The only bad effects of methadone that comes to mind are DEATH by overdose usually due to poly drug abuse.
Not getting enough mgs. to keep you from being uncomefortable
Going to a crappy clinic
Not being close to even a crappy clinic [I drive almost 180 miles r/t to closest clinic]
Having to give observed urines
Getting caught with a dirty urine
Being on a clinic that will not permit you to take a drug for pain even if you had all your teeth pulled and the
dentist gave you the Rx
Going 7 days a week in the beginning, to dose
Most jails will not dose you if you get arrested
PAYING all that money each week [me & hubby have paid out over 300k in our years to methadone clinics]
WORST THING When you are on a private clinic and they have a no money no dose policy
other than those few things on the plus side methadone saved my life