It could be the sulfasalazine:
http://www.nlm.nih.gov/medlineplus/druginfo/medmaster/a682204.html
or
the famotidine:
http://www.nlm.nih.gov/medlineplus/druginfo/medmaster/a687011.html
If you can't get a hold of the doctor...maybe stop at least the famotidine and see if you improve.
The "game's a foot Watson!".
q