Vicoden is a brand name for oxycodone with acetaminophen. Oxycontin is a brand name for controlled release
oxycodone. Same opioid. Sorry to be the bearer of bad
news...
Not sure about the white packets though. You can order testing kits online - just look up 'field drug tests'. But you might as well just ask him what it is instead of going through all that. If he won't be honest about it with you, there's not much you can do in any case.