Drug Interaction Checker
Add your medications below and check for clinically significant interactions. Sourced from FDA and NIH DailyMed databases.
Your Medications
Type a drug name to search, then add it to your list.
Get Medication Alerts
We will notify you about FDA warnings, recalls, and new interaction discoveries for your medications.
How This Tool Works
The Drug Interaction Checker lets you add multiple medications to a list, then checks every pair for clinically significant interactions. The database covers 100 or more of the most commonly prescribed drugs in the US and maps 90 or more specific interaction pairs sourced from FDA labeling and NIH DailyMed data. Each interaction result includes a severity rating (Severe, Moderate, or Mild), a plain-language description, the pharmacological mechanism, the data source, and a specific clinical recommendation. Severe interactions auto-expand so you see the most critical findings immediately. The tool also generates contextual suggestions: a link to compare pharmacy prices for your medications, a supplement safety check, and an option to save your drug list for future reference.
Example Scenario
A patient taking warfarin (blood thinner), metoprolol (beta blocker), omeprazole (acid reflux), and ibuprofen (pain) adds all four drugs and clicks "Check Interactions." The tool returns a Severe interaction between warfarin and ibuprofen (NSAIDs increase bleeding risk and can displace warfarin from protein binding), a Moderate interaction between warfarin and omeprazole (slight increase in warfarin levels in some patients), and confirms no known interaction between metoprolol and omeprazole. Each card shows the mechanism, recommendation (use acetaminophen instead of ibuprofen, monitor INR), and the FDA or DailyMed source. The patient now has specific, actionable information to discuss with their doctor or pharmacist before their next appointment.
Frequently Asked Questions
Where does the interaction data come from?
Interaction data is sourced from FDA-approved drug labeling (package inserts), NIH DailyMed, and established pharmacology references. Each interaction entry cites either "FDA" or "DailyMed NIH" as its primary source. The database focuses on the most clinically significant interactions rather than attempting to be exhaustive.
What does it mean if no interactions are found?
A "No Known Interactions Found" result means your specific drug combination does not appear in our database. This does not guarantee safety. Our database covers common interactions but is not exhaustive. Always verify with your pharmacist, who has access to comprehensive interaction databases and your complete medication history.
Does this check supplement interactions too?
This tool focuses on prescription drug-to-drug interactions. For supplement interactions, we recommend Health Britannica for human supplements or Petmaxxing for pet supplements. Drug-supplement interactions (like St. John's Wort with SSRIs) are an important concern that falls outside the current scope of this tool.
How many drugs can I check at once?
There is no hard limit. The tool checks every possible pair, so adding 5 drugs checks 10 pairs, and adding 8 drugs checks 28 pairs. For patients with complex medication regimens, this tool is particularly valuable because interaction risk increases exponentially with each additional medication.
Is my medication list stored anywhere?
No. All processing happens in your browser. Your medication list is not sent to any server or stored in any database. When you close the page, the data is gone. Use the "Save your drug list" feature to store it locally on your device.
Related Resources
- Patient Assistance Finder -- Find programs to reduce your medication costs
- Formulary Checker -- Check if your drug is covered by insurance
- RxGrab Pharmacy Finder -- Compare prices across 8 pharmacies
- Supplement Safety Guide -- Check supplement safety alongside medications