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. Author manuscript; available in PMC: 2011 Feb 1.
Published in final edited form as: Am J Med. 2010 Feb;123(2):151. doi: 10.1016/j.amjmed.2009.07.020

Table 3.

All potential confounding factors that were considered in this study

Demographic factors
Age Calendar year Gender
Nursing home resident Race State
Chronic Diseases
Chronic kidney disease Diabetes Liver disease
Obesity Prior history of GI bleed
Drugs that could potentially increase or decrease the bleeding risk
Aspirin Histamine H-2 antagonists Proton pump inhibitors
NSAIDs
Drugs that could potentially interact with warfarin*
Acetaminophen Amiodarone Azathioprine
Azithromycin Butalbital Carbamazepine
Ciprofloxacin Clarithromycin Co-trimoxazole
Dexamethasone Diltiazem Doxycycline
Erythromycin Fluconazole Fluvoxamine
Gatifloxacin Levofloxacin Levothyroxine
Methimazole Methylprednisolone Metronidazole
Phenobarbital Phenytoin Prednisone
Primidone Quinidine Quinine
Sertraline Troglitazone Tetracycline
Trazodone Zafirlukast
Potential CYP2C9, CYP3A4, and/or CYP1A2 inhibitors or inducers†
Nefazodone Pioglitazone Verapamil
*

Based on potentially interacting drugs according to Drug Facts and Comparison (Class 1 and 2 drugs)

†

Only CYP2C9, CYP3A4, and/or CYP1A2 inhibitors or inducers that were not listed as drugs that could potentially interact with warfarin in Drug Facts and Comparison