i don't care if this thread is over 5.5 yrs old.
i found a wonderful resource for the op.
Medscape: Free CME, Medical News, Full-text Journal Articles & More
search "promethazine inj" under drug reference.
go to:
detailed monograph,
click on 'cautions'.
there's a huge blurb under "local reactions".
"Severe chemical irritation and damage to tissues (e.g., burning, pain, erythema, swelling, severe spasm of distal vessels, thrombophlebitis, venous thrombosis, phlebitis, abscesses, tissue necrosis, gangrene) may occur with administration of promethazine injection, regardless of the route of administration...."
fyi, incase someone else finds this info useful?