My dr gave me norco 10/325 & phenergan (promethazine) 25 mg for knee injury. & gave me flexeril 5 mg. can i take all of them together or space them out by 2 hours.

All are sedating: This could be potently sedating cocktail for someone who is not already used-to (tolerant to) these medications. If instructions are unclear I would ask the prescribing doc how he or she intends you to take these. Usually Norco is taken preferentially as-needed for pain. Phenergan (promethazine) would be taken if you get nausea or itching from the Norco. Flexeril, however has a less clear role in knee injury