Prescription medication · Disease-Modifying Antirheumatic Drug (DMARD)
sulfasalazine
Also sold as Azulfidine. Sulfasalazine treats ulcerative colitis, a condition that causes inflammation and sores in the lining of the large intestine.
Data updated 2026-05-15
- 76,270
- FDA reportsOften reported
- 7
- InteractionsFew interactions
- $0.18
- Generic price (NADAC)
What the data shows
sulfasalazine (Azulfidine) is a prescription Disease-Modifying Antirheumatic Drug (DMARD), more reported than most tracked drugs (76,270 FDA reports), with 7 documented drug interactions.
Reporting volume reflects how widely a drug is used and studied, not how dangerous it is, a FAERS report documents a temporal association, never proof of cause.
sulfasalazine (Azulfidine) is a prescription Disease-Modifying Antirheumatic Drug (DMARD). Sulfasalazine treats ulcerative colitis, a condition that causes inflammation and sores in the lining of the large intestine.
Sulfasalazine is a drug that reduces inflammation in the body. It is used to treat ulcerative colitis.
Verify with FDA → · CMS NADAC pricing →
Drug Pricing (NADAC)
Generic Price
$0.18/unit
Generic Available
Yes (5 manufacturers)
Pricing data from NADAC (CMS), effective December 18, 2024. Compare all drug costs →
What it does
Sulfasalazine treats ulcerative colitis, a condition that causes inflammation and sores in the lining of the large intestine.
Common side effects
Loss of appetite, Headache, Nausea
Key warnings
You should not take this medicine if you have a blockage in your intestines or urinary tract.
The sections below are summarized in plain English from sulfasalazine's FDA-approved prescribing information. They describe what the official label says, and are not personal medical advice.
How It Works
Sulfasalazine is an anti-inflammatory drug. It works by reducing inflammation in the colon. The exact way it does this is not fully known.
How to Take It
Take Sulfasalazine as your doctor tells you. The usual starting dose for adults is 3 to 4 grams per day, divided into equal doses taken every 8 hours. Some people start with a lower dose, like 1 to 2 grams per day, to avoid stomach problems. Your doctor may adjust your dose based on how well the medicine works for you.
This is a plain-language summary of sulfasalazine's FDA labeling, not individualized dosing advice. Ask a pharmacist or prescriber before changing how you take this medication.
Pregnancy & Breastfeeding
Tell your doctor if you are pregnant or plan to become pregnant. It is not known if Sulfasalazine will harm your unborn baby. Talk to your doctor about the risks and benefits of taking this medicine while breastfeeding.
This is a plain-language summary of sulfasalazine's FDA labeling, not individualized advice. Ask a pharmacist or prescriber about pregnancy or breastfeeding on this medication.
Missed Dose
If you miss a dose, take it as soon as you remember. If it is close to your next dose, skip the missed dose and continue with your regular schedule.
This is a plain-language summary of sulfasalazine's FDA labeling, not individualized advice. Ask a pharmacist or prescriber what to do about your specific missed dose.
Storage
Store at room temperature between 59°F and 86°F.
Side Effects (from patient reports)
Based on 76,270 FDA adverse event reports.
Most-reported reactions
Adverse reactions in FAERS for sulfasalazine, by number of reports
- Rheumatoid arthritis
Rheumatoid arthritis
19,190 reports
- Pain
Pain
15,658 reports
- Joint pain
Joint pain
13,161 reports
- Tiredness
Tiredness
13,017 reports
- Swollen joint
Swollen joint
12,481 reports
- Skin rash
Skin rash
10,677 reports
- Stomach discomfort
Stomach discomfort
9,801 reports
- Given a medicine that should not have been given
Given a medicine that should not have been given
9,454 reports
- Condition got worse
Condition got worse
9,375 reports
- Hair loss
Hair loss
9,277 reports
What this shows Bars show how often each reaction was reported, not how likely it is to happen, a report records a temporal association, never proof that the drug caused it.
Reports over time
Adverse-event reports filed for sulfasalazine each year to the FDA Adverse Event Reporting System (FAERS).
