Sulfasalazine 500 mg is an oral medicine belonging to the category of aminosalicylates and is used for the following indications: 

1. Ulcerative colitis  
2. Rheumatoid arthritis 
3. Juvenile Idiopathic Arthritis (arthritis in children) 
4. Bowel inflammation 
5. Diarrhea 
6. Rectal bleeding 

More Common  

1. Aching of joints  
2. Fever  
3. Headache (continuing)  
4. Increased sensitivity of the skin to sunlight  
5. Skin rash or itching  
6. Vomiting 

Less Common 

1. Back, leg, or stomach pains 
2. Bleeding gums 
3. Bluish color of the fingernails, lips, skin, palms, or nail beds 
4. Chills 
5. Dark urine 
6. Difficulty breathing 
7. Fever 
8. General body swelling 
9. Headache 
10. Loss of appetite 
11. Nausea 
12. Nosebleeds 
13. Pale skin 
14. Sore throat 
15. Trouble breathing 
16. Unusual bleeding or bruising 
17. Unusual tiredness or weakness 
18. Yellowing of the eyes or skin 

Sulfasalazine works by breaking down in the intestine into two parts: 5‑aminosalicylic acid, which stays in the gut and reduces inflammation chemicals, and sulfapyridine, which enters the blood and helps calm the immune system. In ulcerative colitis and Crohn’s disease, it suppresses immune activity in the bowel lining, which results in reducing swelling and bleeding. In rheumatoid and juvenile arthritis, it slows the immune attack on the joints, easing stiffness and preventing damage.

Pregnancy

The safety of sulfasalazine in pregnancy is not established. Inform your doctor if you are pregnant or planning to conceive.

Breastfeeding

Sulfasalazine is not usually recommended during breastfeeding because there is no reliable information on whether it passes into breast milk or how it might affect a nursing infant.

Kidney and Liver Problems

Patients with previous liver and kidney damage are not recommended to take the medicine, as it can cause liver and kidney toxicity while being removed from the body.

Heart Problems

Sulfasalazine is not usually used for heart problems, but if someone already has heart disease doctors are careful with it, because it can sometimes affect the blood vessels and in rare cases make heart issues worse.

The use of drinks that contain alcohol raises your risk of low blood pressure from Sulfasalazine. If you drink alcohol, talk to your doctor. You may need to have your blood pressure monitored while you take this drug.

Avoid taking Sulfasalazine 500 mg with the following medicines, as it may increase or decrease the desired effect, or in worse cases, it could be fatal:

IUPAC (International Union of Pure and Applied Chemistry)/ Chemical name

2‑hydroxy‑5‑[(E)‑2‑{4‑[(pyridin‑2‑yl)sulfamoyl]phenyl}diazen‑1‑yl]benzoic acid 

Daily dose

Take Sulfasalazine exactly as your doctor recommends. The dose may change based on your condition and how well you respond. Do not take more than prescribed without consulting your doctor.

Missed Dose

If you forget to take your medicine, take the medication as soon as you remember. If it’s nearly time for your next dose, skip the missed one and continue with your regular schedule. Always consult the doctor before making any changes to your dosage.

Overdose

It is not recommended to take more than 4000 mg of Sulfasalazine per day, as it may cause severe overdosing effects like extreme drowsiness, confusion, unconsciousness, sweating, double vision, low blood pressure, and slurred speech. Immediately seek medical attention and meet the doctor if necessary.

1. Store the medicine at room temperature 
2. Keep away from sunlight and moisture 
3. Keep out of reach of children 

1. Take Sulfasalazine exactly as prescribed by your doctor, at the same time each day. 
2. Do not stop taking Sulfasalazine without your doctor’s approval, even if you feel better. 
3. If you forget to take Sulfasalazine, take it as soon as you remember. If it’s almost time for your next dose, skip the missed dose. 

Sulfasalazine is a medicine that belongs to the sulfonamide and aminosalicylate group and is used to calm inflammation in the gut and joints by blocking certain chemicals that cause swelling and pain. It is approved for ulcerative colitis, rheumatoid arthritis, bowel inflammation, diarrhea, and rectal bleeding. Common side effects of this medicine are nausea, headache, rash, stomach upset, and orange urine or tears. Taking it with food helps reduce stomach irritation, while alcohol can stress the liver. It should be avoided usually in pregnant women, men planning children, and people with liver, kidney, or blood problems. Overdose occurs by taking more than 2000 mg of sulfasalazine and can be dangerous and may require medical care. In simple terms, sulfasalazine is a slow acting medicine that cools down inflammation but requires hydration, sun protection, and regular blood tests to stay safe.

Who should avoid sulfasalazine tablets? 

People who should avoid sulfasalazine include those with allergies to sulfa drugs or aspirin‑like medicines, rare blood conditions such as porphyria, severe liver or kidney problems, urinary or intestinal blockage, or a genetic condition called G6PD deficiency.

What are the side effects of Sulfasalazine tablets?

Sulfasalazine tablets can cause nausea, headache, rash, stomach upset, and orange‑yellow urine or tears. Rarely, they may lead to liver problems, low blood counts, or allergic reactions that need urgent medical care.

Which class does sulfasalazine belong to?

Sulfasalazine belongs to the drug classes of sulfonamides and amino salicylates, and it is also categorized as a slow‑acting disease‑modifying anti‑rheumatic drug (DMARD).

What is Sulfasalazine’s highest dose?

The highest recommended dose of sulfasalazine in adults is about 4 grams per day, divided into smaller doses. Going above this increases the risk of toxicity and side effects

1. StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan–. Sulfasalazine. [Updated 2024 Dec 12]. Available from. 
2. Mayo Clinic. Sulfasalazine (oral route) [Internet]. Rochester (MN): Mayo Foundation for Medical Education and Research; 2025. Available from. 
3. Drugs.com. Sulfasalazine: Uses, Dosage, Side Effects [Internet]. Drugs.com; 2025. Available from. 
4. National Center for Biotechnology Information (NCBI). PubChem Compound Summary for CID 5359476, Sulfasalazine [Internet]. Bethesda (MD): National Library of Medicine; 2025. Available from.