Hi!
When I first started taking sulfasalazine I kept getting these sudden chills more or less on a daily basis for months.
I also lost my appetite and lost weight which probably also added to getting chills as I've noticed that when I can't eat very much I tend to feel chilly more easily.
After about half a year the chills stopped, and I don't take sulfasalazine anymore. Now I only get the chills very rarely or if I've caught a flu.
I'm heading to Lapland, to the Arctic Circle for the winter though and it gets really freezing up there so I'm bound to get the chills every once in a while