Drug Interaction Safety Checker

Real-time drug-drug interaction detection with five-level severity classification (A/B/C/D/X), modeled after the Lexicomp grading system. This skill checks for drug-disease contraindications, drug-dose range violations, and drug-food interactions by referencing FDA adverse event databases and peer-reviewed clinical pharmacology sources.

Quick Install

npx skills add Open-Medica/open-medical-skills --skill drug-interaction-checker

What It Does

Severity classification: Grades every interaction on the A/B/C/D/X scale, where A indicates no known interaction and X indicates a contraindicated combination that should be avoided entirely
Multi-axis screening: Evaluates drug-drug, drug-disease, drug-food, and drug-dose interactions in a single pass rather than checking each axis independently
Duplicate therapy detection: Identifies overlapping pharmacologic classes when two or more agents share the same mechanism of action
Renal and hepatic adjustment alerts: Flags medications that require dose modifications based on organ function, including CrCl-based thresholds and Child-Pugh scoring
Structured output: Returns interaction results in a machine-readable format that downstream agents or clinical dashboards can consume directly

Clinical Use Cases

Polypharmacy review: A hospitalist adding a new antibiotic to a patient already on eight chronic medications can run the full regimen through the checker before placing the order
Transitions of care: During discharge reconciliation, the skill screens the combined inpatient and outpatient medication lists for conflicts introduced during the hospital stay
Warfarin management: Catches CYP2C9 and CYP3A4 interactions with newly prescribed drugs that may potentiate or diminish anticoagulant effect
Geriatric medication review: Flags Beers Criteria medications and high-risk combinations common in elderly patients taking five or more concurrent drugs

Safety & Evidence

Safety Classification: Safe — The skill provides information and alerts only; it does not modify orders, prescriptions, or patient records. All interaction data is derived from published references and regulatory databases.
Evidence Level: High — Interaction severity grading follows established frameworks (Lexicomp A-X scale) backed by FDA labeling, DailyMed, and published pharmacokinetic studies.

Example Usage

Checking a two-drug pair:

Check interaction between warfarin and fluconazole

Result: Severity X (Avoid Combination). Fluconazole is a potent CYP2C9 inhibitor that significantly increases warfarin plasma concentrations. Case reports document INR values exceeding 10 with concurrent use. If unavoidable, reduce warfarin dose by 25-50% and monitor INR every 2-3 days.

Screening a full medication list:

Screen the following regimen for interactions:
- Lisinopril 20mg daily
- Metformin 1000mg BID
- Atorvastatin 40mg daily
- Amlodipine 5mg daily
- Ibuprofen 600mg TID

Result: Severity C (Monitor Therapy) between lisinopril and ibuprofen: NSAIDs may reduce antihypertensive efficacy and increase risk of acute kidney injury, particularly in volume-depleted patients. Consider acetaminophen as an alternative analgesic.

Technical Details

Category: Treatment
Author: OMS Contributors
License: MIT
Version: 1.0.0
Specialty: Pharmacy, Clinical Pharmacology

References

Lexicomp Drug Interaction Classification System (Wolters Kluwer)
FDA Adverse Event Reporting System (FAERS) database
Hansten PD, Horn JR. Drug Interactions Analysis and Management. Wolters Kluwer, updated quarterly.
American Geriatrics Society 2023 Updated Beers Criteria for Potentially Inappropriate Medication Use in Older Adults. J Am Geriatr Soc. 2023;71(7):2052-2081.
DailyMed drug labeling repository (National Library of Medicine)

This skill is part of Open Medical Skills, a curated marketplace of medical AI skills maintained by physicians for physicians and the healthcare industry.