Wellbutrin is not a weight-based medication although I do not know what the parameters are for treating children. For adults, 150mg is considered the starting dose.
In the very beginning it is no big deal to stop the meds if there is a problem. If he takes 150mg or even more for a month+ then doing a titration off (like 1 every other day or whatever) may be a good idea.
Or if it makes you more comfortable - you can give him one every other day a couple of times to come off more gradually.
The main concern with Wellbutrin is the risk of having seizures as a side effect. I am pretty sure that this is the main concern with stopping cold turkey. The seizures are more of an issue for people with a history (personal or family) of a seizure disorder. The medication lowers the seizure threshold in the brain (think of it as a wall that lowers as certain medications are increased - at some point the wall will be low enough for a seizure to break through).
Taking it at higher doses (the max dose/day is 450mg) increases the risk a bit, and so does drinking alcohol, etc.
This side effects is not common, BTW, but it does exist.
BTW - I take Wellbutrin 300mg along with Prozac and Focalin. I LOVE Wellbutrin and other than some mild side effects (dizzy and anxiety-related) it has worked like a charm.
There are other forms of Wellbutrin, such as Wellbutrin SR. This comes in 150 mg and can be cut in half. After cutting the tablet it starts to lose some potency, but it will still help - especially if you are just doing it to wear up to the higher dose. However, it has a shorter duration of effect than the XL form so it typically is given twice a day. This is what I take (150mg twice day) because the 300mg Wellbutrin XL caused some somewhat severe stomach discomfort. I had to set an alarm on my cell phone to remind me to take the second dose because I would forget half the time if I didn't....
You can keep this alternative in mind in case the 150mg causes some significant side effects. MOST side effects wear off within a couple of weeks or so. And Wellbutrin is a bit different from other antidepressants in that you (he) will probably notice a difference the first day. It will take 4 weeks or so to reach maximum effect, but he may get some benefit right away. I did.
Good luck and Happy Holidays!!
Got a reply from the doc today about my son taking Wellbutrin XL. He stated that I could start him on the 150 mg. dose without titrating him up and if things did not improve within the next two weeks, I could stop the dose cold turkey. My son is 10 years old. Has anyone started their child on the 150 mg. XL dose and had to stop it abruptly? The doc doesn't seem concerned over withdrawal side effects. dad243239433.7227777778My daughter began taking Welbutrin when she was 8. She takes two 75 mg doses daily. As I remember it, when she started taking it, we were instructed to give her 1/2 tablet daily to start with, and her dose was titrated by adding an additional 1/2 tablet every few days until she was taking the full dose.