Run Detail

{ "rows": [ { "id": "a41f", "significant": true, "mechanism": "fluconazole inhibits CYP2C9 (and CYP3A4), reducing warfarin metabolism", "effect": "Elevated INR with bleeding risk, even with intermittent 150 mg dosing", "action": "Check INR within 3-5 days of starting fluconazole and after any re-dose; reduce warfarin dose if INR rises", "numbers": ["INR check within 3-5 days"], "note": "The 150 mg weekly dose is not low enough to ignore this; single-dose fluconazole for vaginitis can still push a sensitive INR." }, { "id": "7c02", "significant": true, "mechanism": "clarithromycin strongly inhibits CYP3A4, blocking simvastatin metabolism", "effect": "Markedly raised simvastatin exposure with myopathy and rhabdomyolysis risk", "action": "Suspend simvastatin for the duration of clarithromycin therapy, or use a statin not dependent on CYP3A4 such as rosuvastatin or pravastatin", "numbers": [], "note": "Short clarithromycin courses can be covered by holding the statin; this is the pragmatic choice for most patients." }, { "id": "b9d5", "significant": true, "mechanism": "linezolid is a weak nonselective MAO inhibitor; additive with sertraline's serotonergic effect", "effect": "Serotonin syndrome — agitation, hyperreflexia, hyperthermia", "action": "Avoid the combination; if linezolid is essential, hold sertraline and monitor for serotonergic signs during linezolid therapy and for 2 weeks after in susceptible patients", "numbers": ["2 weeks monitoring after linezolid"], "note": "Citalopram or escitalopram are somewhat lower-risk SSRIs but not risk-free; alternatives to linezolid (e.g., dalbavancin) are often the cleaner solution." }, { "id": "3e18", "significant": true, "mechanism": "additive nitric oxide/cGMP-mediated vasodilation", "effect": "Profound hypotension, syncope, possible cardiac ischemia", "action": "Contraindicated — do not co-prescribe; sildenafil must be washed out 24 hours before any nitrate is given for chest pain", "numbers": ["24 hours sildenafil washout before nitrate"], "note": "Patients on daily nitrates effectively cannot use PDE5 inhibitors at all; this needs explicit counseling, not just a pharmacy flag." }, { "id": "c6a7", "significant": true, "mechanism": "additive effects on potassium handling — ACE inhibition lowers aldosterone and spironolactone blocks the mineralocorticoid receptor", "effect": "Hyperkalemia, with risk of arrhythmia", "action": "Check serum potassium and renal function within 1-2 weeks of starting or changing either dose, then periodically", "numbers": ["potassium check within 1-2 weeks"], "note": "Risk rises sharply with reduced eGFR, diabetes, or older age despite the normal-baseline assumption; monitor tighter in those groups." }, { "id": "2f4b", "significant": true, "mechanism": "TMP-SMX is an antifolate that also competes with methotrexate for renal tubular secretion and displaces it from protein binding", "effect": "Severe pancytopenia and mucositis from amplified antifolate toxicity", "action": "Avoid TMP-SMX; choose an alternative antibiotic (e.g., nitrofurantoin or a cephalosporin per indication)", "numbers": [], "note": "Even low-dose weekly MTX interacts; the combination has caused fatal myelosuppression. Pneumocystis prophylaxis alternatives should be discussed before starting MTX, not after." }, { "id": "8d31", "significant": true, "mechanism": "omeprazole inhibits CYP2C19, reducing clopidogrel activation to its active metabolite", "effect": "Reduced antiplatelet effect; possible increase in thrombotic events", "action": "Switch the proton pump inhibitor to pantoprazole", "numbers": [], "note": "Pharmacokinetic interaction is real; clinical outcome data (e.g., COGENT) suggest modest risk, but since a zero-cost equivalent alternative exists, switching is standard practice." }, { "id": "5a9e", "significant": false, "mechanism": "none", "effect": "none", "action": "No action needed", "numbers": [], "note": "Pantoprazole is the weakest CYP2C19 inhibitor of the PPIs and is the standard pairing with clopidogrel." }, { "id": "f072", "significant": true, "mechanism": "rifampin is a potent inducer of CYP3A4 and of hepatic/intestinal estrogen metabolism", "effect": "Contraceptive failure — unintended pregnancy and breakthrough bleeding", "action": "Use a non-hormonal or non-interacting method (copper IUD, progestin implant or injection with caution) for the full course and for 4 weeks after stopping rifampin", "numbers": ["4 weeks backup contraception after rifampin stops"], "note": "Combined pills are effectively unreliable for the entire tuberculosis treatment course, which is usually months." }, { "id": "1b6c", "significant": false, "mechanism": "none", "effect": "none", "action": "No action needed", "numbers": [], "note": "The antibiotic-OC failure myth applies to enzyme inducers like rifampin, not amoxicillin; GI upset is the only theoretical concern and does not warrant backup contraception." }, { "id": "e3f9", "significant": true, "mechanism": "amiodarone inhibits P-glycoprotein, reducing renal and biliary clearance of digoxin", "effect": "Digoxin toxicity — nausea, visual disturbance, arrhythmias", "action": "Reduce the digoxin dose by approximately 50% when starting amiodarone and