I am on Warfarin and Keppra plus a mixture of other drugs and my INR levels go up and down like a yo-yo, so just expect anything, but make sure yoiur INR is checked regularly.
I’m rather new to all the different kinds of drugs out there for MS and Keppra is the first one I’ve tried. At first my INR went sky high then when my body got used to it, it lowered again. Like you it worries me as warfarin is a funny ole drug but at least you are able to adjust it yourself. I go down to my local surgery every couple of weeks to get mine tested.Great fun, but at least they all know me now. You can always e-mail me if you wish to discuss it more.
In the mean time hope you had a very happy Christmas and have the best New Year possible.