Drug Interaction Checker

February 2026 · 4 min

Overview

The Drug Interaction Checker provides real-time drug-drug interaction alerts within the OPD prescription workflow. When a doctor adds two or more medications to a prescription, the system automatically cross-references them against a built-in interaction database covering 200+ common drug pairs, flagging potential interactions by severity before the prescription is finalized.

How It Works

The interaction engine lives in lib/drug-interactions.ts and is invoked automatically in the OPD consultation prescription tab:

1. Prescription Entry -- Doctor adds medications to the prescription list
2. Real-time Check -- When 2+ medications are present, the DrugInteractionAlert component runs checkInteractions() against the full medication list
3. Alert Display -- Interactions are displayed inline as color-coded cards directly below the prescription table
4. Clinical Decision -- The doctor can review the interaction, read the clinical recommendation, and decide to continue, adjust, or remove the medication

No extra click is required -- the alerts appear automatically as medications are added.

Severity Levels

Interactions are classified into three severity tiers:

• Major (Red) -- Potentially life-threatening or requiring immediate intervention. Examples: Warfarin + NSAIDs, MAOIs + SSRIs, Methotrexate + NSAIDs. These display with a red border and prominent warning icon.
• Moderate (Amber) -- May require dosage adjustment or monitoring. Examples: ACE inhibitors + Potassium supplements, Statins + Macrolides. These display with an amber/yellow border.
• Minor (Blue) -- Generally low risk but worth noting. Examples: Antacids + certain antibiotics (timing separation needed). These display with a blue informational border.

Each alert includes: the two drugs involved, severity level, interaction mechanism description, and a clinical recommendation.

Interaction Database

The interaction database covers:

• 200+ drug-drug pairs with evidence-based severity classification
• Generic name matching -- matches on generic names (e.g., 'aspirin', 'metformin') using case-insensitive partial matching
• Mechanism descriptions -- explains WHY the interaction occurs (e.g., 'CYP3A4 inhibition', 'additive bleeding risk')
• Clinical recommendations -- actionable guidance (e.g., 'Monitor INR closely', 'Separate doses by 2 hours')

The database is extensible -- hospital pharmacists can add custom interaction rules via the Pharmacy > Drug Interactions page.

Integration Points

The Drug Interaction Checker integrates with:

• OPD Consultation -- Inline alerts in the prescription tab when composing prescriptions
• Pharmacy Dispensing -- Pharmacist sees interaction warnings when verifying prescriptions
• Pharmacy Interactions Page -- Dedicated lookup tool at /dashboard/pharmacy/interactions for checking arbitrary drug combinations
• Patient Allergy Data -- Cross-references against the patient's recorded allergies (separate from drug-drug interactions)
• eMAR -- Nursing staff see interaction flags when administering medications to inpatients

Notes

Related topics