Pre op,,,the nurses have the primary job. After the anes. doc sees the pt, he leaves an order for a light pre op sedative, usually Versed/Fentanyl.
We normally give it, but sometimes they push it.
Preop antibiotics, ordered by the surgeon, are left to us to start at the correct time.
In the OR.....anything IM/IV is by the anesthesiologist. The circulator (RN) can, and does help. But it's all up to them. Hanging blood too.
On the field.....shared responsibility. The RN circulator obtains the correct medication (usually locals, various eye drops, etc) and then transfers them to the sterile field. The circulator holds the bottle, so the scrub can see the label, including expiration date, and we both speak out loud so all are in the loop. The scrub then labels the medication container, and syringe, and hands off to the surgeon, saying out loud again, what the med is, strength, etc.
Many of our medication bottles are sterile, which eliminates one possible problem of confusion. This eliminates putting the med in yet another container before reaching the pt.
Some meds, especially those with Epi, etc, we also make sure the anesthesiologist is informed about the med the surgeon is injecting.