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Drug–Drug Interaction Checker

Most Popular Free

Enter up to 20 medications to instantly check all pairwise drug interactions. Every result is severity-rated with clinical explanations, mechanisms and management recommendations.

Add MedicationsType a name, press Enter or click Add.
Check InteractionsClick the generate button below.
Review ResultsFilter by severity level.
Export & SharePDF, CSV or Print.
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Supports brand and generic names. Search from 500+ medications. Maximum 20 drugs per check.

Quick Add:

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Interaction Report
Export:
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How to Use the Drug Interaction Checker

The RxTools Pro Drug Interaction Checker is designed to deliver the most comprehensive free drug interaction analysis available online. Here is a complete guide to using it effectively and interpreting your results.

Adding Medications

Type any medication name - brand or generic - in the input field. Our autocomplete database covers 500+ commonly prescribed and dispensed drugs. As you type, matching suggestions appear in a dropdown. Press Enter or select from the dropdown to add the drug as a tag. Use the Quick Add chips for the most frequently checked medications. Click the × on any drug tag to remove it before running the check. You can add up to 20 medications per check.

Reading Your Results

After clicking Check Interactions, every possible pairwise combination in your medication list is analysed simultaneously. Results are displayed as individual interaction cards, sorted from most to least severe. Each card shows the drug pair, the severity classification, the clinical effect (what happens to the patient), the pharmacological mechanism (why it happens), and the management recommendation (what to do about it). Use the severity filter buttons to focus on specific risk levels.

Severity Classifications

Contraindicated - this combination must never be used. Major - high risk requiring immediate clinical attention, dose adjustment or an alternative. Moderate - requires monitoring and prescriber awareness. Minor - low risk but may cause additive effects or modest efficacy reduction.

Exporting Results

After your check, the export bar below the results allows you to download a PDF report formatted for sharing with your doctor or pharmacist, export raw interaction data as a CSV file with UTF-8 BOM for full Excel compatibility, or print directly using your browser. All export features are completely free with no account required.

Clinical Limitations

This tool checks for known, documented drug–drug interactions based on established clinical databases. It does not account for individual patient factors including CYP450 genetic polymorphisms, specific doses and formulations, duration of concurrent therapy, severity of hepatic or renal impairment, or the full clinical context of the patient's condition. Always consult a licensed pharmacist or physician before making any change to a medication regimen.

Frequently Asked Questions

Up to 20 medications per check, covering all possible pairwise combinations. For a patient on 10 drugs, that is up to 45 interaction pairs checked simultaneously in a single click.
Yes. Common brand names are automatically mapped to their generic equivalents. Tylenol is recognised as paracetamol/acetaminophen, Advil as ibuprofen, Coumadin as warfarin, Prozac as fluoxetine, Viagra as sildenafil, and many more. The autocomplete suggestions show all mapped names.
Yes - completely free with no registration, no login and no usage limits. PDF export, CSV download and print are all included at no cost, with no hidden features behind a paywall.
Contraindicated means the two drugs must never be taken together under any circumstances. Examples include MAOIs combined with SSRIs (potentially fatal serotonin syndrome), opioids combined with benzodiazepines (respiratory depression and overdose death), and sildenafil combined with nitrates (severe, potentially fatal hypotension).
No. This tool is for informational and educational purposes only. It screens for known interactions but cannot account for individual patient factors - genetics, organ function, specific dosages, duration of therapy and clinical context. Always share results with your pharmacist or physician before making any medication change. Never stop or adjust a prescribed medication based solely on the output of an online tool.