Drug Interactions Guide

Evidence-based guide to common drug interactions. Check 140+ medication combinations with severity ratings, mechanisms, and recommendations.

Articles

• A

  abiraterone and prednisolone: Interaction, Risks, and Safer

  Interaction between Abiraterone and Prednisolone: minor severity. Abiraterone inhibits CYP17, causing mineralocorticoid excess; prednisolone is co

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• A

  ace-inhibitor and potassium: Interaction, Risks, and Safer

  Interaction between Ace Inhibitor and Potassium: moderate severity. ACE inhibitors raise serum potassium; supplements compound this.

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• A

  ace-inhibitor and spironolactone: Interaction, Risks, and Safer

  Interaction between Ace Inhibitor and Spironolactone: moderate severity. ACE inhibitors reduce aldosterone-mediated potassium excretion; combined with th

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• A

  allopurinol and azathioprine: Interaction, Risks, and Safer

  Interaction between Allopurinol and Azathioprine: major severity. Allopurinol inhibits xanthine oxidase, the enzyme responsible for inactivating 6

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• A

  alpha-blocker and sildenafil: Interaction, Risks, and Safer

  Interaction between Alpha Blocker and Sildenafil: moderate severity. Both phosphodiesterase-5 inhibitors and alpha-1 adrenergic blockers (doxazosin,

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• A

  amiodarone and flecainide: Interaction, Risks, and Safer

  Interaction between Amiodarone and Flecainide: major severity. Amiodarone inhibits CYP2D6 and CYP3A4, raising flecainide concentrations; both d

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• A

  amiodarone and simvastatin: Interaction, Risks, and Safer

  Interaction between Amiodarone and Simvastatin: major severity. Amiodarone inhibits CYP3A4 metabolism of simvastatin, increasing systemic exposu

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• A

  amiodarone and warfarin: Interaction, Risks, and Safer

  Interaction between Amiodarone and Warfarin: major severity. Amiodarone raises warfarin INR by 30-50% within 1-2 weeks. Reviewed by iMedic's medical...

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• A

  amitriptyline and fluoxetine: Interaction, Risks, and Safer

  Interaction between Amitriptyline and Fluoxetine: major severity. Fluoxetine inhibits CYP2D6 metabolism of amitriptyline, raising tricyclic levels

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• A

  amlodipine and clarithromycin: Interaction, Risks, and Safer

  Interaction between Amlodipine and Clarithromycin: moderate severity. Clarithromycin inhibits CYP3A4 metabolism of amlodipine, increasing plasma level

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• A

  amlodipine and simvastatin: Interaction, Risks, and Safer

  Interaction between Amlodipine and Simvastatin: moderate severity. Amlodipine inhibits CYP3A4, increasing simvastatin levels and risk of myopathy/r

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• A

  apixaban and ketoconazole: Interaction, Risks, and Safer

  Interaction between Apixaban and Ketoconazole: major severity. Ketoconazole is a strong dual inhibitor of CYP3A4 and P-glycoprotein, doubling a

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• A

  apixaban and rifampicin: Interaction, Risks, and Safer

  Interaction between Apixaban and Rifampicin: major severity. Rifampicin strongly induces CYP3A4 and P-glycoprotein, reducing apixaban exposur

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• A

  atazanavir and omeprazole: Interaction, Risks, and Safer

  Interaction between Atazanavir and Omeprazole: major severity. Proton pump inhibitors raise gastric pH, substantially reducing the dissolution

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• A

  atorvastatin and clarithromycin: Interaction, Risks, and Safer

  Interaction between Atorvastatin and Clarithromycin: major severity. Clarithromycin inhibits CYP3A4-mediated atorvastatin metabolism, increasing plas

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• A

  atorvastatin and diltiazem: Interaction, Risks, and Safer

  Interaction between Atorvastatin and Diltiazem: moderate severity. Diltiazem inhibits CYP3A4, increasing atorvastatin exposure approximately 50% wi

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• A

  azithromycin and citalopram: Interaction, Risks, and Safer

  Interaction between Azithromycin and Citalopram: moderate severity. Both agents prolong the QT interval through delayed cardiac repolarization, prod

