Skip from Skip's pharmacy told me to start out at 1.5 mg. He said most people who quit taking it, quit because of side effects and have started out at too high of a dose. Yes, 4.5 mg is the optimal and highest dose they say to take. Some people only take 3 mg though. Good luck! As soon as mine gets here from Skip's, I'll be starting it ( again..I tried it for 3 months in 2005, but didn't notice any improvement. I think I started @ 3mg though that time.) I'm also on Copaxone too.