Just try not to freak yourself out. When I started Kuvan in October 2007 I was a freak about watching for side effects . I think the only side effect I’ve ever had are mild headaches. They’re far and few and I personally think the reason I get them is because sometimes I got a long time without eating food or I don’t eat enough and my level drops BUT my doctor and dietitian don’t know if that really is the reason. We don’t even know if it is related to Kuvan or not because for awhile after starting Kuvan I became somewhat of a hypochondriac lol!! Like I said, I know your worried and that’s normal. I was to, but I’m glad I gave Kuvan a try because I responded amazingly.