Drug interaction checker
Common clinically significant pairs: enter two drug or substance names
Full pair list
The database covers the best-known interactions (not exhaustive). Always read the leaflet and ask a doctor/pharmacist.
- MajorWarfarin + NSAIDs: major GI bleeding risk. Prefer paracetamol for pain.
- MajorFluoroquinolones/metronidazole potentiate warfarin — INR monitoring required.
- ModerateGrapefruit blocks CYP3A4 — statin levels rise, rhabdomyolysis risk. Avoid.
- MajorSSRIs + tramadol/triptans: serotonin syndrome risk (fever, tremor, confusion).
- MajorACE inhibitors/ARBs + potassium/spironolactone: dangerous hyperkalemia. Monitor K+.
- MajorMetformin + iodinated contrast: lactic acidosis risk — withhold 48 h around CT.
- ModerateAntacids/Ca/Mg/Fe reduce levothyroxine absorption — separate by ≥4 h.
- MajorAmiodarone/verapamil raise digoxin ~70% — toxicity. Reduce dose, monitor.
- MajorNSAIDs/diuretics reduce lithium clearance — narrow window, toxicity risk.
- ModerateOmeprazole blocks clopidogrel activation (CYP2C19) — pantoprazole preferred.
- MajorPDE-5 inhibitors + nitrates: severe hypotension — absolutely contraindicated.
- MajorOpioids + alcohol: respiratory depression — life-threatening.
- MajorBenzodiazepines + alcohol: additive CNS depression — overdose risk.
- MajorNSAIDs reduce methotrexate clearance — bone marrow toxicity.
- ModerateCa/Mg/Fe chelate fluoroquinolones — antibiotic not absorbed. Separate 2–4 h.
- MajorIsotretinoin + tetracyclines: intracranial hypertension risk.