Does Furosemide Benzalkonium Chloride Interact with Phenytoin?
Furosemide Benzalkonium Chloride and Phenytoin have a moderate drug interaction according to U.S. FDA drug labeling data. Phenytoin interferes directly with renal action of furosemide and decreases intestinal absorption, leading to lower peak serum furosemide concentrations. The mechanism involves decreased absorption and renal action of furosemide. 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
- Moderate
- Phenytoin Class
- Anti-epileptic Agent
- Management
- Monitor for effects
- Data Source
- U.S. FDA via OpenFDA
How This Interaction Works
The interaction between Furosemide Benzalkonium Chloride and Phenytoin occurs because decreased absorption and renal action of furosemide. Clinically, this means phenytoin interferes directly with renal action of furosemide and decreases intestinal absorption, leading to lower peak serum furosemide concentrations. This is classified as a moderate interaction. While it may not require stopping either medication, your healthcare provider should be aware you are taking both so they can monitor for potential effects and adjust treatment if necessary.
What To Tell Your Doctor or Pharmacist
If you are taking Furosemide Benzalkonium Chloride and your doctor is considering prescribing Phenytoin (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