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• A

  azole-antifungal and tacrolimus: Interaction, Risks, and Safer

  Interaction between Azole Antifungal and Tacrolimus: major severity. Azole antifungals (fluconazole, voriconazole, itraconazole) potently inhibit CYP

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• C

  calcium-channel-blocker and beta-blocker: Interaction, Risks, and

  Interaction between Calcium Channel Blocker and Beta Blocker: moderate severity. Combined non-dihydropyridine CCBs (verapamil, diltiazem) plus beta-blocker r

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• C

  carbamazepine and clarithromycin: Interaction, Risks, and Safer

  Interaction between Carbamazepine and Clarithromycin: major severity. Clarithromycin is a potent CYP3A4 inhibitor that reduces carbamazepine clearance

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• C

  carbamazepine and doxycycline: Interaction, Risks, and Safer

  Interaction between Carbamazepine and Doxycycline: moderate severity. Carbamazepine induces hepatic CYP3A4, accelerating doxycycline metabolism and re

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• C

  carbamazepine and ethinylestradiol: Interaction, Risks, and Safer

  Interaction between Carbamazepine and Ethinylestradiol: major severity. Carbamazepine is a strong inducer of CYP3A4 and UGT enzymes, accelerating metabo

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• C

  carbamazepine and valproate: Interaction, Risks, and Safer

  Interaction between Carbamazepine and Valproate: moderate severity. Carbamazepine induces CYP2C9 and UGT enzymes that metabolize valproate, reducing

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• C

  carbamazepine and warfarin: Interaction, Risks, and Safer

  Interaction between Carbamazepine and Warfarin: major severity. Carbamazepine is a potent inducer of CYP2C9 and CYP3A4, accelerating warfarin me

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• C

  carvedilol and fluoxetine: Interaction, Risks, and Safer

  Interaction between Carvedilol and Fluoxetine: moderate severity. Fluoxetine inhibits CYP2D6, the main enzyme for carvedilol metabolism, raising p

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• C

  ciclosporin and diltiazem: Interaction, Risks, and Safer

  Interaction between Ciclosporin and Diltiazem: moderate severity. Diltiazem inhibits CYP3A4 and P-glycoprotein, reducing ciclosporin metabolism an

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• C

  ciprofloxacin and sevelamer: Interaction, Risks, and Safer

  Interaction between Ciprofloxacin and Sevelamer: moderate severity. Sevelamer binds fluoroquinolones in the gastrointestinal tract, reducing oral bi

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• C

  ciprofloxacin and theophylline: Interaction, Risks, and Safer

  Interaction between Ciprofloxacin and Theophylline: major severity. Ciprofloxacin inhibits CYP1A2-mediated metabolism of theophylline, raising serum

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• C

  ciprofloxacin and tizanidine: Interaction, Risks, and Safer

  Interaction between Ciprofloxacin and Tizanidine: major severity. Ciprofloxacin is a potent CYP1A2 inhibitor, blocking metabolism of tizanidine an

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• C

  clarithromycin and colchicine: Interaction, Risks, and Safer

  Interaction between Clarithromycin and Colchicine: major severity. Clarithromycin inhibits CYP3A4 and P-glycoprotein, both responsible for colchici

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• C

  clarithromycin and simvastatin: Interaction, Risks, and Safer

  Interaction between Clarithromycin and Simvastatin: major severity. Clarithromycin is a strong CYP3A4 inhibitor that increases simvastatin plasma co

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• C

  clarithromycin and tacrolimus: Interaction, Risks, and Safer

  Interaction between Clarithromycin and Tacrolimus: major severity. Clarithromycin strongly inhibits intestinal and hepatic CYP3A4 metabolism of tac

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• C

  clopidogrel and esomeprazole: Interaction, Risks, and Safer

  Interaction between Clopidogrel and Esomeprazole: moderate severity. Esomeprazole inhibits CYP2C19, reducing conversion of clopidogrel to its active

