Methyl salicylate Warfarin

Hydroxycoumarin [1076-38-6] can be synthesized by cyclization of acetyl methyl salicylate. It is a coumatin metaboHte occurring in spoiled hay. Derivatives of 4-hydroxycoumarin such as dicoumarol [66-76-2] warfarin [81-81-2] cyclocoumarol [518-20-7] ethylbis—coumaracetate [548-00-5] and bis-4-hydroxycoumarin [25892-93-7] are synthetic blood anticoagulants (see Blood, coagulants and anticoagulants). 

Tam LS, Chan TYK, Leung WK, Critchley JAJH. Warfarin interactions with Chinese traditional medicines danshen and methyl salicylate medicated oil. 

Excessive topical applications of methyl salicylates have interactions with anticoagulants such as warfarin.69... 

Increased warfarin effects have been seen when methyl salicylate or trolamine salicylate were used on the skin. 

Methyl salicylate, in the form of gels, oil, or ointment applied to the skin, has been found to increase the effects of warfarin. Bleeding and bruising and/or raised INRs have been seen with both high " and low doses of methyl salicylate. One report described the possible additive effects of methyl salicylate oil (Kwan Loong Medicated Oil) and a decoction of Danshen (the root of Salvia miltiorrhiza) on the response to warfarin (see also Coumarins and related drugs + Herbal medicines Danshen (Salvia miltiorrhizay, p.415). A raised prothrombin time has also been reported with topical trolamine salicylate. ... 

Joss JD, LeBlond RF. Potentiation of warfarin anticoagulation associated with tq>ical methyl salicylate Ann Phamacother (2000) 34, 729-33. 

Although the evidence is limited, it appears that topical methyl salicylate and trolamine salicylate can increase the effect of warfarin. 

Case one was a 66-year-old man also taking digoxin and propanolol (Tam et al. 1995). Five days prior to admission due to melena (dark-colored feces) and chest pain, and 2 days prior to treatment, the man had self-treated with a topically applied medicated oil that contained 15% methyl salicylate. Methyl salicylate has been shown to augment the anticoagulant effect of warfarin (Chan 1995, 1998 Chow et al. 1989 Joss and LeBlond 2000 Yip et al. 1990). 

Joss, J.D., and R.F. LeBlond. 2000. Potentiation of warfarin anti-coagulaHon associated with topical methyl salicylate. Ann. Pharmacother. 34(6) 729-733. 

Tam, L.S., T.Y.K. Chan, W.K. Leung, and J. Critchley. 1995. Warfarin interactions with Chinese traditional medicines Danshen and methyl salicylate medicated oil. Intern. Med.. 25(3) 258. 

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