Drug Interaction Severity Calculator
Quantify the potential severity of a drug-drug interaction based on individual severity scores and patient risk factors.
Medical Disclaimer
This calculator is for informational and educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making decisions about your health. Never disregard professional medical advice or delay seeking it because of results from this tool.
Inputs
Results
Combined Interaction Score
6
Risk Level (1=Low, 4=Critical)
2
How to Use This Calculator
- Rate Drug 1 Severity Score (0–10) based on the drug's individual risk profile — look up the drug's known adverse effect burden.
- Rate Drug 2 Severity Score (0–10) similarly for the second medication.
- Enter the Combined Risk Multiplier (1–3): use 1 for no known interaction synergy, and higher values for documented pharmacodynamic or pharmacokinetic interactions.
- Set the Patient Age Risk Factor (1 = young adult, 2 = elderly, 3 = very elderly or pediatric) and Renal Risk Factor based on creatinine clearance.
- Review the Overall Interaction Severity score and whether the combination Requires Monitoring — use this to guide counseling, therapy changes, or monitoring plans.
How the result changes with Combined Risk Multiplier
| Combined Risk Multiplier | Combined Interaction Score | Risk Level (1=Low, 4=Critical) |
|---|---|---|
| 1.2 | 4.8 | 1 |
| 1.7 | 6.8 | 2 |
| 2.3 | 9.2 | 2 |
| 2.8 | 11.2 | 2 |
What each input means
- Drug 1 Severity Score
- Severity rating of the first drug (0 = very safe, 10 = high risk).
- Drug 2 Severity Score
- Severity rating of the second drug (0 = very safe, 10 = high risk).
- Combined Risk Multiplier
- Multiplier for known interaction severity (1 = no synergy, 3 = severe synergy).
- Patient Age Risk Factor
- Age-related risk multiplier (1 = young adult, 2 = elderly, 3 = very elderly or pediatric).
- Renal Risk Factor
- Renal function risk multiplier (1 = normal, 2 = impaired, 3 = severe impairment).
How this is calculated
Worked example, using the default values
- Identify Input Parameters4 parametersDrug 1 Severity Score = 3, Drug 2 Severity Score = 5, Combined Risk Multiplier = 1.5, Patient Age Risk Factor = 1 = 5 input(s) provided
- Calculate Combined Interaction ScoreCombined Interaction Score6 = 6
- Calculate Risk LevelRisk Level2 = 2
- Calculate Requires MonitoringRequires Monitoring1 = 1
- Calculate Base Severity ScoreBase Severity Score4 = 4
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