I'm not sure what a safe drug is. The fact is these are all situation dependent. Peanuts are safe, but not to someone with a peanut allergy. Etc. My mom has not responded well to an additional 100mg of Sinemet. She appears to be suffering some withdrawal symptoms by its later decrease. Dopamine agonists have been shown to cause addiction/withdrawal. Dompanine enhancing drugs have been shown to cause addiction/withdrawal. Logic would tend to indicate that Sinemet could exhibit similar charachteristics at any dosage on par with a dosage that would similarly be thought to have beneficial effects. We may not have a peer reviewed study that indicates Sinemet can cause addiction/withdrawal, but it certainly seems plausible. We can't make all our decisions on scientific studies anyway. But we can try things and test correlations. The problem is the doctors are biased that their FDA approved medicines will ever be the root of negative effect-correlations, and its the last thing they look for. Even when all the evidence points otherwise.