RxDecoder My Rx
‹ All drugs

sulfasalazine

Sold as Azulfidine. Class: Aminosalicylic acid and similar agents. First FDA approval 06/20/1950: 76 years on the US market.

This grade answers one narrow question: how strong is the public evidence and safety record behind this drug, and how clean is its money trail and court record? It is not a verdict on whether the drug is right for you.

B

Score breakdown (84/100)

Safety ×35%
B
Evidence ×25%
D
Regulatory ×15%
A
Money & lawsuits ×15%
A
Options ×10%
A

Safety: 85

Evidence: 59

Regulatory history: 96

Money & lawsuits: 100

Options: 100

Independent reviews and post-approval warnings

WHO Essential Medicine

Listed on the WHO Model List of Essential Medicines: a global expert panel judged it among the medicines a health system should always have, on evidence of value, not marketing.

What the FDA label says

Approved uses

INDICATIONS AND USAGE Sulfasalazine delayed release tablets are indicated: a) in the treatment of mild to moderate ulcerative colitis, and as adjunctive therapy in severe ulcerative colitis; b) for the prolongation of the remission period between acute attacks of ulcerative colitis; c) in the treatment of patients with rheumatoid arthritis who have responded inadequately to salicylates or other nonsteroidal anti-inflammatory drugs (e.g., an insufficient therapeutic response to, or intolerance of, an adequate trial of full doses of one or more nonsteroidal anti-inflammatory drugs); and d) in the treatment of pediatric patients with polyarticular-course 1 juvenile rheumatoid arthritis who have responded inadequately to salicylates or other nonsteroidal anti-inflammatory drugs. Sulfasalazine delayed release tablets are particularly indicated in patients with ulcerative colitis who cannot take uncoated sulfasalazine tablets because of gastrointestinal intolerance, and in whom there is evidence that this intolerance is not primarily the result of high blood levels of sulfapyridine and its metabolites, e.g., patients experiencing nausea and vomiting with the first few doses of the drug, ...

Contraindications

CONTRAINDICATIONS Sulfasalazine delayed release tablets are contraindicated in: Hypersensitivity to sulfasalazine, its metabolites, sulfonamides or salicylates, Patients with intestinal or urinary obstruction, Patients with porphyria, as the sulfonamides have been reported to precipitate an acute attack.

Warnings and precautions

WARNINGS Hepatic, Renal, and Hematologic Toxicity or Other Conditions Only after critical appraisal should sulfasalazine delayed release tablets be given to patients with hepatic or renal damage or blood dyscrasias. Deaths associated with the administration of sulfasalazine have been reported from hypersensitivity reactions, agranulocytosis, aplastic anemia, other blood dyscrasias, renal and liver damage, irreversible neuromuscular and central nervous system changes, and fibrosing alveolitis. The presence of clinical signs such as sore throat, fever, pallor, purpura, or jaundice may be indications of serious blood disorders or hepatotoxicity. Complete blood counts, as well as urinalysis with careful microscopic examination, should be done frequently in patients receiving sulfasalazine delayed release tablets (see PRECAUTIONS, Laboratory Tests ). Discontinue treatment with sulfasalazine while awaiting the results of blood tests. Discontinue sulfasalazine delayed release tablets if renal function deteriorates while on therapy. Oligospermia and Infertility Oligospermia and infertility have been observed in men treated with sulfasalazine; however, withdrawal of the drug appears to reve...

Adverse reactions (label)

ADVERSE REACTIONS The most common adverse reactions associated with sulfasalazine in ulcerative colitis are anorexia, headache, nausea, vomiting, gastric distress, and apparently reversible oligospermia. These occur in about one-third of the patients. Less frequent adverse reactions are pruritus, urticaria, rash, fever, Heinz body anemia, hemolytic anemia, and cyanosis, which may occur at a frequency of 1 in 30 patients or less. Experience suggests that with a daily dose of 4 g or more, or total serum sulfapyridine levels above 50 µg/mL, the incidence of adverse reactions tends to increase. Similar adverse reactions are associated with sulfasalazine use in adult rheumatoid arthritis, although there was a greater incidence of some reactions. In rheumatoid arthritis studies, the following common adverse reactions were noted: nausea (19%), dyspepsia (13%), rash (13%), headache (9%), abdominal pain (8%), vomiting (8%), fever (5%), dizziness (4%), stomatitis (4%), pruritis (4%), abnormal liver function tests (4%), leukopenia (3%), and thrombocytopenia (1%). One report 7 showed a 10% rate of immunoglobulin suppression, which was slowly reversible and rarely accompanied by clinical findin...