Year-to-year volume tracks usage, prescribing, and scrutiny, not a change in per-patient risk. Source: FDA FAERS.
Where sulfasalazine sits
sulfasalazine has more FDA adverse-event reports than 82% of the drugs FAERS tracks. A high position reflects how widely a drug is used and watched, not how dangerous it is.
Percentile across all drugs PlainMeds tracks by FAERS report volume. The dot is sulfasalazine; the line is the median (50th percentile).
FDA Adverse Event Report Analysis
Detailed analysis of 76,270 reports from the FDA Adverse Event Reporting System (FAERS). Reports span 2003–2025.
Total Reports
76,270
Reports Mentioning Death
6,629
8.7% of reports — not proof of cause
Hospitalization Reports
20,613
Top Indication
Rheumatoid Arthritis
Gender Distribution
Age Distribution
Most Reported Adverse Reactions (FAERS)
| # | Reaction | Reports |
|---|---|---|
| 2 | RHEUMATOID ARTHRITIS | 19,190 |
| 3 | PAIN | 15,658 |
| 5 | ARTHRALGIA | 13,161 |
| 6 | FATIGUE | 13,017 |
| 7 | JOINT SWELLING | 12,481 |
| 9 | RASH | 10,678 |
| 10 | ABDOMINAL DISCOMFORT | 9,801 |
| 11 | CONTRAINDICATED PRODUCT ADMINISTERED | 9,454 |
| 12 | CONDITION AGGRAVATED | 9,374 |
| 13 | ALOPECIA | 9,277 |
| 14 | ARTHROPATHY | 9,001 |
| 15 | SYNOVITIS | 8,965 |
| 16 | TREATMENT FAILURE | 8,687 |
| 17 | SYSTEMIC LUPUS ERYTHEMATOSUS | 8,588 |
| 18 | SWELLING | 8,508 |
Reactions in Death Reports
Reactions in Hospitalization Reports
Source: FDA FAERS (Adverse Event Reporting System) FDA FAERS (Adverse Event Reporting System) Reports are voluntary and do not establish causation
Serious Warnings
You should not take this medicine if you have a blockage in your intestines or urinary tract. You should not take this medicine if you have porphyria, as it could cause an attack. You should not take this medicine if you are allergic to sulfasalazine, its ingredients, sulfonamides, or salicylates.
Known Drug Interactions
Drugs That May Cause Methemoglobinemia When Used with LIDODERM Patients who are administered local anesthetics are at increased risk of developing methemoglobinemia when concurrently exposed to the following drugs, which could include other local anesthetics: Examples of Drugs Associated with Methemoglobinemia : Class Examples Nitrates/Nitrites nitric oxide, nitroglycerin, nitroprusside, nitrous oxide Local anesthetics articaine, benzocaine, bupivacaine, lidocaine, mepivacaine, prilocaine, procaine, ropivacaine, tetracaine Antineoplastic agents cyclophosphamide, flutamide, hydroxyurea,...
Mechanism: Both drugs can cause a rare blood problem that prevents oxygen from reaching your body's tissues. Using them together makes this dangerous side effect more likely to happen.
What to do: Your doctor should monitor you closely for signs like blue skin or shortness of breath. Seek medical help immediately if you feel unusually tired or dizzy.
Coadministration of VOSEVI with BCRP substrates (e.g., methotrexate, mitoxantrone, imatinib, irinotecan, lapatinib, rosuvastatin, sulfasalazine, topotecan) is not recommended [see Clinical Pharmacology (12.3) ].
Mechanism: This medicine interferes with a protein that transports sulfasalazine, which could cause the levels of sulfasalazine in your body to rise.
What to do: The manufacturer does not recommend taking these two medications at the same time.
John's Wort, sucralfate, sulfasalazine Measure serum digoxin concentrations before initiating concomitant drugs.
Mechanism: Sulfasalazine can decrease the amount of digoxin in your blood, making the heart medicine less effective.
What to do: Your doctor should check your digoxin levels before you begin taking this combination.
