Pain Concern
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Tramadol and Warfarin reaction?

I have been moved from Co-Codamol 30 to Tramadol for pain but a report shows it increases INR and it is important to monitor INR more closely.

It must be me but for a strange reason I have gone from 2.4, 3.8, 2.4 Just started Tramadol and my last test this week I am down to 1.8? My Range is 2.5-3.5 3.0 ideal. Found this report that confirms increase INR with Tramadol. Any ideas as to why I would drop so much?

9 Replies

What is INR??


international normalized ratio

A lower number means blood clots more quickly than expected. Prothrombin time as a ratio. For people taking the blood-thinning medication warfarin (Coumadin), results are given as a number that represents a ratio called the international normalized ratio (INR).

1 would be normal I need to clot at between 2.5 and 3.5 times that to stop me having a stroke or heart attack.


thanks for that! Hope you manage to stay within your limit. Take care. :)


What is INR and what is a normal reading? I ask because a friend of mine has just started to take Warfarin. Thanks.


Sorry I wrote that post before I saw that helpful explanation!


Apologies if I misread matters but I'm guessing from your post that you haven't been on warfarin very long. Doctors should monitor INR levels closely for any change in meds or lifestyle - warfarin is very sensitive to change. Also bear in mind that individual responses vary significantly and even if your INR rises one time to a specific stimuli, the next time it may drop.

For example, I stopped smoking early summer and you'd expect INR to rise but mine dropped. Another time it went through the roof taking an oral anti-fungal which had been prescribed because of its low rate of warfarin interaction. And, by the way, I tend to be pretty stable on warfarin!

As for this report, a handful of patients out of many thousands (probably 100s of 1000s) had a reaction. You're more likely to have an issue from eating a portion of spinach (up) or drinking a glass of cranberry juice (down). There are newer alternatives which are less sensitive, don't require INR tests and have same dose for everyone. They're not suitable in all circumstances (mainly because the effects cannot be reversed as easily as warfarin) but it is worth a discussion with your prescriber, especially if you're on anticoagulants for life.

Best of luck


I have been on Warfarin since 1992 and seen many ups and downs in my INR but it just seems strange that I have dropped so much since I started taking Tramadol. When it seems that it should usually be the opposite. I do have a habit of bucking the trend. I have woke up in surgery twice when on a general and having an Iodine allergy has made any heart work mean local anaesthetic is my only way forward. I seem to get better pain relief from the drugs that make my body produce the opiate effect. Were as Morphine does not.

I was in A&E with a collapsed Lung in 2008 and was given a large number of morphine injections which should of knocked me out but I was asked to speak to a group of students who asked me how I felt etc. The consultant then asked them to estimate how much morphine I had been given from what they had seen? They all totally understated my dose.

I am having INR tests every 2 weeks at the moment.

Be Well


Crikey! I thought I went against the trend. Given your INR changes so much, have you asked about alternatives to warfarin? I'm starting Xarelto on Monday; had to wait until fully recovered from surgery and wouldn't be a viable option if expected to need any further ops.


Only problem now is I also have Restrictive lung disease with fibrosis and few other things, so if I have a lung bleed I need a thinner with an antidote were the others have a 12 hour half life. I understand that they have had positive tests so far on the new ones so maybe in time.


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