Hi Jo h,
Stalevo (50=50mg levodopa) is a three in one tablet. the three ingredients are levodopa, (50mg) carbidopa (12.5mg) and entacapone (200mg). As you can see the first two are the same as in the Sinemet your husband's been taking. So in essence Stalevo is Sinemet with Entacapone added. Entacapone increases/enhances the effectiveness of the levodopa, it prolongs the period levodopa will work. This is helpful as Levodopa is a short acting drug. It makes sense not to increase the levodopa at this early stage, Eventually the increase will happen of course , but this will be very gradual I hope, so your husband could get many good years.
Entacapone has, like any drug of course, its own side effects, but a lot of people find these acceptable.