Sulfasalazine Side Effects
Some side effects of sulfasalazine may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.
For the Consumer
Applies to sulfasalazine: oral delayed release tablet, oral tablet
Get emergency medical help if you have any of these signs of an allergic reaction while taking sulfasalazine: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Stop using sulfasalazine and call your doctor at once if you have any of these serious side effects:
fever, sore throat, or other flu symptoms;
pale skin, easy bruising;
dark urine, jaundice (yellowing of the skin or eyes);
pain or burning when you urinate;
urinating less than usual or not at all;
the appearance of a whole tablet in your stool; or
fever, sore throat, and headache with a severe blistering, peeling, and red skin rash.
Less serious side effects of sulfasalazine may include:
mild nausea, vomiting, diarrhea, upset stomach;
loss of appetite;
headache, ringing in your ears;
dizziness, spinning sensation;
white patches or sores inside your mouth or on your lips;
sleep problems (insomnia); or
mild itching or skin rash.
This is not a complete list of side effects and others may occur. Tell your doctor about any unusual or bothersome side effect.
For Healthcare Professionals
Applies to sulfasalazine: compounding powder, oral delayed release tablet, oral tablet
Gastrointestinal intolerance to sulfasalazine occurred frequently and resulted in drug withdrawal in 17% of treated patients. Hypersensitivity reactions accounted for therapy withdrawal in 13% of sulfasalazine-treated patients. Hypersensitivity adverse effects are generally attributed to the sulfapyridine moiety, which is common and is often the cause of serious complications in patients receiving sulfasalazine.
The use of sulfonamides, including sulfasalazine, is associated with large increases in the risk of Stevens-Johnson syndrome or toxic epidermal necrolysis, although these phenomena are rare as a whole.
Hypersensitivity side effects have included sulfasalazine-induced rash, erythema multiforme (Stevens-Johnson syndrome), exfoliative dermatitis, toxic epidermal necrolysis (Lyell's syndrome) with corneal damage, drug rash with eosinophilia and systemic symptoms (DRESS), anaphylaxis, serum sickness syndrome, pneumonitis (with or without eosinophilia), vasculitis, fibrosing alveolitis, pleuritis, pericarditis (with or without tamponade), allergic myocarditis, polyarteritis nodosa, lupus erythematosus-like syndrome, hepatitis and hepatic necrosis (with or without immune complexes), fulminant hepatitis (sometimes leading to liver transplantation), parapsoriasis varioliformis acuta (Mucha-Haberman syndrome), rhabdomyolysis, photosensitization, arthralgia, periorbital edema, conjunctival and scleral injection, alopecia, and interstitial lung disease.
Gastrointestinal side effects have included anorexia, nausea, vomiting, gastric distress, dyspepsia, stomatitis, abdominal pain, pancreatitis, altered taste, diarrhea (including bloody diarrhea), impaired folic acid absorption, impaired digoxin absorption, hemorrhagic colitis, and neutropenic enterocolitis. Pseudomembranous colitis has been reported in at least one patient, and necrotizing pancreatitis in at least two patients. The use of enteric-coated preparations may decrease gastrointestinal adverse effects.
Hepatitis associated with sulfasalazine often developed two to four weeks after therapy was initiated, although hypersensitivity hepatitis has been reported after longer periods of therapy. Associated rash usually progressed to desquamation. Liver biopsy has shown necrosis and infiltration with moderate number of inflammatory cells. Noncaseating granulomas have also been seen. Hepatitis generally resolved over several weeks after therapy discontinuation, although some patients progressed to fulminant hepatic failure.
Hepatic side effects have included abnormal liver function tests, hepatitis, and hepatic failure. Hepatitis has been reported in patients with sulfasalazine hypersensitivity. Hepatotoxicity, including elevated liver function tests, jaundice, cholestatic jaundice, cirrhosis, and possible hepatocellular damage including liver necrosis and liver failure have been reported during postmarketing experience with the use of products containing or metabolized to mesalamine. Some of these cases were fatal.
Hematologic side effects have included agranulocytosis, leukopenia, thrombocytopenia, hemolytic anemia and cyanosis, Heinz body anemia, aplastic anemia, purpura, hypoprothrombinemia, methemoglobinemia, congenital neutropenia, myelodysplastic syndrome, red cell aplasia, and megaloblastic (macrocytic) anemia.
