When I started taking prozac, my pdoc said my dose was probably gonna be somewhere between 10 & 40 mg (definitely not over 60 or 80). over the past 10 years, i've gone up and down, depending on what else I was taking. from 20 to 30 isn't that big of a leap, I don't think; I am currently holding at 20. I can tell when my dose is too high (40 mg) because my head feels cold from the inside - weird!