I've seen the problem with phlebitis when using Phenergan IV. I've also had (and been witness to) events when phenergan IV resulted in over-sedation of a patient... once when administering only 12.5 mg. In this case, we ended up giving narcan to reverse the morphine the patient had also received earlier. Of course, this had it's own ill effects, most notably irritability and severe pain. Even then, the patient was sedated for quite some time.
I find that patients who receive Zofran pre-op have far less incidence of nausea post-operatively. I know I try to avoid giving phenergan whenever possible.
Peace
Nursing News