Agranulocytosis has been reported to generally occur during the first one to three months of therapy. Patients often present with fever and sore throat. A few have also presented with a rash. Bone marrow hypoplasia or aplasia is usually confined to the myeloid series, but may be accompanied by erythroid hypoplasia and marrow plasmacytosis. In one review of 62 cases of sulfasalazine-induced agranulocytosis, 6.5% of patients died. Recovery of granulocytes is generally seen within one to two weeks after drug discontinuation, and leukocyte counts and differential return to normal in one to three weeks. Some cases of agranulocytosis have been treated with colony stimulating factor, which appears to increase the time to recovery.
Patients often presented after several weeks or months of therapy with fever, malaise, shortness of breath, and nonproductive cough. Eosinophilic infiltrates have been seen. Respiratory changes generally resolved over a few weeks, however, fatal reactions involving fibrosing alveolitis have been reported.
Respiratory side effects have included pulmonary infiltrates (frequently accompanied by eosinophilia), fibrosing alveolitis, and bronchiolitis obliterans. Sulfasalazine lung toxicity may mimic Wegener's granulomatosis and false positive c-ANCAs have been found in patients with ulcerative colitis.
Immunoglobulin suppression was slowly reversible and rarely accompanied by clinical findings.
In most cases of sulfasalazine-induced SLE, patients received the drug for greater than one year. Patients most commonly developed arthralgias and pleuritic chest pain. Generally, these patients had a positive ANA, anti-DNA antibody titer, and were slow acetylators of sulfonamides. Symptoms typically resolved over several weeks to several months.
Immunologic side effects have included a 10% rate of immunoglobulin suppression and drug-induced systemic lupus erythematosus (SLE).
Transverse myelitis developed in one patient after receiving sulfasalazine for two years. All symptoms resolved within two months after discontinuing sulfasalazine.
Nervous system side effects have included dizziness, headache, malaise, insomnia, meningitis (including aseptic meningitis), neurotoxicity, seizures, dysphasia, neuropathy (including peripheral neuropathy), acute encephalopathy, monoparesis, transverse myelitis, transient lesions of the posterior spinal column, cauda equina syndrome, Guillain-Barre syndrome, cerebrospinal fluid abnormalities, vertigo, hearing loss, ataxia, hallucinations, tinnitus, and drowsiness.
Renal side effects have included toxic nephrosis with oliguria and anuria, nephritis (including interstitial nephritis), nephrotic syndrome, and hemolytic uremic syndrome. At least one patient developed bilateral renal calculi composed of acetylsulfapyridine, a metabolite of sulfasalazine. Proteinase 3-ANCA positive necrotizing glomerulonephritis has been reported in at least one patient.
Cardiovascular side effects have included tachycardia.
Infertility appears to be reversible upon drug discontinuation.
Genitourinary side effects have included reversible oligospermia, decreased motility, and abnormal sperm penetration sometimes resulting in infertility. Impotence (rare), urinary tract infections, hematuria, crystalluria, proteinuria, and urine discoloration have been reported.
Dermatologic side effects have included rash, pruritus, urticaria, and skin discoloration. Rare cases of lichen planus and at least two cases of toxic epidermal necrolysis have been reported.
Psychiatric side effects have included depression, confusion, and vivid dreams.
Musculoskeletal side effects have included myopathy.
Other side effects have included fever. At least one case of Kawasaki-like syndrome with hepatic function changes has been reported during postmarketing experience with the use of products containing or metabolized to mesalamine.
Ocular side effects have included diplopia and blurred vision.
More sulfasalazine resources
- sulfasalazine Concise Consumer Information (Cerner Multum)
- sulfasalazine Oral, Rectal Advanced Consumer (Micromedex) - Includes Dosage Information
- sulfasalazine MedFacts Consumer Leaflet (Wolters Kluwer)
- Azulfidine Oral, Rectal Advanced Consumer (Micromedex) - Includes Dosage Information
- Azulfidine Prescribing Information (FDA)
- Azulfidine EN-tabs delayed-release tablets MedFacts Consumer Leaflet (Wolters Kluwer)
- Sulfasalazine Prescribing Information (FDA)
- Sulfasalazine Monograph (AHFS DI)
- Sulfasalazine Professional Patient Advice (Wolters Kluwer)
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