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• C

  clopidogrel and fluoxetine: Interaction, Risks, and Safer

  Interaction between Clopidogrel and Fluoxetine: moderate severity. Fluoxetine inhibits CYP2C19, reducing conversion of clopidogrel to its active me

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• C

  clopidogrel and omeprazole: Interaction, Risks, and Safer

  Interaction between Clopidogrel and Omeprazole: moderate severity. Omeprazole inhibits CYP2C19, reducing conversion of clopidogrel to its active me

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• C

  clopidogrel and ssri: Interaction, Risks, and Safer Alternatives

  Interaction between Clopidogrel and Ssri: moderate severity. Both increase bleeding risk; SSRI also inhibits CYP2C19 reducing clopidogrel act

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• C

  clozapine and fluvoxamine: Interaction, Risks, and Safer

  Interaction between Clozapine and Fluvoxamine: major severity. Fluvoxamine potently inhibits CYP1A2, the primary enzyme metabolizing clozapine,

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• C

  cyclosporine and diltiazem: Interaction, Risks, and Safer

  Interaction between Cyclosporine and Diltiazem: moderate severity. Diltiazem inhibits CYP3A4 and P-glycoprotein, increasing cyclosporine exposure a

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• C

  cyclosporine and rosuvastatin: Interaction, Risks, and Safer

  Interaction between Cyclosporine and Rosuvastatin: major severity. Cyclosporine inhibits OATP1B1 and BCRP transporters, increasing rosuvastatin AUC

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• D

  dabigatran and dronedarone: Interaction, Risks, and Safer

  Interaction between Dabigatran and Dronedarone: major severity. Dronedarone inhibits P-glycoprotein, increasing dabigatran plasma concentrations

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• D

  dabigatran and verapamil: Interaction, Risks, and Safer

  Interaction between Dabigatran and Verapamil: moderate severity. Verapamil inhibits intestinal P-glycoprotein, increasing dabigatran absorption a

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• D

  dexamethasone and rivaroxaban: Interaction, Risks, and Safer

  Interaction between Dexamethasone and Rivaroxaban: moderate severity. Dexamethasone is a moderate CYP3A4 and P-glycoprotein inducer that may reduce ri

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• D

  digoxin and amiodarone: Interaction, Risks, and Safer

  Interaction between Digoxin and Amiodarone: major severity. Amiodarone doubles digoxin levels via P-glycoprotein inhibition.

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• D

  digoxin and thiazide-diuretic: Interaction, Risks, and Safer

  Interaction between Digoxin and Thiazide Diuretic: moderate severity. Thiazides cause hypokalemia and hypomagnesemia, which sensitize cardiac myocytes

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• D

  digoxin and verapamil: Interaction, Risks, and Safer Alternatives

  Interaction between Digoxin and Verapamil: moderate severity. Verapamil inhibits P-glycoprotein-mediated tubular secretion of digoxin and adds

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• D

  diltiazem and simvastatin: Interaction, Risks, and Safer

  Interaction between Diltiazem and Simvastatin: major severity. Diltiazem inhibits CYP3A4 metabolism of simvastatin, increasing exposure and ris

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• D

  diltiazem and tacrolimus: Interaction, Risks, and Safer

  Interaction between Diltiazem and Tacrolimus: moderate severity. Diltiazem inhibits CYP3A4 metabolism of tacrolimus, raising blood concentrations

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• D

  domperidone and fluconazole: Interaction, Risks, and Safer

  Interaction between Domperidone and Fluconazole: major severity. Fluconazole inhibits CYP3A4, raising domperidone exposure and additive QT-interv

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• E

  erythromycin and simvastatin: Interaction, Risks, and Safer

  Interaction between Erythromycin and Simvastatin: major severity. Erythromycin is a strong CYP3A4 inhibitor that markedly increases simvastatin ex

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• E

  erythromycin and statin: Interaction, Risks, and Safer

  Interaction between Erythromycin and Statin: major severity. Erythromycin inhibits CYP3A4, increasing exposure of simvastatin, lovastatin, an

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• E

  erythromycin and theophylline: Interaction, Risks, and Safer

  Interaction between Erythromycin and Theophylline: moderate severity. Erythromycin inhibits CYP3A4 metabolism of theophylline, raising serum concentra

