I agree with everyone here. as usual.

The methadone will help. It's a very small dose.

I don't know what else you take, but I've been on methadone since 1990 or so, and been from 10-15mg/day, up to a 100, now settled at 50-60 mg/day.
With other meds in the cocktail.

I wish you the best with you new med.
At that dose, side effects shouldn't even be noticeable.
The dose I take now, and being less active than I used to be, I need to take Miralax, (Just a little) to well, keep things moving...

Feel Better!

Pete
asb