Demands for a panda can be everything, way more than what a neurotypical or even non-PDA autistic would intuitively assume.
The name PDA in itself is misleading, a bit.
Yes, it's the most visible symptom, but not the cause.
It's- at least in my own personal experience and some other pandas - more about the expectations of people around us and our autonomy.
(that's why it's Also sometimes called "Pervasive Drive for Autonomy")
We kinda need to be in control of ourselves at all time. We don't want people to decide who we are and what we do. Up to a paradoxical level where doing what people want can cause us stress and these people don't even have to be anyone else than ourself.
That'a why I dont like gifts. People expect me to be happy. And even if it's a good gift... I just don't like it how everybody around me expect me to be happy.
Understanding what each panda sees as something to avoid is a tough task, as my girlfriend could tell you. But if one is accepted for differences and compromises are seen as good enough, then everybody can be a bit happier.
Example: I cannot (unless I really force myself) put the garbage in the garbage bin. I always make a few piles sorted by material on the table next to the bin. My gf does not think "This stupid person, never putting the garbage where it belongs", but "Nice, Person has cleaned up the room and put the garbage here for me to throw away". Something that is called a "demand compromise" in literature.
I recommend to watch the following video:
https://youtu.be/_abB44rPqEM
(keep in mind that he is one single autistic individual and PDA is a spectrum in a spectrum.)
I can also recommend some videos of "I'm Autist, now what?"
In general I may suggest to seek resources of adult pandas. Medical literature, especially on PDA, is mostly from the outside with nobody ever listening to the actual autistic individuals.
And surely much of what they tell from their live is also applicable to children.
Regarding the meds, yeah, I thought something along the lines could be the case; that's why I initially didn't want to recommend too much from my side: I simply don't know all the chemicals and therapies etc; all my knowledge comes from adults.
All my meds were just the "usual" stuff (cough, fever, pain)
Therefore: I guess I cannot help you on your initial question at all, but may this text and these videos will give you a better understanding on what different pandas might see as demands.