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• E

  erythromycin and warfarin: Interaction, Risks, and Safer

  Interaction between Erythromycin and Warfarin: moderate severity. Erythromycin inhibits CYP3A4 and CYP1A2 metabolism of warfarin and disrupts gut

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• E

  everolimus and ketoconazole: Interaction, Risks, and Safer

  Interaction between Everolimus and Ketoconazole: major severity. Ketoconazole strongly inhibits CYP3A4 and P-glycoprotein, increasing everolimus

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• F

  fluconazole and phenytoin: Interaction, Risks, and Safer

  Interaction between Fluconazole and Phenytoin: moderate severity. Fluconazole inhibits CYP2C9 and CYP2C19, the principal enzymes metabolizing phen

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• F

  fluconazole and tacrolimus: Interaction, Risks, and Safer

  Interaction between Fluconazole and Tacrolimus: major severity. Fluconazole inhibits CYP3A4-mediated metabolism of tacrolimus, substantially inc

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• F

  fluconazole and warfarin: Interaction, Risks, and Safer

  Interaction between Fluconazole and Warfarin: major severity. Fluconazole inhibits CYP2C9 and CYP3A4, the principal enzymes metabolizing warfa

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• F

  fluoxetine and tamoxifen: Interaction, Risks, and Safer

  Interaction between Fluoxetine and Tamoxifen: major severity. Fluoxetine is a strong CYP2D6 inhibitor and reduces conversion of tamoxifen to i

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• F

  fluvoxamine and theophylline: Interaction, Risks, and Safer

  Interaction between Fluvoxamine and Theophylline: major severity. Fluvoxamine potently inhibits CYP1A2, the principal enzyme metabolizing theophyl

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• F

  furosemide and gentamicin: Interaction, Risks, and Safer

  Interaction between Furosemide and Gentamicin: moderate severity. Loop diuretics potentiate aminoglycoside ototoxicity through additive cochlear d

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• F

  furosemide and lithium: Interaction, Risks, and Safer

  Interaction between Furosemide and Lithium: moderate severity. Loop diuretics reduce sodium reabsorption, leading to compensatory increased pro

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• G

  gemfibrozil and repaglinide: Interaction, Risks, and Safer

  Interaction between Gemfibrozil and Repaglinide: major severity. Gemfibrozil and its glucuronide inhibit CYP2C8 and OATP1B1, raising repaglinide

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• G

  gentamicin and vancomycin: Interaction, Risks, and Safer

  Interaction between Gentamicin and Vancomycin: major severity. Both drugs cause direct nephrotoxicity through proximal tubular injury, and gent

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• H

  haloperidol and methadone: Interaction, Risks, and Safer

  Interaction between Haloperidol and Methadone: major severity. Both drugs prolong the QT interval through blockade of cardiac potassium channel

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• I

  ibuprofen and aspirin: Interaction, Risks, and Safer Alternatives

  Interaction between Ibuprofen and Aspirin: moderate severity. Both NSAIDs increase bleeding risk and reduce aspirin's cardioprotective effect.

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• I

  ibuprofen and lisinopril: Interaction, Risks, and Safer

  Interaction between Ibuprofen and Lisinopril: moderate severity. NSAIDs reduce ACE inhibitor effectiveness and worsen renal function.

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• I

  indomethacin and triamterene: Interaction, Risks, and Safer

  Interaction between Indomethacin and Triamterene: major severity. NSAIDs reduce renal prostaglandin-dependent perfusion while triamterene blocks d

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• I

  irbesartan and spironolactone: Interaction, Risks, and Safer

  Interaction between Irbesartan and Spironolactone: moderate severity. Both agents reduce aldosterone-mediated potassium excretion, leading to additive

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• I

  isoniazid and phenytoin: Interaction, Risks, and Safer

  Interaction between Isoniazid and Phenytoin: moderate severity. Isoniazid inhibits CYP2C19 and CYP2C9, slowing phenytoin metabolism, with the ef

