[eropple]

> What's preventing a pill that releases a dose immediately and one after 6 hours?

Being plopped into a bath of hydrochloric acid makes this a little tricky, I am led to understand.

> Or something like a diabetic pump that dispenses medication continuously?

And this led me down a brief Google walk for what these are, and...huh, that's a really good question...

[maxerickson]

Expense and convenience (a thing with access to your blood isn't very convenient).

IV pain management often includes a button the patient can push (that releases a dose and sets a timer for the next dose). Or at least it used to, I don't know if it is still done.