You didn't give much to go on so it is a tricky question to ask. Everyone is different - so everyone will experience it differently. Your metabolism, body fat content, how many time you dose in a day, overall health, and activity levels. All affect meth wds. Another thing that makes it difficult to answer is what degree of withdrawl symptoms are you talking about? I'm thinking you want to know how bad it will get and how soon. You will feel symptoms within a day if you are dosing 4 times a day (this is my regimine). However, larger doses once a day and this person will be fine for about two days before symptoms are felt. Methadone is stored in the fat and takes a long time for it to leave your body. Generally, it will take several days to a week or more before you will be in full blown wd. You will be in this state for weeks. A slow and closely supervised taper is standard practice. As far as your Doctor is concerned, I'd like to kick him in the jewels. Cutting your dose in half in one shot is not only cruel and unethical, it borders on malpractice. I would ask him if he has a license to administer methadone, because what he did to you is wrooonggg! Not only will the degree you suffer from rapid onset wd, your pain levels will cripple you because it's taken a long time for your pain receptors to adjust to the presence of a very powerful exogenous pain medication. Coming off must be gradual over a long period of time at low levels each time so your body can readjust slowly as well. You should not be dropping any greater than 10% at a time, with 3 - 6 week intervals. That should be your decision. I know what you are going through, or judging from the age of your post, went through. I am a chronic pain patient for 24 years on Methadone for 8 of those years. My medical team is taking me off (my choice) 5 mg a time, once a month. Addicts, say in a Methadone clinic, are not treated as kindly. Kind of like how you were treated by your Doctor. I wish you well.