Can you mix vicodin 750 with morphine 15mg?

I can, yes, thanks for asking. There would no advantage over 30 mg of OxyContin. 30 Mgs. Of Vicodin would not be a good idea because you would also be getting traditionally 3000 Mgs. Of acetaminophen. If you wanted a long acting opiate/opioid with for breakthrough you would be better of taking Ocycontin with oxycodone ir. Since you need a precipitous to obtain either of these

I would recommend you ask your prescribing doctor how to take your meds. If your doctor is a moron ask the pharmacist who dispenses them.