sulfasalazine
Brand names: Azulfidine
Sulfasalazine is a drug that reduces inflammation in the body. It is used to treat ulcerative colitis.
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.
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.
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.
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.
Storage
Store at room temperature between 59°F and 86°F.
Side Effects (from patient reports)
Based on 147,268 FDA adverse event reports.
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
Death-Related Reports
6,629
Hospitalization Reports
20,613
Top Indication
Rheumatoid Arthritis
Gender Distribution
Age Distribution
Most Reported Adverse Reactions (FAERS)
| # | Reaction | Reports |
|---|---|---|
| 1 | DRUG INEFFECTIVE | 29,013 |
| 2 | RHEUMATOID ARTHRITIS | 19,190 |
| 3 | PAIN | 15,658 |
| 4 | DRUG INTOLERANCE | 13,521 |
| 5 | ARTHRALGIA | 13,161 |
| 6 | FATIGUE | 13,017 |
| 7 | JOINT SWELLING | 12,481 |
| 8 | OFF LABEL USE | 10,749 |
| 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 |
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, ifos...
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.
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?
Related Medications in Disease-Modifying Antirheumatic Drug (DMARD)
Other drugs grouped near sulfasalazine — same-class peers and common alternatives.
abatacept
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acetaminophen/hydrocodone
Vicodin, Norco
This medicine contains acetaminophen and hydrocodone.
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acetaminophen/oxycodone
Percocet
Percocet is a strong pain medicine.
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Humira
Idacio is a medicine that blocks a protein called TNF.
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Medication Guides
Understanding Drug Interactions
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FDA requirements, cost savings, and when the difference matters
Narrow Therapeutic Index Drugs
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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 147,268 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.
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