DON"T USE IT!! My son was on the streets using heroin and get on methadone through a clinic. Yes, it's better than shooting heroin, but there's better alternatives such as Suboxone.
They call it liquid handcuffs and it's a correct phrase. You need to get to a clinic every day, (where attracts a real good crowd looking to buy methadone), and you're addicted to methadone now.
My son, who has deotoxed himself from heroin, claims that methadone is way worse than any drug. Extremely painful and takes months to get it out of your system. His experience is that clinics also don't want to lower your dose...it's a business. The more addicts the better they do.
Sorry for the rant...it just wasn't good for my son. My opinion only. It is better than buying sh#t from a dealer on the streets.
Prayers to you and your addict.