I have noticed that SGPT (ALT) level increased, why does the level go up?

Hello Doctor,
I started to take Ezetrol tablet daily 1 for last 8 months to lower my cholesterol level as per Doctor advise.
Recently I have noticed that SGPT (ALT) level increased consistent during this period from 39 to 80. I have stopped taking this medicine from this week. Can you please shed more light on this. Why the level go up and is this effect my liver function etc.
Thank you for the prompt reply