7.5 Effects of Other Drugs on Folates Several drugs have been reported to reduce folate concentrations by inhibition of the dihydrofolate reductase enzyme (e.g., methotrexate and sulfasalazine) or by reducing folate absorption (e.g., cholestyramine), or via unknown mechanisms (e.g., antiepileptics such as carbamazepine, phenytoin, phenobarbital, primidone and valproic acid).
Mechanism: Sulfasalazine can lower the levels of folate in your body by blocking a specific enzyme that helps process it.
What to do: Your doctor may need to monitor your folate levels or adjust your supplements while taking these medications together.
7.4 Sulfasalazine Patients in a clinical study who were on established therapy with sulfasalazine, to which Enbrel was added, were noted to develop a mild decrease in mean neutrophil counts in comparison to groups treated with either Enbrel or sulfasalazine alone.
Mechanism: Taking these two medicines together can lower the number of white blood cells that help your body fight infections.
What to do: Your doctor should monitor your blood cell counts regularly while you are using both medications.
This is a plain-language summary of interactions documented in FDA labeling, not individualized advice. Ask a pharmacist or prescriber before combining medications.
Common Questions
Can I take this with food?
What if I have stomach upset?
How long will I need to take this medicine?
Can this medicine affect my ability to have children?
What should I do if I think I'm having an allergic reaction?
Can I take other medicines with Sulfasalazine?
Will this medicine cure my ulcerative colitis?
How long does it take for this medicine to work?
Can this medicine cause my urine to change color?
Is it safe to get vaccines while taking Sulfasalazine?
What are the common side effects of sulfasalazine?
Does sulfasalazine interact with other medications?
What drug class is sulfasalazine?
Is sulfasalazine safe during pregnancy?
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Medication Guides
Understanding Drug Interactions
How CYP450 enzymes, inhibitors, and inducers affect your medications
Generic vs Brand Name Drugs
FDA requirements, cost savings, and when the difference matters
Narrow Therapeutic Index Drugs
Why some drugs demand precise dosing and monitoring
Common Drug Interactions
Dangerous medication combinations and how to protect yourself
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What the FDA Data Shows for sulfasalazine
The FDA label for sulfasalazine (sold under brand names such as Azulfidine) classifies it as a prescription-only medication in the Disease-Modifying Antirheumatic Drug (DMARD) class. Sulfasalazine treats ulcerative colitis, a condition that causes inflammation and sores in the lining of the large intestine. Official labeling lists 6 commonly reported side effects, including Loss of appetite, Headache, Nausea.
Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 76,270 voluntary reports. The database also lists 7 documented drug interactions derived from FDA labeling, with the top-flagged interaction rated moderate severity. NADAC pricing from CMS shows a generic unit cost of $0.18.
Report counts do not establish causation, a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history, and patent information further shape supply and switching decisions. This page summarizes public FDA data for educational purposes only and is not a substitute for professional medical advice, always consult a licensed healthcare provider before starting, stopping, or changing any medication.
Data Sources
Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS). Pricing: CMS National Average Drug Acquisition Cost (NADAC).
FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. Always consult a healthcare professional before making medication decisions.
Last updated: December 12, 2022
Read our methodology - how this data is sourced, computed, and verified.
Data currency: FDA FAERS adverse-event reports through 2025, CMS NADAC acquisition-cost pricing effective December 2024, compiled and last refreshed May 2026. See our methodology for per-source dates and refresh cadence. Spot a figure that looks wrong? Report a correction.
All federal data sources used on this page
- FDA Orange Book - approved drug products with therapeutic equivalence. accessdata.fda.gov/cder/ob
- FDA DailyMed - NIH-hosted drug labeling for FDA-approved meds. dailymed.nlm.nih.gov
- FDA Adverse Event Reporting System (FAERS) - post-marketing safety surveillance. fda.gov/drugs/faers
- NLM RxNorm - standardized clinical drug nomenclature. nlm.nih.gov/research/umls/rxnorm
- CMS Medicare Part B Drug Average Sales Price Files - federal drug pricing data. cms.gov/medicare/part-b-drugs/asp
- FDA Drug Shortages Database - current and resolved drug shortage tracking. accessdata.fda.gov/drugshortages