Drug-Drug Interaction Checker API

Drug Interaction Database for Software

Improve medication outcomes, assist in clinical decision-making, and reduce medical errors and patient risk. You can easily provide drug-drug interaction alerts by integrating our database API with your software.

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Product Value


Each DDI alert includes detailed descriptions to help your users understand the interaction management options.

Always Up
To Date

The product and ingredient lists are updated on a daily basis to make sure that interactions for new drug products are available through the API right away.

Friendly API

The DDI checker works with common drug identifiers so it is easy to integrate our API into your existing systems.

Instantly search our database of more than 1.3 million drug-drug interactions.

It is easy to get drug-drug interactions for a medication list. With a single API call, you can search for any between the drugs in the list. You can search by ingredient identifiers, product identifiers such as NDC codes, RxNorm codes, or product concept identifiers or use one of our built-in drug searches to find drug products quickly. It is also possible to list all the interactions associated with a single drug.

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Each interaction includes a number of useful descriptions including a severity rating, a detailed description describing the mechanism of the drug-drug interaction and a description describing how to manage the interaction. Below is an example showing the interaction between Acetaminophen and Warfarin.

Drug-Drug Interaction Checker
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The metabolism of (R)-warfarin can be increased when combined with Acetaminophen.
Extended Description:
Warfarin is primarily metabolized by CYP2C9 and to a lesser extent by CYP2C19 and CYP3A4. Agents known to be strong CYP3A4 inducers will increase the metabolism of warfarin. Hence, concomitant use of these agents will reduce warfarin plasma concentrations and should be avoided if possible [FDA label].
Evidence Level:
Level 1
Avoid concurrent use of warfarin and CYP3A4 inducers whenever possible. If the combination must be used, conduct additional INR monitoring and adjust the dosage as necessary when starting, stopping, or changing the dosage of a CYP3A4 inducer.
API Query
  "interactions": [
      "ingredient": {
        "drugbank_id": "DB00316",
        "name": "Acetaminophen"
      "affected_ingredient": {
        "drugbank_id": "DB00682",
        "name": "Warfarin"
      "description": "The risk or severity of adverse effects can be increased when Acetaminophen is combined with Warfarin.",
      "extended_description": "Chronic oral acetaminophen use at a dose of 4,000 mg/day has been demonstrated to cause an increase in the international normalized ratio (INR) for some patients who have been stabilized on sodium warfarin as an anticoagulant. This interaction is thought to occur through augmented effects on vitamin K antagonism, increasing the risk of bleeding.",
      "action": "increase_adverse_effects",
      "severity": "moderate",
      "subject_dosage": null,
      "affected_dosage": null,
      "evidence_level": "level_1",
      "management": "Use this combination with caution. Avoid warfarin doses of 4, 000 mg/day or higher when acetaminophen is used, and regularly monitor INR. Adjust drug dosage as necessary, according to clinical response."
  "total_results": 1

Drug Input

Choose up to 40 different drugs and check for all interactions between them in a single request.


A brief description of the drug-drug interaction.

Extended Description

A detailed description of why the interaction occurs and the effect of the interaction.


The severity of each drug interaction is rated as minor, moderate or major.

Evidence Level

A rating for the strength of the evidence supporting each drug interaction.


The recommended procedure to deal with this type of drug-drug interaction.

Report data comes from clinical guidelines, labels, and scientific literature covering approved drugs by the Food and Drug Administration (FDA), Health Canada and the European Medical Association (EMA) and each drug-drug interaction entry includes a listing of relevant references for the interaction.

The data is curated and updated daily by our team of pharmacists, pharmacologists and medical doctors.

Learn more about our Clinical API

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Contact our sales team to add DrugBank’s Drug-Drug Interaction data to your software.