Source: FDA SPL label for Sulfasalazine (Mylan Pharmaceuticals Inc.), effective 20260825. Full label on DailyMed.

Side-effect reports sent to the FDA

These are counts of reports people filed, not rates of harm. Anyone can file one, and nobody checks whether the drug was the cause. Millions of doses are taken for every report sent, so the useful part is how this drug compares with the average across all drugs.

73,709reports that mention this drug
73,646of those blame this drug, not another one the person was taking
86%of reports describe a serious outcome, such as a hospital stay (average for all drugs: 57%)
9.4%of reports include a death, from any cause (average for all drugs: 9.1%)

Problems reported most often

Drug Ineffective · 29,492Rheumatoid Arthritis · 19,455Pain · 15,918Drug Intolerance · 13,870Arthralgia · 13,280Fatigue · 13,217Joint Swelling · 12,737Off Label Use · 11,356Rash · 10,857Abdominal Discomfort · 10,099Contraindicated Product Administered · 9,718Condition Aggravated · 9,618Alopecia · 9,477Synovitis · 9,285Arthropathy · 9,257

Reports per year

20192020202120222023202420252026
8,09811,9867,6087,3035,2415,8484,6601,469

20,512 reports blaming this drug for every million Medicare prescriptions filled, which is 7.4× the typical drug on this site. (11,960 reports in 2024–2026, against 583,061 Medicare fills in one year. This is the one number here that accounts for how many people take the drug.)

Source: the FDA's Adverse Event Reporting System (FAERS). Reports are voluntary and unverified. Drugs that are prescribed a lot, in the news, or in lawsuits attract more reports, so the percentages are compared with the whole database to correct for that partly, not fully.

Recalls and regulatory record

0recall actions on file
4 / 10brand / generic applications
4label changes since 2021
NoREMS program

Evidence base

95randomized trials (PubMed)
20systematic reviews
123registered trials
54%of completed trials posted results
7%terminated or withdrawn
37%industry-funded

Independent Cochrane reviews

Counts measure how much evidence exists and how transparent it is, not how big the benefit is. For that, ask your prescriber: if 100 people like me took this, how many would get better because of it, and how many would be harmed? (Doctors call these the "number needed to treat" and "number needed to harm.") It differs by condition and is the number drug ads leave out. Sources: PubMed, ClinicalTrials.gov.

Money and lawsuits

In 2024, drug companies reported $0 in payments to US physicians and hospitals tied to this drug across 0 transactions.

No pending federal MDL names this drug or its brands.

Not named in any federal pharmaceutical settlement of $100M or more on record.

Sources: CMS Open Payments (Sunshine Act); Judicial Panel on Multidistrict Litigation pending docket list; DOJ settlements as tabulated on Wikipedia with links to the primary record. State-court and individual suits are not included.

Who takes it and what it costs

149,055Medicare Part D patients (2024)
583,061prescriptions filled
$32average cost per fill
$19Mtotal Medicare spend
ProductFills$/fill
Sulfasalazine451,008$28
Sulfasalazine Dr131,521$45
Azulfidine532$437

Same-class alternatives

balsalazideolsalazine

Same ATC pharmacological class, graded ones first, best grade at the top. Being in the same class does not make them interchangeable for your condition; it makes them worth asking about.

Questions to ask your prescriber

  1. The most-reported problems in FDA's adverse event data are rheumatoid arthritis, pain, drug intolerance. How would we recognize and handle those?
  2. Why this one over balsalazide, mesalamine, olsalazine? What would make you pick one of those instead?
  3. What result are we expecting, by when, and what is the plan if it does not happen?
  4. If 100 people like me took this drug, how many would actually get better because of it, and how many would be harmed by it? (Doctors call these the number needed to treat and the number needed to harm.)