The Drug Interaction Checker provides a clinical reference tool to evaluate potential pharmacological conflicts between pairs of prescription drugs, over-the-counter medications, and supplements.

### Clinical Interaction Categories When two medications share metabolic pathways or exert synergistic physiological effects, co-administration can cause adverse reactions: - **Contraindicated (Red)**: Severe risk where co-administration should be strictly avoided due to life-threatening complications. - **Major Risk (Orange)**: Substantial clinical risk requiring alternative therapy or intensive physician monitoring. - **Moderate Risk (Yellow)**: Moderate interaction where dosage adjustments or spaced administration times may be necessary. - **Minor (Blue)**: Low-level pharmacokinetic interaction unlikely to cause clinically significant harm.

### Worked Example: Warfarin & Aspirin Selecting **Warfarin** (an oral anticoagulant) and **Aspirin** (an antiplatelet NSAID): - **Severity Rating**: **Major Interaction** - **Clinical Mechanism**: Both medications inhibit blood clotting through distinct mechanisms—warfarin reduces hepatic synthesis of vitamin K clotting factors, while aspirin irreversibly inhibits platelet cyclooxygenase-1 (COX-1). - **Adverse Risk**: Concurrent use significantly elevates the risk of gastrointestinal hemorrhage and intracranial bleeding.

### Medical Advisory & Local Processing This tool operates as an educational reference based on published pharmacokinetic datasets. It is not medical advice. Never discontinue or adjust prescription dosages without consulting your licensed physician or pharmacist. All lookups execute locally within your browser without sending patient records across the network.