right. schedule I have no recognized medical use in the USA.
the other schedules II-V are ranked according to both dependance and toxicity.
oxycodone isnt just a higher class because youre more likely to become dependant, but because its more likely to cause life threatening effects if abused. you could call it a lower 'therapeutic window'.
there are some interesting quirks in scheduling:
codeine for example
in some cough syrups its schedule V and actually available over the counter. actually its behind the counter but you dont have to have a prescription. there is a considerable amount of liability on the pharmacist for determining need tho, and most people that go into pharmacies coughing loudly and asking for it will get the answer - "we dont have any sorry"
in its most common form (tylenol #3) its schedule III.
when its by itself with no other ingredients like tylenol, however, its actually a schedule II. there are commercially available 30mg codeine tabs but they arent commonly used because its too much of a hassle for MDs to write a CII script for every fill (schedule II scripts can have no refills)
another funny one is phencyclidine (PCP)
most people think its a schedule I but it aint.
some vets use it to control seizures in animals and thats a legitimate medical use. schedule II.
ho ho ho blah blah blah
anyways, johnclark is giving you really good advice, but do be mindful that its still possible to become dependant on a drug while taking it per the MDs directions. MDs arent perfect, and some have more loose prescribing practices when it comes to drugs of abuse.
if you are concerned about the amount the MD has you taking and for how long, dont hesitate to get a second opinion.
and no you wont become physically addicted after one dose of oxycodone.