Were you not given any advice on how to go about it? Could you ask a Parkinson nurse? Or the PUK helpline?
Just to help you understand what is involved (and the change=over should not be too traumatic) here are a few explanations:
Stalevo is a combination drug, it contains three ingredients: carbidopa, levodopa and entacapone. It was created to simplify taking the tablets.
Sinemet contains two ingredients: carbidopa and levodopa.
Stalevo is really just Sinemet with entacaopone added. You could take a Sinemet tablet and an Entacapone tablet instead of the single combination tablet Stalevo. I presume your husband took Stalevo tablets that contained 75mg levodopa (the strength of the other two ingredients is not so imoportant, all Stalevo tablets contain 200mg Entacaopone) three times a day.. Switching to Sinemet (containing 75 mg Levodopa) on its own would have the same effect as scaling down total daily levodopa intake., that is why he will have to increase the number of times he will take Sinemet to five times a day.to stay on the same level of drug treatment . Entacapone does not work on its own, it enhances the levodopa, it makes it work longer, but the effect is similar to an increase in levodopa of about 30%. I hope this give you some idea of what is going on.