Re: INR value

On 10/21/08, Abutarif, Malaz <[EMAIL PROTECTED]> wrote: > Several papers exist (mostly in the "outcomes research" area). > What I generally used in the past is to calculate the % of time a patient > remains between 1.5x to 3x. The % of time the patient stays above 3x INR is > usually correlated with increased risk of bleeding complications (use that > as a risk indicator). Below 1.5 (some Physicians use 2x) is considered > sub-therapeutic. Obviously, INR or aPTT are only useful for bleeding > complications correlation and not for other toxicities. > > Look at it this way, it's similar to driving at a speed higher than the > speed limit. It doesn't mean that if you drive higher than the speed limit > you will get into a car accident, it just means: > 1. You are at a higher probability of getting into an accident > and > 2. If you get into an accident, the consequences are greater than if you > stay within the speed limit. > > I look at 3x INR as the "speed limit" of anticoagulants. > Below 1.5x is just going too slow on a highway. OR, below 1.5x the patient > is not protected and is at a probability of getting a stroke similar to that > of placebo > > :-) > > Several old references exist that use the 2-3 or 1.5 to 3x, a more recent > one is below > > J Thromb Thrombolysis. 2008 Apr 5. [Epub ahead of print] Links > Warfarin: what are the clinical implications of an out-of-range-therapeutic > international normalized ratio?Merli GJ, Tzanis G. > > > > ___________________________ > Malaz A. AbuTarif, > B.Sc. (Pharmacy), Ph.D., G.C.P.M., M.B.A. > Principal Scientist, > Pharmacokinetics, Pharmacodynamics and Pharmacometrics > Early Clinical Research and Experimental Medicine > Schering- Plough Research Institute > 2015 Galloping Hill Rd, K-15-2-2650 > Kenilworth, NJ 07033 > Tel: (908) 740-3835, Fax: (908) 740-2916 > [EMAIL PROTECTED] > > > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] > On Behalf Of Dominik Uehlinger > Sent: Tuesday, October 21, 2008 10:23 AM > To: [email protected] > Subject: Re: [NMusers] INR value > > > Khaled Nm schrieb: > > Dear nmusers, > > > > I am looking for a reference for a maximum value for INR, byeond this > > value the drug toxicity of anticoagulatnt may occur. > > thanks for any response > > Abduljalil > > > > __________________________________________________ > > Do You Yahoo!? > > Tired of spam? Yahoo! Mail has the best spam protection around > > http://mail.yahoo.com > Dear Abduljalil, > > If only it were as simple as that! > > The major toxicity of anticoagulation is bleeding. However bleeding > episodes may even occur at normal INR levels (much more factors are > involved). There is no "secure" level, below which no bleeding occurs, > but the risk of bleeding gradually increases when the INR increases. > > The risk of bleeding we are willing to accept (i.e. the maximum INR > value) is given by the probability and seriousness of expected > thromboembolic events (risk benefit ratio). Therefore target INR values > are fixed dependent on the underlying disease: E.g. venous > thromboembolic disease: 2.5, artificial heart valves: 2.5-3, > thrombophilia: 3. > > With respect to non-bleeding toxicity of coumarins: these are largely > dose independent. > > Regards Dominik > > -- > ==================================================== > Prof. Dr. med. Dominik Uehlinger > Klinik und Poliklinik für Nephrologie und Hypertonie Universität Bern, 3010 > Bern - Inselspital Tel. +41 31 632 31 44, Fax +41 31 632 97 34 > [EMAIL PROTECTED] > > ********************************************************************* > This message and any attachments are solely for the > intended recipient. If you are not the intended recipient, > disclosure, copying, use or distribution of the information > included in this message is prohibited -- Please > immediately and permanently delete. > >