Download Agent Interactions Table

AGENT NAME
HERBAL
SUPPLEMENTS
Cinchona°
Coenzyme Q-10
Danshen°
Devil’s Claw°
Dong Quai
Echinacea°
Feverfew
Flaxseed°
Garlic
Ginger
Ginkgo
Ginseng
Ipriflavone
St John’s Wort
Vitamin E
IMPACT OF
INTERACTION
Decreases
anticoagulant effect
Increases risk of
excessive bleeding
Increases level of
medication in the blood
Increases effects with
potential for bleeding
Increases risk of
excessive bleeding
Increases level of
medication in the blood
Increases risk of
excessive bleeding
Reduces absorption
Increases risk of
excessive bleeding
Increases risk of
excessive bleeding
Increases risk of
excessive bleeding
Increases risk of
bleeding problems
Increases level of
medication in the blood
Alters level of
medication in the blood
Helps prevent clotting
MECHANISM OF
ACTION
LEVEL OF
DOCUMENTATION
LEVEL OF RISK
Low
____
Blood thinning agent
____
____
Affects metabolism
Low
____
Unknown
Low
____
Blood thinning agent
____
____
Affects metabolism
Low
____
Blood thinning agent
____
____
Affects level of Warfarin
in the bloodstream
Blood thinning agent
Low
____
____
____
Blood thinning agent
____
____
Blood thinning agent
____
____
____
____
____
Affects metabolism
____
____
Affects metabolism
____
____
Prevents platelet sticking
Low
Troublesome
AGENT NAME
FOODS /
BEVERAGES
Alcohol
Foods rich in
Vitamin K1
Cranberry juice
OTC
MEDICATIONS
Some NSAIDS2
Aspirin
PRESCRIPTION
MEDICATIONS
Rx NSAIDS3
Sulfa Drugs4
1
IMPACT OF
INTERACTION
MECHANISM OF
ACTION
LEVEL OF
DOCUMENTATION
LEVEL OF RISK
Decreases
anticoagulant effect
Decreases
anticoagulant effect
Increases risk of
excessive bleeding
Not clearly understood
Low
Agent in body’s natural
clotting process
Not clearly understood
Low
Dangerous
(assumes chronic use)
Dangerous
Low
Dangerous
Increases risk of
gastrointestinal
bleeding
Increases risk of
excessive bleeding
NSAIDS increase GI
irritation and impair clot
formation
Blood thinning agent
High
Life Threatening
High
Life Threatening
Increases risk of
gastrointestinal
bleeding
Increases effects with
potential for bleeding
NSAIDS increase GI
irritation and impair clot
formation
Unknown, but may be
linked to decreased
vitamin k production
High
Life Threatening
High
Life Threatening
Includes foods such as green leafy vegetables, green tea, liver, and egg yolks.
Includes Aleve, Ibuprofen, and Motrin.
3
Includes Anaprox, Anaprox DS, Ansaid, Arthrotec, Cataflam, Clinoril, Daypro, Diclofenac, Diflunisal, Dolobid, Etodolac, Feldene, Flurbiprofen, Indocin,
Indocin SR, Indomethacin, Keteprofen, Ketorolac, Lodine, Lodine XL, Mefenamic acid, Meloxican, Mobic, Nabumetone, Naprelan, Naprosyn, Naproxen,
Orudis, Oruvail, Oxaprozin, Piroxicam, Ponsel, Relafen, Sulindac, Tolectin, Tolectin DS, Tolmetin, Toradol, Voltaren, Voltaren XR.
4
Includes Bactrim DS, Bactrim SS, Cotrim DS, Cotrim SS, Erythromycin/sulfisoxazole, Gantanol, Gantrisin, Pediazole, Septra DS, Sulfatrim, Sulfamethizole,
Sulfamethoxazole, sulfisoxazole, Thiosulfil Forte, trimethoprim/sulfamethoxazole.
2
AGENT NAME
IMPACT OF
INTERACTION
MECHANISM OF
ACTION
LEVEL OF
DOCUMENTATION
LEVEL OF RISK
Macrolides5
Increases effects with
potential for bleeding
High
Life Threatening
Quinolones6
Increases effects with
potential for bleeding
High
Life Threatening
Phenytoin7
Increases effects
Inhibits metabolism.