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• I

  itraconazole and midazolam: Interaction, Risks, and Safer

  Interaction between Itraconazole and Midazolam: major severity. Itraconazole strongly inhibits CYP3A4, increasing oral midazolam exposure 6-10 f

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• K

  ketoconazole and midazolam: Interaction, Risks, and Safer

  Interaction between Ketoconazole and Midazolam: major severity. Ketoconazole is a potent CYP3A4 inhibitor that increases oral midazolam AUC up t

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• K

  ketoconazole and tacrolimus: Interaction, Risks, and Safer

  Interaction between Ketoconazole and Tacrolimus: major severity. Ketoconazole strongly inhibits CYP3A4 and P-glycoprotein, causing major increase

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• L

  lamotrigine and valproate: Interaction, Risks, and Safer

  Interaction between Lamotrigine and Valproate: major severity. Valproate inhibits UGT1A4-mediated glucuronidation of lamotrigine, more than dou

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• L

  levodopa and metoclopramide: Interaction, Risks, and Safer

  Interaction between Levodopa and Metoclopramide: major severity. Metoclopramide is a central dopamine D2 receptor antagonist that opposes the the

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• L

  levothyroxine and calcium: Interaction, Risks, and Safer

  Interaction between Levothyroxine and Calcium: moderate severity. Calcium binds levothyroxine in gut, reducing absorption by up to 30%.

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• L

  levothyroxine and iron: Interaction, Risks, and Safer

  Interaction between Levothyroxine and Iron: moderate severity. Iron binds levothyroxine in gut, reducing absorption. Reviewed by iMedic's medical editorial...

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• L

  levothyroxine and omeprazole: Interaction, Risks, and Safer

  Interaction between Levothyroxine and Omeprazole: moderate severity. Reduced gastric acidity from proton pump inhibition impairs dissolution and abso

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• L

  linezolid and mirtazapine: Interaction, Risks, and Safer

  Interaction between Linezolid and Mirtazapine: major severity. Linezolid's MAO-A inhibition combined with mirtazapine's serotonergic activity c

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• L

  linezolid and pseudoephedrine: Interaction, Risks, and Safer

  Interaction between Linezolid and Pseudoephedrine: major severity. Linezolid is a reversible MAO inhibitor; co-administration with sympathomimetic

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• L

  linezolid and serotonergic-agent: Interaction, Risks, and Safer

  Interaction between Linezolid and Serotonergic Agent: major severity. Linezolid is a reversible non-selective MAO inhibitor; combination with SSRIs, S

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• L

  linezolid and sertraline: Interaction, Risks, and Safer

  Interaction between Linezolid and Sertraline: major severity. Linezolid is a reversible non-selective MAO inhibitor; combination with serotone

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• L

  linezolid and venlafaxine: Interaction, Risks, and Safer

  Interaction between Linezolid and Venlafaxine: major severity. Linezolid is a reversible MAO inhibitor; combined with serotonergic SNRIs it can

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• L

  lisinopril and lithium: Interaction, Risks, and Safer

  Interaction between Lisinopril and Lithium: major severity. ACE inhibitors reduce renal lithium excretion by decreasing glomerular filtratio

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• L

  lithium and ibuprofen: Interaction, Risks, and Safer Alternatives

  Interaction between Lithium and Ibuprofen: major severity. NSAIDs reduce renal lithium clearance, raising lithium levels into toxic range.

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• L

  lithium and ramipril: Interaction, Risks, and Safer Alternatives

  Interaction between Lithium and Ramipril: moderate severity. ACE inhibitors reduce renal blood flow and lithium clearance via decreased glome

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• L

  lithium and thiazide-diuretic: Interaction, Risks, and Safer

  Interaction between Lithium and Thiazide Diuretic: major severity. Diuretics reduce lithium clearance, raising levels. Reviewed by iMedic's medical...

