderate
- Management
- Confirm exact products with your pharmacist
- Data Source
- U.S. FDA via OpenFDA
How this interaction works
CNS depression potentiation
What To Tell Your Doctor or Pharmacist
If you are taking Barbiturates and your doctor is considering prescribing Promethazine Hydrochloride And Phenylephrine Hydrochloride (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 whether any dosage adjustments are needed
- Never stop or change either medication without first consulting your healthcare provider