May be linked to
decreased vitamin k
production
Unknown, but may be
linked to decreased
vitamin k production
Unknown, but may relate
to genetic metabolism
disposition
Interferes with liver
enzymes that process
warfarin
Increases blood level of
warfarin
Increases body sensitivity
to warfarin
Increases blood level of
warfarin
Low
Dangerous
High
Life Threatening
Low
(rare)
High
Life Threatening
High
Life Threatening
High
Dangerous
Barbiturates8
Tamoxifen
Danazol
Amiodarone
Anabolic
Steroids9
5
Decreases effects with
potential for dangerous
blood clot formation
Increases effects with
potential for bleeding
Increases effects with
potential for bleeding
Increases effects with
potential for bleeding
Increases effects with
potential for bleeding
Life Threatening
Includes Azythromycin, Biaxin, Clarithromycin, Dynabac, Dirithromycin, E-Mycin, Erythromycin base, EES, Erythromycin ethyl succinate, Ery-Tab, Eryc,
EryPed, Erythrocin, Erythromycin stearate, llosone, erythromycin estolate, Pediazole, erythromycin/sulfisoxazole, Tao, Troleandomycin, Zithromax.
6
Alatrofloxacin, Avelox, Cipro, Ciprofloxacin, Enoxacin, Floxin, Gatifloxacin, Levaquin, Levofloxacin, Lomefloxacin, Maxaquin, Moxifloxacin, Noroxin,
Norfloxacin, Ofloxacin, Penetrex, Sparfloxacin, Tequin, Trovafloxacin, Trovan, Trovan IV, Zagam.
7
Includes Dilantin.
8
Includes aprobarbitol, amobarbital, butabarbital, talbutal, mephobarbital, pentobarbital, secobarbital, Phenobarbital
9
Includes oxymetholone, fluoxymesterone, methyltestosterone, stanozolol
AGENT NAME
IMPACT OF
INTERACTION
Antidepressants10
Increases effects with
potential for bleeding
Increases effects with
potential for bleeding
Antifungals11
Mevacor
MECHANISM OF
ACTION
Inhibits liver enzymes
that process warfarin
when administered
systemically
LEVEL OF
DOCUMENTATION
LEVEL OF RISK
Troublesome
Dangerous
High
Dangerous
Increases effects with
Low
potential for bleeding
Quinidine
Increases effects with
High
potential for bleeding
Carbamazepine
Decreases effects with
Reduces circulating
Low
potential for dangerous
levels of warfarin
blood clot formation
Cholesterol
Decreases effects with
Reduces absorption
High
12
Drugs
potential for dangerous
blood clot formation
Thyroid
Increases effects with
Increases prothrombin
High
Hormones13
potential for bleeding
time
Rifampin
Speeds body’s
Reduces circulating
High
elimination and
levels of warfarin
decreases effects
°Indicates that, thus far, our research has identified only one source of information to verify this interaction.
10
Includes paroxetine, fluoxetine, sertraline
Includes fluconazole and miconazole
12
Includes colestipol and cholestyramine
13
Includes dessicated thyroid, liothyronine, levothyroxine
11
Dangerous
Dangerous
Troublesome
Troublesome
Troublesome
Troublesome
Source List
1. Graedon J, Graedon T
“Deadly Drug Interactions: The People’s Pharmacy Guide”
St. Martin’s Griffin, 1995
2. MayoClinic.com
Complementary and Alternative Medicine Center
“Herb and Drug Interactions: ‘Natural’ Products Not Always Safe”
December 31, 2003
3. MayoClinic.com
Drug Search – Drug information provided by Micromedex
Anticoagulants (systemic)
May 18, 1999
4. Drug Digest
Drug interactions search engine – Drug information provided by Express Scripts
No date information provided
5. Stenton SB, Bungard TJ, Ackman ML
“Interactions between Warfarin and Herbal Products, Minerals, and Vitamins: A Pharmacist’s Guide”
Can J Hosp Pharm 2001; 54:186-92