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• M

  meropenem and valproate: Interaction, Risks, and Safer

  Interaction between Meropenem and Valproate: major severity. Carbapenems lower valproate plasma concentrations by 60–90% within 24–48 hours,

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• M

  metformin and alcohol: Interaction, Risks, and Safer Alternatives

  Interaction between Metformin and Alcohol: moderate severity. Alcohol increases lactic acidosis risk in metformin users, especially with binge

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• M

  metformin and contrast-dye: Interaction, Risks, and Safer

  Interaction between Metformin and Contrast Dye: major severity. Risk of contrast-induced nephropathy and lactic acidosis in metformin users.

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• M

  metformin and iv-contrast: Interaction, Risks, and Safer

  Interaction between Metformin and Iv Contrast: major severity. Risk of lactic acidosis with renal impairment from contrast.

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• M

  metformin and trimethoprim: Interaction, Risks, and Safer

  Interaction between Metformin and Trimethoprim: moderate severity. Trimethoprim inhibits the renal organic cation transporter OCT2 and MATE1, reduc

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• M

  methotrexate and naproxen: Interaction, Risks, and Safer

  Interaction between Methotrexate and Naproxen: major severity. NSAIDs inhibit renal prostaglandin synthesis and compete for tubular secretion,

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• M

  methotrexate and omeprazole: Interaction, Risks, and Safer

  Interaction between Methotrexate and Omeprazole: moderate severity. Proton pump inhibitors reduce renal clearance of methotrexate via inhibition of

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• M

  methotrexate and trimethoprim: Interaction, Risks, and Safer

  Interaction between Methotrexate and Trimethoprim: major severity. Both inhibit folate metabolism — risk of severe pancytopenia.

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• M

  metoclopramide and olanzapine: Interaction, Risks, and Safer

  Interaction between Metoclopramide and Olanzapine: moderate severity. Both drugs are dopamine D2 antagonists; combined use increases the risk of extra

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• M

  metoprolol and verapamil: Interaction, Risks, and Safer

  Interaction between Metoprolol and Verapamil: major severity. Both reduce heart rate and AV conduction — risk of bradycardia, heart block.

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• M

  metronidazole and warfarin: Interaction, Risks, and Safer

  Interaction between Metronidazole and Warfarin: major severity. Metronidazole inhibits CYP2C9-mediated metabolism of the more potent S-enantiome

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• M

  miconazole and warfarin: Interaction, Risks, and Safer

  Interaction between Miconazole and Warfarin: major severity. Even topical/oral-gel miconazole inhibits CYP2C9 and CYP3A4, markedly potentiati

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• M

  moclobemide and pethidine: Interaction, Risks, and Safer

  Interaction between Moclobemide and Pethidine: major severity. Pethidine has serotonergic activity and combined with the MAO-A inhibitor moclob

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• N

  nitrates and sildenafil: Interaction, Risks, and Safer

  Interaction between Nitrates and Sildenafil: major severity. Severe hypotension risk — both lower blood pressure dramatically.

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• O

  ondansetron and tramadol: Interaction, Risks, and Safer

  Interaction between Ondansetron and Tramadol: moderate severity. Ondansetron blocks 5-HT3 receptors central to tramadol's analgesic action and ma

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• O

  oral-contraceptive and rifampicin: Interaction, Risks, and Safer

  Interaction between Oral Contraceptive and Rifampicin: major severity. Rifampicin induces hepatic enzymes, dramatically reducing contraceptive effectiv

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• P

  paracetamol and alcohol: Interaction, Risks, and Safer

  Interaction between Paracetamol and Alcohol: moderate severity. Chronic heavy alcohol use induces CYP2E1, increasing paracetamol's hepatotoxic m

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• P

  phenytoin and valproate: Interaction, Risks, and Safer

  Interaction between Phenytoin and Valproate: moderate severity. Valproate displaces phenytoin from albumin and inhibits its metabolism, raising

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• P

  phenytoin and voriconazole: Interaction, Risks, and Safer

  Interaction between Phenytoin and Voriconazole: major severity. Phenytoin induces CYP2C19 and CYP3A4 metabolism of voriconazole (reducing antifu

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• P

  phenytoin and warfarin: Interaction, Risks, and Safer

  Interaction between Phenytoin and Warfarin: major severity. Phenytoin causes biphasic effects: initial inhibition of CYP2C9 raises INR, foll

