I was taking vicodin 5-550 for a torn meniscus. now i have 5-325 and it is not working. why?

Not sure.: Seems like little difference between the two doses, but it is possible that you might need to increase the dose a bit. The other possibility is that you have irritated your injury a little bit more therefore it requires a bit more med.

Add adjuvant agent: In some patients, the use of an opioid drug alone may cause intolerable side effects or provide inadequate pain relief. To avoid this problem, the use of adjuvant (co-analgesic) nonopioid agents along with an opioid is encouraged to reduce the amount of the single opioid needed. Examples are oral corticosteroids, tricyclic antidepressants, anticonvulsants, and skeletal muscle relaxants.