Phenergan is a brand of Promethazine.
I keep this med on hand in suppository form for vomiting associated with viral GI infection (aka stomach bug)
I use it only if vomiting is persistent and I can't keep down anything by mouth (including a popsicle)
I've just found that once the stomach is empty and one is "dry heeving", it makes sense to stop those smooth muscle spasms and wait comfortably for the virus to run its course. This med causes sedation, so an added benefit is a few restful hours of sleep after which I can usually tolerate clear liquids by mouth.
Luckily, my PCP agrees with me about this and readily gives me the script to keep on hand and in the frig for "emergencies". She probably likes that I will not be calling her answering service in the middle of the night or on weekends ! :)
I'm not sure why it says that MEPERIDINE is a brand of promethazine.
AFAIK, Meperidine is the generic for Demerol, which is a sched II narcotic (although there is a combination drug which contains promethazine to curb the potential side effect of nausea)