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Sulfasalazine Side Effects
Loss of appetite, nausea or vomiting, and headache are some of the most commonly reported sulfasalazine side effects. Less common side effects include insomnia, drowsiness, and urine discoloration. Side effects of sulfasalazine that are more serious and should be reported to a healthcare provider right away include hallucinations, worsening of ulcerative colitis symptoms, and easy bruising or unusual paleness.
As with any medicine, side effects are possible with sulfasalazine (Azulfidine®); however, not everyone who takes the medication will experience side effects. In fact, most people tolerate it quite well. If side effects do occur, in most cases, they are minor and either require no treatment or can easily be treated by you or your healthcare provider.
(This article covers many, but not all, of the possible side effects with sulfasalazine. Your healthcare provider can discuss a more complete list of sulfasalazine side effects with you. For side effects of the delayed-release tablets, see Azulfidine EN-tabs Side Effects.)
Sulfasalazine has been studied thoroughly in clinical trials, in which a group of people taking the drug have side effects documented and compared to another group not taking the medicine. This way, it is possible to see what side effects occur, how often they appear, and how they compare to the group not taking the medicine.
In these studies, the most common side effects of sulfasalazine included:
- Loss of appetite
- Headache
- Nausea or vomiting
- Reversible low sperm count in men.
Written by/reviewed by: Kristi Monson, PharmD; Arthur Schoenstadt, MD
Last reviewed by: Kristi Monson, PharmD