I am dealing with the same question right now.
My level is at 118 and my Dr cut me from 2X 6MP per day to 1X (50 MG).
He wants me back in a month to re-test my bloodwork. If my ALT levels are not decreasing, he said I will have to stop taking it.
I am very upset about this since I am 100% good on my meds right now.
Also - I am getting a 2nd opinion since I am very concerned about my liver!