I'm wondering--- You're on methadone, and you want to use heroin, but you don't know if you'll feel the effects?? Is that what you're asking? Depends I guess on how much methadone you're on, and how long you've been on it, and how much heroin you use... You might kills yourself trying to acheive the high you are looking for though. I wouldn't recommend it.
i wouldn't use them both at the same time, i mean why would you? they both get you high...
what is the reason for your question?
are you serious? Of course you get high when you use heroin..methadone however is something I never got high off but I suppose it's possible if you take enough..