It's the stuff in Tylenol, though I don't know what it's called in Japan. The painkiller that isn't asprin.
I think it might be too late for poor drone now =/
<edit>
Here I found this online:
Paracetamol as it's known in the UK has the generic name of acetaminophen. It's marketed as Tylenol in the US. You can often find Tylenol in regular Japanese pharmacies. If not then ask the doctor for acetaminophen.
I said acetaminophen in my post! The part that I added under <edit> soon after posting.
There's asprin, and then for people who get a stomach ache when they take asprin, there's the other major painkiller. The "un-asprin", the painkiller of many names. Generic name acetaminophen, Paracetamol in the UK, Panadol in New Zealand, Tylenol in North America.