Hello, blktears,

This is a question that needs to be answered by his doctor, but I can give you some information. There are factors to be considered in addition to possible interactions between these medications -- any health issues/conditions he may have, and ALL other medications he's taking including prescription medications, over-the-counter medications, dietary supplements, etc.

If his doctor won't discuss his treatment, then it's time for a new doctor. Keep in mind, however, that if he's legally an adult and hasn't been judged unable to make his own medical decsions, his doctor doesn't have to talk to or listen to anyone but your brother.

Here are the interactions I found listed for his medications:

1. OxyContin <-> Percocet
caution advised, consider dose reduction: combo may incr. risk of CNS and respiratory depression, profound sedation, hypotension, other adverse effects due to additive effects.
2. OxyContin <-> Vistaril
caution advised, consider opioid dose reduction: combination may increase risk of severe constipation/paralytic ileus, CNS depression, psychomotor impairment, other adverse effects due to additive effects
3. OxyContin <-> Xanax
caution advised, especially with IV benzodiazepines and IV opioids, consider dose reduction: combination may result in vasodilation, severe hypotension, CNS and respiratory depression, psychomotor impairment due to additive effects
4. Percocet 10/325 <-> Vistaril
caution advised: combination may increasse risk of CNS depression, psychomotor impairment, other adverse effects due to additive/synergistic effects
5. Percocet 10/325 <-> Xanax
caution advised: combination may increase risk of CNS depression, psychomotor impairment due to additive effects
6. Vistaril <-> Xanax
caution advised: combination may increase risk of CNS depression due to additive effects

I hope this helps,

Teri