Why can grapefruit affect some statins?
Grapefruit can interfere with how the body handles certain medicines. The effect depends on the specific drug.
📋Drug-label information via openFDA·
🔗Searchable interaction records·
💊Check 20 drugs at once·
⚡Instant drug name autocomplete·
📸Camera label scan·
⚠️Severity-ranked results·
🏥FDA labels + NIH drug identities·
📤Send to My Doc / Caretaker·
📋Drug-label information via openFDA·
🔗Searchable interaction records·
💊Check 20 drugs at once·
⚡Instant drug name autocomplete·
📸Camera label scan·
⚠️Severity-ranked results·
🏥FDA labels + NIH drug identities·
📤Send to My Doc / Caretaker·
Check Drug Interactions (CDI)
Built for everyday people
Enter up to 20 medications to check for interactions.
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For informational purposes only. Not a substitute for professional medical advice. Always consult your doctor or pharmacist.
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Just looking up one drug?
How It Works
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Type or scan your medications
Choose the matching medication from autocomplete, using NIH/NLM RxNorm identifiers. You can also scan a pill bottle label and confirm the result.
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Add up to 20 drugs at once
CDI checks each pair against its stored interaction records. A missing record does not establish that a combination is safe.
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See severity-ranked results
Review CDI summaries and their recorded source attribution. Classifications help organize the records; your pharmacist can assess your specific medicines and circumstances.
Why CDI is Different
openFDA
Label Data
Selected drug-label information, processed into searchable records.
RxNorm
Drug Identities
NIH/NLM identifiers help match medication names.
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Drugs Checked at Once
Each pair is checked against CDI records. Coverage is not comprehensive.
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Severity Classifications
Contraindicated, major, moderate, minor, and unknown. Unknown does not mean safe.
Why CDI exists
Making publicly funded drug information genuinely accessible to the public.
FDA labeling and NIH/NLM resources contain valuable drug information. CDI organizes source material into a tool patients and caregivers can search, understand, and verify. Educational explanations help make technical wording accessible; the original evidence remains the reference.
What Are Drug Interactions?
A drug interaction occurs when one medication alters the way another works in your body — raising or lowering blood levels, amplifying side effects, or blocking the intended effect altogether. Interactions can occur between two prescription medications, between a prescription and an over-the-counter drug, or between a drug and a food, supplement, or herbal product.
CDI displays the classification stored with each record: contraindicated, major, moderate, minor, or unknown. These classifications are processed summaries, not personalized treatment advice. They may contain errors and do not account for every formulation, dose, or patient factor.
Use the results to prepare questions for your pharmacist or prescriber. Do not start, stop, or change a prescribed medication based solely on this tool.
Explore Source-Linked Explanations
These educational articles link to a specific source and section, explain its wording, and describe the limits of the explanation.
Why does warfarin labeling warn about aspirin?
Warfarin labeling lists aspirin among medicines that increase bleeding risk when taken with warfarin.
How Our Drug Interaction Checker Works
Enter any drug name — brand or generic — into the search fields above. Our autocomplete draws from the NIH RxNorm database to identify the canonical drug name and its RxCUI identifier. Once you have confirmed at least two drugs, click Check Interactions to see every pair evaluated simultaneously.
Matching records are ranked by their stored severity. Each result shows a processed description and, where available, a mechanism summary and source attribution. Automated extraction can make mistakes; the records are not verbatim quotations or an independent clinical review.
The checker supports up to 20 drugs at once. It does not evaluate every aspect of a medication regimen or establish that combinations are safe. On mobile, you can photograph a pill bottle label and our OCR feature will extract and search the drug name automatically.
Frequently Asked Questions
What is a drug interaction?
A drug interaction occurs when one medication changes the way another medication works in your body. Interactions can increase a drug's side effects, reduce its effectiveness, or — in serious cases — cause life-threatening reactions. They can happen between two prescription drugs, between a prescription and an over-the-counter drug, or between a drug and a food or supplement.
How serious are drug interactions?
CDI displays contraindicated, major, moderate, minor, and unknown classifications. These summarize source wording and are not an individual risk assessment. Unknown means the severity has not been established in the record; it does not mean safe.
Where does your interaction data come from?
CDI primarily uses FDA drug labeling via openFDA, with NIH/NLM RxNorm for drug identities. Limited curated-reference records are explicitly tagged. Source text, extracted summaries, and educational explanations are distinct; see our methodology for details.
Can I check more than two drugs at once?
Yes. Our checker supports up to 20 drugs simultaneously. We look up each pair and display matching CDI records ranked by their stored severity. Coverage is incomplete: a missing record does not establish that a combination is safe.
Does "no interaction found" mean it's safe to take both?
No. It means no matching record was found in the CDI dataset. Our extraction and coverage are incomplete, and a missing record is not proof that FDA labeling contains no warning. Confirm your specific medicines, formulations, and health circumstances with your pharmacist or physician.
Is this tool a substitute for talking to my pharmacist?
No. checkdruginteractions.com is an informational reference tool. Your pharmacist has access to your full medication history and can apply clinical judgment to your specific situation. This tool helps you arrive at that conversation informed — not replace it.