In Canada, generics are said to be 80% to 120% as potent as the original. A range of 40% may not affect a lot of disease, but with PD, where stability is so important, the 40% difference you might face is a high price to pay to allow the Merck buy-out of Shering Plough to be papered over as a reverse take-over, to get around the "no change of control"
legal obligation. Merck will not name the supplier or give any information of substance or reveal why the supplier was changed with no advance planning. Buying out their competitor was a package deal that somehow required throwing a supplier overboard; tough luck for the spastics that it just happened to be sinemet that got lost in the shuffling of corporate cards.