Warfarin Drug Interactions

 

Drugs that can Increase PT/INR

Generic Name Brand Name
Acetominophen Tylenol
Allopurinol Zyloprim
Amiodarone Cordarone
Ampicillin Amcil, Omnipen
Aspirin Ecotrin
Azithromycin Zithromax
Cefamandole Mandol
Cefazolin Ancef, Kefzol
Cefoperazone Cefobid
Cefotetan Cefotan
Cefoxitin Mefoxin
Cefprozil Cefzil
Ceftriaxone Rocephin
Celebrex Celecobix
Chloral Hydrate Noctec
Chloramphenicol Chloromycetin
Cimetidine Tagamet
Ciprofloxacin Cipro, Ciloxan
Clarithromycin Biaxin
Clofibrate Atromid-S
Danazol Danocrine
Dexamethasone Decadron
Dextrothyroxine Choloxin
Diclofenac Voltaren
Dicloxacillin Dynapen, Pathocil
Dirithromycin Dynabac
Disulfiram Antabuse
Erythromycin E-Mycin, Erc, Ery-Tab
Ethotoin Peganone
Etodolac Lodine
Fenoprofen Nalfon
Fluconazole Diflucan
Fluxymesterone Halotestin
Flubiprofen Ansaid
Fluvastatin Lescol
Gemfibrozil Lopid
Glipizide Glucotrol
Ibuprofen Advil, Motrin
Indomethacin Indocin
Irbesartan Avapro
Isoniazid Laniazid
Itraconazole Sporanox
Ketoconazole Nizoral
Ketoprofen Orudis
Ketolorac Acular, Toradol
Lansoprazole Prevacid
Levamisole Ergamisol
Levofloxacin Levaquin
Levothyroxine Synthroid
Liothyronine Cytomel
Liotrix Euthroid
Losartan Cozaar
Lovastatin Mevacor
Meclofenamate Meclomen
Mefenamic Acid Ponstel
Mephenytoin Mesantoin
Methicillin Staphcillin
Methimazole Tapazole [decreased PT also reported
Methyl Salicylate Ben-Gay
Methyltestosterone Oreton Methyl
Metroindazole Flagyl
Mezlocillin Mezlin
Miconazole Monistat
Nabumetone Relafen
Nafcillin Nafcil
Nalidixic Acid NegGram
Naproxen Alevel, Anaprox, Naprelan, Nnaprosyn
Norfloxacin Noroxin
Omeprazole Prilosec
Oxacillin Bactocill, Prostaphlin
Oxandrin Oxandrolone
Oxymetholone Anadrol 50
Oxyphenbutazon Tandearil
Oxaprozin Daypro
Pantoprazole Protonix
Pencillin [IV only]
Penicillin G Pfizepen, Pentid
Pentoxifyline Trental
Phenylbutazone Butazolidin
Phenytoin Dilantin [decrease PT also reported]
Piperacillin Pipracil
Piroxicam Feldene
Propafenone Rythmol
Propylthiouracil [many manufacturers, decrease PT also reported]
Quinidine Cardioquin
Quinine  
Simvastatin Zocor
Stanazol Winstrol
Sulfamethizole Thiosulfil Forte
Sulfamethoxazole Gantanol
Sulindac Clinoril
Sulfinpyrazone Anturane
Sulfisoxazole Ganstrisine
Tamoxifen Nolvadex
Ticarcillin Disodium Ticar
Thyroid  
Ticlopidine Ticlid
Tolmetin Tolectin
Tmp-Sulfa Bactrim, Spectra
Torsemide Demadex
Troleandomycin Tao
Vitamin E Aquasol E
Vioxx Refecoxib
Voriconazole Vfend

 

*This is not a comprehensive medication list, please check other resources

Adapted with permission from the University of Michigan anticoagulation website


Drugs that can decrease PT/INR

Generic Name Brand Name
Amobarbitol Amytal
Aminoglutethimide Cyiraden
Aprobarbitol Alurate
Barburates Seconal
Butabarbital Butisol, Butalan
Carbamazepine Tegretol
Cholestyramine Questran
Ethchlorvynol Placidly
Grisofulvin Grifuvin V, Fulvicin P/G
Haloperidol Haldol
Mephobarbitol Mebaral
Methimazole Tapazole [inc PT]
Oral Contraceptives  
Pentobarbitol Nembutal
Phenobarbitol Lumnal
Phenytoin Dilantin [inc PT]
Primidone Mysoline
Propylthiouracil [many manufacturers, inc PT]
Rifabutin Mycobutin
Rifampin Rifasin, Rimactane
Secobarbitol Seconal
Spironolactone Aldactone
Sucralfate Carafate
Trazodone Desyrel
Vitamin K  

 

*This is not a comprehensive medication list, please check other resources

Adapted with permission from the University of Michigan anticoagulation website