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• P

  prednisolone and rifampicin: Interaction, Risks, and Safer

  Interaction between Prednisolone and Rifampicin: moderate severity. Rifampicin is a potent CYP3A4 inducer, accelerating corticosteroid metabolism an

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• Q

  quetiapine and rifampicin: Interaction, Risks, and Safer

  Interaction between Quetiapine and Rifampicin: major severity. Rifampicin is a potent CYP3A4 inducer that reduces quetiapine plasma concentrati

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• Q

  quinolone and sucralfate: Interaction, Risks, and Safer

  Interaction between Quinolone and Sucralfate: moderate severity. Sucralfate contains aluminum that chelates fluoroquinolones in the GI tract, red

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• R

  rifampicin and tacrolimus: Interaction, Risks, and Safer

  Interaction between Rifampicin and Tacrolimus: major severity. Rifampicin is a potent inducer of CYP3A4 and P-glycoprotein, dramatically reduci

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• R

  rifampicin and warfarin: Interaction, Risks, and Safer

  Interaction between Rifampicin and Warfarin: major severity. Rifampicin induces CYP2C9, CYP3A4, and CYP1A2, accelerating metabolism of both w

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• R

  ritonavir and rivaroxaban: Interaction, Risks, and Safer

  Interaction between Ritonavir and Rivaroxaban: major severity. Ritonavir is a strong inhibitor of both CYP3A4 and P-glycoprotein, the dual elim

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• R

  ritonavir and salmeterol: Interaction, Risks, and Safer

  Interaction between Ritonavir and Salmeterol: major severity. Ritonavir potently inhibits CYP3A4 metabolism of salmeterol, producing markedly

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• R

  ritonavir and sildenafil: Interaction, Risks, and Safer

  Interaction between Ritonavir and Sildenafil: major severity. Ritonavir is a potent CYP3A4 inhibitor that increases sildenafil exposure up to

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• S

  sacubitril-valsartan and spironolactone: Interaction, Risks, and

  Interaction between Sacubitril Valsartan and Spironolactone: moderate severity. Both drugs raise serum potassium — sacubitril/valsartan via angiotensin recep

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• S

  sertraline and sumatriptan: Interaction, Risks, and Safer

  Interaction between Sertraline and Sumatriptan: moderate severity. Both increase serotonergic activity — sertraline by blocking 5-HT reuptake, suma

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• S

  sertraline and tramadol: Interaction, Risks, and Safer

  Interaction between Sertraline and Tramadol: major severity. Sertraline inhibits CYP2D6 (reducing analgesic activation of tramadol) while com

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• S

  sildenafil and tamsulosin: Interaction, Risks, and Safer

  Interaction between Sildenafil and Tamsulosin: moderate severity. Both drugs cause vasodilation; PDE-5 inhibition combined with alpha-1 blockade c

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• S

  simvastatin and verapamil: Interaction, Risks, and Safer

  Interaction between Simvastatin and Verapamil: major severity. Verapamil inhibits CYP3A4 metabolism of simvastatin, raising plasma levels and t

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• S

  spironolactone and trimethoprim: Interaction, Risks, and Safer

  Interaction between Spironolactone and Trimethoprim: moderate severity. Trimethoprim blocks distal tubular sodium channels in a manner similar to amilor

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• S

  ssri and maoi: Interaction, Risks, and Safer Alternatives

  Interaction between Ssri and Maoi: major severity. Risk of fatal serotonin syndrome. Reviewed by iMedic's medical editorial team.

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• S

  ssri and nsaid: Interaction, Risks, and Safer Alternatives

  Interaction between Ssri and Nsaid: moderate severity. Combined increases gastrointestinal bleeding risk by 4-5x. Reviewed by iMedic's medical editorial team.

