Acetaminophen / oxycodone
"Generic drugs can be produced by several different pharmaceutical manufacturers and more than likely, if you look up the ingredients from each one, you will find that they all use different binders/fillers and such. Because of this, your experience with these drugs may include nausea, nervousness, upset stomach, etc. so my suggestion is that if you take a generic drug and are having problems or it isn't "doing what it's supposed to do" you may want to ask your pharmacist to change suppliers for you. In regard to generic Percocet, I had this problem. Yes, they did relieve my pain but some did it better than others and several  made me 'nervous' and gave me an upset stomach. Most pharmacist's are aware of this difference."