monitor digoxin levels and for toxicity", "numbers": ["reduce digoxin dose by 50%"], "note": "Interaction develops over days to weeks as amiodarone accumulates; check levels about 1-2 weeks after initiation, not just at day 1." }, { "id": "94a2", "significant": true, "mechanism": "NSAID reduces renal prostaglandins, decreasing lithium clearance", "effect": "Rising lithium levels with tremor, confusion, and lithium toxicity", "action": "Avoid ibuprofen — use acetaminophen; if an NSAID is unavoidable, reduce lithium dose (often by 25-40%) and recheck a lithium level within about 5-7 days", "numbers": ["reduce lithium dose by 25-40%", "lithium level within 5-7 days"], "note": "Celecoxib also raises lithium; acetaminophen is the safe analgesic choice for lithium patients." }, { "id": "6d70", "significant": true, "mechanism": "allopurinol inhibits xanthine oxidase, blocking conversion of azathioprine to 6-MU and shunting it to 6-thioguanine nucleotides", "effect": "Profound myelosuppression — neutropenia, pancytopenia", "action": "Reduce azathioprine dose to 25-33% of the usual dose when co-prescribed, and monitor CBC", "numbers": ["reduce azathioprine to 25-33% of usual dose"], "note": "The dose cut is mandatory, not optional — full-dose combination has caused fatal marrow failure." }, { "id": "0c85", "significant": true, "mechanism": "ciprofloxacin inhibits CYP1A2, blocking tizanidine clearance", "effect": "Markedly elevated tizanidine levels causing severe hypotension and sedation", "action": "Contraindicated — do not co-prescribe; use an alternative antibiotic that does not inhibit CYP1A2 (e.g., a cephalosporin) or discontinue tizanidine for the antibiotic course", "numbers": [], "note": "Fluvoxamine is the other classic 1A2-inhibitor to watch for; levofloxacin is a weaker 1A2 inhibitor but still not a preferred partner." }, { "id": "a7be", "significant": true, "mechanism": "carbamazepine is a strong inducer of CYP3A4 and P-glycoprotein, increasing apixaban clearance", "effect": "Subtherapeutic apixaban levels with stroke risk in atrial fibrillation", "action": "Avoid the combination — use an anticoagulant unaffected by strong induction (warfarin with INR monitoring) or an alternative anticonvulsant (levetiracetam)", "numbers": [], "note": "Effect persists for 1-2 weeks after stopping carbamazepine, so apixaban cannot simply be restarted immediately." }, { "id": "d218", "significant": true, "mechanism": "clarithromycin inhibits CYP3A4 and P-glycoprotein, blocking colchicine clearance", "effect": "Colchicine toxicity — GI symptoms, neuromyotoxicity, marrow suppression", "action": "Avoid clarithromycin; use an alternative antibiotic (azithromycin), and for treatment courses that must overlap, limit colchicine to a single 0.6 mg dose then 0.3 mg", "numbers": ["colchicine single 0.6 mg dose then 0.3 mg if unavoidable"], "note": "Contraindicated outright in renal or hepatic impairment; azithromycin gives gram-positive coverage without 3A4 inhibition." }, { "id": "4f63", "significant": true, "mechanism": "ibuprofen competes for the aspirin acetylation site on COX-1 in platelets, blocking aspirin's irreversible antiplatelet effect", "effect": "Loss of cardioprotection with increased myocardial infarction risk in secondary prevention", "action": "Take the 81 mg aspirin at least 2 hours before ibuprofen (or 8 hours after), or substitute acetaminophen/naproxen if analgesia is needed regularly", "numbers": ["aspirin at least 2 hours before ibuprofen", "8 hours after ibuprofen"], "note": "A single properly timed daily dose of ibuprofen is probably acceptable, but chronic multi-dose ibuprofen plus aspirin defeats the aspirin entirely." }, { "id": "b5cd", "significant": true, "mechanism": "additive RAAS blockade (ACE inhibition plus neprilysin inhibition/ARB) plus concurrent ACE inhibitor with neprilysin inhibition raises bradykinin", "effect": "Angioedema and severe hypotension", "action": "Contraindicated — do not use together; require a 36-hour washout when switching from lisinopril to sacubitril/valsartan", "numbers": ["36 hours washout between ACE inhibitor and sacubitril/valsartan"], "note": "The 36-hour rule exists specifically because of angioedema risk from overlapping bradykinin effects." }, { "id": "27ea", "significant": false, "mechanism": "none", "effect": "none", "action": "No action needed with normal renal function", "numbers": [], "note": "Contrast-induced AKI triggering metformin accumulation only matters when renal function is impaired — hold metformin for 48 hours with reassessment of renal function if eGFR is below 30, or below 60 with intra-arterial contrast or other AKI risks." }, { "id": "ec46", "significant": true, "mechanism": "MAO inhibition prevents metabolism of the indirect sympathomimetic pseudoephedrine", "effect": "Hypertensive crisis with risk of intracranial hemorrhage and arrhythmia", "action": "Contraindicated — avoid pseudoephedrine entirely in MAOI-treated patients; wait 14 days after stopping phenelzine before using sympathomimetics", "numbers": ["14 days washout after phenelzine"], "note": "Warn against OTC decongestants specifically; patients do not perceive them as drugs. Phenylephrine carries the same risk." } ] }