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• S

  ssri and tamoxifen: Interaction, Risks, and Safer Alternatives

  Interaction between Ssri and Tamoxifen: major severity. Strong CYP2D6 inhibitors among the SSRIs (paroxetine, fluoxetine) reduce convers

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• S

  ssri and tramadol: Interaction, Risks, and Safer Alternatives

  Interaction between Ssri and Tramadol: major severity. Both increase serotonin — risk of serotonin syndrome (agitation, hyperthermia, r

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• S

  ssri and triptan: Interaction, Risks, and Safer Alternatives

  Interaction between Ssri and Triptan: moderate severity. Both classes increase serotonergic activity; combined use can theoretically prec

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• S

  ssri and warfarin: Interaction, Risks, and Safer Alternatives

  Interaction between Ssri and Warfarin: moderate severity. Increased bleeding risk via platelet effects. Reviewed by iMedic's medical editorial team.

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• S

  st-johns-wort and tacrolimus: Interaction, Risks, and Safer

  Interaction between St Johns Wort and Tacrolimus: major severity. St John's wort induces CYP3A4 and P-glycoprotein, substantially lowering tacroli

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• S

  statin and fibrate: Interaction, Risks, and Safer Alternatives

  Interaction between Statin and Fibrate: major severity. Combined increases myopathy/rhabdomyolysis risk substantially, especially with g

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• S

  statin and grapefruit-juice: Interaction, Risks, and Safer

  Interaction between Statin and Grapefruit Juice: moderate severity. Grapefruit inhibits CYP3A4 — increases atorvastatin/simvastatin levels and myopa

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• S

  sulfamethoxazole and sulfonylurea: Interaction, Risks, and Safer

  Interaction between Sulfamethoxazole and Sulfonylurea: moderate severity. Sulfamethoxazole inhibits CYP2C9, reducing sulfonylurea metabolism (especially g

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• S

  sulfamethoxazole-trimethoprim and warfarin: Interaction, Risks

  Interaction between Sulfamethoxazole Trimethoprim and Warfarin: major severity. Sulfamethoxazole inhibits CYP2C9-mediated metabolism of S-warfarin and displa

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• S

  sumatriptan and venlafaxine: Interaction, Risks, and Safer

  Interaction between Sumatriptan and Venlafaxine: moderate severity. Both drugs increase serotonergic activity (triptan via 5-HT1B/1D agonism, venlaf

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• T

  tacrolimus and voriconazole: Interaction, Risks, and Safer

  Interaction between Tacrolimus and Voriconazole: major severity. Voriconazole strongly inhibits CYP3A4-mediated tacrolimus metabolism, increasing

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• T

  tramadol and warfarin: Interaction, Risks, and Safer Alternatives

  Interaction between Tramadol and Warfarin: moderate severity. Tramadol is reported to potentiate warfarin effect through unclear mechanisms po

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• V

  valproate and warfarin: Interaction, Risks, and Safer

  Interaction between Valproate and Warfarin: moderate severity. Valproate displaces warfarin from albumin binding sites and may inhibit CYP2C9 m

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• V

  venlafaxine and warfarin: Interaction, Risks, and Safer

  Interaction between Venlafaxine and Warfarin: moderate severity. Venlafaxine inhibits platelet serotonin reuptake reducing platelet aggregation,

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• V

  vincristine and voriconazole: Interaction, Risks, and Safer

  Interaction between Vincristine and Voriconazole: major severity. Voriconazole inhibits CYP3A4, increasing vincristine exposure and dramatically w

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• V

  voriconazole and warfarin: Interaction, Risks, and Safer

  Interaction between Voriconazole and Warfarin: major severity. Voriconazole strongly inhibits CYP2C9 and CYP3A4, raising S-warfarin levels and

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• W

  warfarin and antibiotic: Interaction, Risks, and Safer

  Interaction between Warfarin and Antibiotic: major severity. Many antibiotics potentiate warfarin via gut flora disruption or CYP inhibition.

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• W

  warfarin and aspirin: Interaction, Risks, and Safer Alternatives

  Interaction between Warfarin and Aspirin: major severity. Both anticoagulants — significantly increased bleeding risk, especially gastroin

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• W

  warfarin and ibuprofen: Interaction, Risks, and Safer

  Interaction between Warfarin and Ibuprofen: major severity. Ibuprofen increases bleeding risk in patients on warfarin via platelet inhibitio

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