Effect On Warfarin Action

Drug Class

Subclass

Drug Name

Onset

Effect on Warfarin action

Cephalosporins

Cefazolin

Delayed

Increased

Quinolones

Nalixidic acid,Ofloxacin, Ciprofloxacin

Delayed

Increased

Macrolides

Azithromycin,Clarithromycin, Erythromycin

Delayed

Increased

Fluoroquinolones

Gatifloxacin,Levofloxacin

Delayed

Gatifloxacin - increase Levofloxacin - **

Tetracycline Agents

Minocycline,Tetracycline

Delayed

Increased

Sulphonamide

Co-trimoxazole, Bactrim, Metronidazole

Delayed

Increased

Antibiotics

Drug Class

Subclass

Antifungals (azoles)

NSAIDs

Drug Name

Onset

Effect on Warfarin Action

Ketoconazole,Itraconazole Miconazole

Delayed

Increased

Diclofenac, Ibuprofen, Indomethacin,Ketorolac, Mefenamic acid,Meloxacam,Naproxen

Delayed

Increased

Analgesics

Antacids

COX-2 Inhibitors

Celecoxib,Rofecoxib

Opoids

Tramadol

Delayed

Increased

Cimetidine

Delayed

Increased

Famotidine

Not Specified

NONE

Omeprazole, Rantidine

Delayed

Increased

Delayed

CarbamezapineDecreased Valproic Acid -

H2 Blockers PPI

Antiepileptic

Celecoxib -Delayed

Carbamazepine,Valproic Acid

RofecoxibRapid

Increased

Drug class

Subclass

Anti-TB

Drug Name

Onset

Effect on Warfarin action

Rifampicin

Delayed

Decreased

Isoniazid

Delayed

Increased

Anti-Thryoid

PropylThiouracil,Potassium Iodide, Methimazole

Barbituates

Phenobarbital

Delayed

Decreased

Contraceptives

Levonorgestrel

-

-

Diuretics

Frusemide,Metolazone

Not Specified

Metolazone-Decreased Frusemide- None

Cholestyramine

Delayed

Decreased

Orlistat

Not Specified

**

Statins

Lovastatin, Rosuvastatin, Simvastatin

Delayed

Increased

Fibrates

Fenofibrate, Gemfibrozil

Delayed

Increased

Dyslipidemic Agents

Drug class

Hormones

Subclass

Onset

Effect on Warfarin action

Androgens

Danazol,Testosterone

Delayed

Danazol Decreased TestosteroneIncreased

Progestins

Norethisterone Medroxy-progesterone

Delayed

**

Estrogen

Oestradiol,Oestrogens (Conjugated & Esterified)

Delayed

Decreased

AntiEstrogen

Tamoxifen

Delayed

Increased

Diabetes Mellitus (?)

Glucagon

Delayed

Increased

Thyroxine, Antithyroids

Delayed

Thyroxine -Increased AntithyroidDecreased

Azathioprine

Delayed

Decreased

-

Immunosuppresants

Drug name

Drug class

Subclass

Drug name

Onset

Effect on Warfarin action

Anti-Psychotics

Qutiapine

Delayed

OlanzapineNone QuitiapineIncreased

Antiplatelets

Aspirin, Clopidogrel, Ticlopidine Dipyridamole

Delayed

Increased

Fluvoxamine,Fluoxetine,Sertraline

Delayed

Increased

Citalopram

Not Specified

NONE

SSRI Tri-Cyclic Antidepressants

Dothiepin,Nortriptyline, Amitriptyline

Prostate

Flutamide,Tolterodine

Anticancer

Etoposide,Fluorouracil, Gemcitaine,Mercaptopurine,Mesna

Increased Delayed

Increased

Drug Name

Onset

Effect on Warfarin Action

DMARDs

Sulphasalazine,Methotrexate

-

-

Anti-arrhythmic drugs

Quinidine, Propafenone

Delayed

Increased

Drug Class

Subclass

Not Specified Specified agents may interact with each other in a clinically

C

Monitor Therapy

significant manner. Benefits should outweigh the risk. Dosage adjustments of one or both agents may be needed. Patient assessment must be conducted to determine if the

D

Consider Dosage Adjustment

benefits outweigh the risk. Specific actions must be taken, such as monitoring, empiric dosage changes, choosing alternative agents. Data demonstrates that the specified agents may interact

X

Avoid combination use

with each other in a clinically significant manner. Risks usually outweigh the benefits. Agents of this category are considered contraindicated.