I dont have a kid that has taken that medication, but I have taught kids that have been on it ( Spec. Ed. Teacher).
As for the medications taking-- I would try a few things (antibiotics are bitter so most kids dont like taking them unless they are hidden in something else).
1. I would mix in with something that EVERYONE eat/drink but only his has the medication, then he will not feel singled out.
2.If he is old enough explain what it is for and why taking it
3. ask for it flavored by the pharmacy- they can make stuff taste SO much better!
4. Potentially- could he take it AT school? Sometimes kids do better going to the nurse and takign it since it is treat to get out of the classroom
If it is a taste thing, not to hard to get around. If it is just a plain defiance problem--them you need to have some sort of system (depending on your home system or school system) that is positive for taking it- a reward chart, a small treat or trinket, extra time before bed, movie,etc. Especially at the beginning.
They DO make a patch version--- is your DC old enough to use that??
Most of the kids I worked with that took it were dx w/ Austism Spectrum disorders. They took it to improve sleep and moderate moods. The side effects we saw at school were sleepiness, sluggishness, dry mouth, and low blood pressure. We saw reduced anger/aggression in most of the kids that took it-- a few it did not seem to effect (at the dose they were given).
Again, I do not know the insides of the family dynamics of most of the families I worked with-- but often it was a medicine that was used after a few others had been tried. The kids I worked with took it long term.
I would suggest keeping a journal. Both of a few days before and then afterward on his behaviors/sleeping/eating patterns. It will be helpful to see any trends (reduced eating, less sleep, more raging or anger). That sometimes in the moment or after a week it is hard to definitively say 'YES I see a big improvement or little gains.' Then if you do see side effects, you can weight the pros/cons of continuing it.
As for explaining it to him.. try going to route that a lot of people take medicine, sometimes even when they are not sick. (give examples of diabetes, headaches, blood pressue--whatever he may be familiar with) and that his medicine is to help his moods (or how ever you explain it to him). If you dont make a big deal he most likely will not either (depending on his age). Simply keep it as a medicine that helps him, matter of factly. If he is young this is often enough. If he is old enough and then sees an improvement in his actions, he will be more motivated to keep taking it.
HTH. I dont have kids that take it, but have watched families agonize over behavioral medication use. Really- I see it as just one of a helpful tool to help a legitimate issue in a person being socially/emotionally involved in daily life. It takes many different things together- medication is only one piece. ( therapies, supportive environment, behavior plans, etc) The stigma that society places on such things is sad since there are so many people (kids/adults) that could benefit.