Is hydrocodone and flexoril safe to take with phentermine?

Ok 2 use but caution: Hydrocodone is a narcotic which can cause drowsiness, so is flexeril (cyclobenzaprine hcl). Thus, using these two can compound this effect and so caution is advised. Neither of these has any significant interaction with phentermine. Like all medicine, use the smallest effective dosage for the shortest duration possible. Consult doc. Good luck.

Why?: Why are you taking all these meds? You need to evaluate your situation and determine if you need them and whether you're abusing them. Try to wean yourself off of them and live a healthier life. Those are some very potent meds with significant potential side effects.