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Sulfasalazine
Last reviewed: 03.07.2025
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Sulfasalazine is an anti-inflammatory drug widely used in the long-term treatment of chronic inflammatory bowel disease. Sulfasalazine is structurally composed of a sulfonamide (sulfapyridine) and a 5-aminosalacyclic acid (5-ASA) linked by an azo bond. Sulfasalazine is a rare but well-known cause of idiosyncratic liver disease.
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Indications Sulfasalazine
Currently, indications are shown for the treatment of active ulcerative colitis and prevention of relapses of the disease in both adults and children. Sulfasalazine is also used in rheumatoid arthritis in adolescents and adults.
Release form
Sulfasalazine is available as generic 500 mg tablets and under the trade name azulfidine. Extended release forms are also available.
Pharmacodynamics
Sulfasalazine is a modified sulfonamide consisting of sulfapyridine covalently linked to 5-aminosalacyclic acid (5-ASA). Sulfasalazine is poorly absorbed, but its azo bond is cleaved by bacteria in the intestinal lumen, releasing absorbable sulfapyridine and 5-ASA, which reaches high levels and acts locally to reduce inflammation. Sulfasalazine was approved for clinical use in the United States in 1950 and remains widely used today.
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Pharmacokinetics
The bioavailability of the drug when used in tablet form is 5-10%. Its maximum concentration in blood plasma is achieved within 3-6 hours after administration. The degree of protein binding is high and amounts to 99%.
As for the tendency to cumulation, it is moderate. The concentration of the active component in the blood serum 24 hours after taking is insignificant. A similar situation occurs with urine.
Sulfasalazine is rapidly absorbed and partially metabolized by acetylation/hydroxylation in the liver. Metabolites are completely excreted in the urine. Non-acetylated sulfapyridine only partially binds to plasma proteins. Its maximum concentration is reached within 12 hours after administration. Equilibrium is reached after 5 days. After discontinuation of the drug, its concentration in the blood plasma decreases significantly within 3 days.
Patients with slow acetylation are at risk of developing side effects due to high levels of the main component in the blood plasma. The drug is absorbed by about 20%. It is excreted as pharmacologically inactive acetyl-5-aminosalicylic acid in the urine. Most of the Sulfasalazine remains in the large intestine.
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Dosing and administration
The usual adult dose is initially 3 to 4 grams per day, with a maintenance dose of 2 grams per day (4 doses).
For inflammatory bowel disease, the usual dose is 2 to 4 tablets or 20 to 40 ml of liquid 4 times a day.
For rheumatoid arthritis, when you start treatment, you will usually take one 500 mg tablet per day. This amount will be increased by 1 tablet per day each week until you reach a dose of 1 tablet 4 times per day or 2 tablets 3 times per day, depending on how you respond.
Children's doses are often lower. Your doctor will use your child's weight to calculate the correct dose for him or her. [ 4 ], [ 5 ]
Use Sulfasalazine during pregnancy
Women who want to become pregnant can continue to take sulfasalazine during pregnancy and while breastfeeding. Sulfasalazine does not increase the risk of any pregnancy complications or birth defects. Pregnant women taking sulfasalazine should increase their folic acid intake to 2 mg per day. If you have inflammatory bowel disease, you should talk to your doctor before trying to get pregnant, as they will want to review all your medications.
Contraindications
Before taking sulfasalazine, tell your doctor or pharmacist if you are allergic to it; or to sulfa drugs; or to aspirin and related drugs (salicylates, NSAIDs such as ibuprofen); or to mesalamine; or if you have other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.
Before using this medication, tell your doctor or pharmacist your medical history, especially of: intestinal blockage, urinary blockage, kidney disease, liver disease, blood disorders (eg, aplastic anemia, porphyria), a certain genetic disorder (G6PD deficiency), asthma, severe allergies, current/recent/recurring infections.
This drug may make you dizzy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Limit your drinking. Talk to your doctor if you use marijuana (cannabis).
This medicine may make you more sensitive to the sun. Limit your time in the sun. Avoid tanning beds and sunlamps. Use sunscreen and wear protective clothing when outdoors. Get medical help right away if you get sunburned or have blistering/redness on your skin.
This medicine is similar to aspirin. Children and teenagers younger than 18 years old should not take aspirin or aspirin-related medicines (such as salicylates) if they have chickenpox, the flu, or any undiagnosed illness, or if they have just received a live virus vaccine (such as the varicella vaccine), without first talking to a doctor about Reye's syndrome, a rare but serious illness.
Side effects Sulfasalazine
Side effects are much more common with sulfasalazine. 5-aminosalicylates are generally very well tolerated. Many mild side effects can be avoided by using lower doses of these drugs; serious side effects are uncommon or rare and usually resolve after stopping the medication. In most cases, the potential benefits of these drugs outweigh the potential risks. However, it is important to be aware of possible side effects before starting treatment.
Common side effects include anorexia, headache, nausea, gastrointestinal upset, fever, arthralgia, and rash.
Rare and potentially serious side effects of sulfasalazine (affecting less than 1 percent of people taking the drug) include inflammation of the liver (hepatitis), inflammation of the lungs (pneumonitis), a serious skin reaction called Stevens-Johnson syndrome, and the destruction of red blood cells (hemolysis). Kidney inflammation may also occur. Routine blood tests to monitor kidney function are usually done six weeks and six months after you start taking sulfasalazine, and then annually.
Rarely, a decrease in the number of infection-fighting white blood cells is seen. In some cases, the bone marrow stops producing a certain type of white blood cell altogether, a condition called agranulocytosis. Agranulocytosis usually occurs within two months of starting sulfasalazine and is usually accompanied by fever and rash. In most people, agranulocytosis goes away within one to two weeks of stopping the medication. Everyone taking sulfasalazine is advised to have blood tests. These should be done every one to two weeks for the first six weeks, monthly for three months, and then usually every three months.
Sulfasalazine and sulfonamide allergies
People who are allergic to sulfa drugs may have a cross-reaction to sulfasalazine and therefore should not take it. If sulfasalazine causes mild allergic symptoms but controls symptoms very effectively, desensitization, a method of reducing or eliminating the allergic reaction, may be tried. Desensitization involves starting with a very small dose of sulfasalazine and gradually increasing it over time. This strategy is not usually used for people with inflammatory bowel disease because other treatments are available.
Hepatotoxicity
Sulfasalazine, like other sulfonamides, causes a characteristic idiosyncratic liver injury that has features of drug allergy or hypersensitivity. The typical onset is sudden development of fever and rash, followed by jaundice within days to weeks of drug initiation. Eosinophilia or atypical lymphocytosis are also common. The pattern of injury is usually mixed but may be cholestatic or hepatocellular and may be complex and prolonged. Sulfasalazine has been associated with cases of acute liver failure, particularly with the hepatocellular pattern of injury. However, most cases resolve rapidly after discontinuation of the medication, usually within 2–4 weeks unless cholestasis is severe. Because sulfasalazine is given chronically, rare cases of late-onset drug-induced liver disease have been reported, but the features and pattern of injury are different and the role of other drugs and possibly 5-ASA in these late-onset cases has not yet been defined. resolved. Chronic therapy may also be associated with mild and transient ALT elevations, either alone or as part of a general hypersensitivity reaction; these elevations may be accompanied by liver granulomas.
How to manage sulfasalazine side effects?
- What to do about: Upset stomach and heartburn - taking sulfasalazine a few minutes before or after meals may help. If you need something to ease discomfort, try taking an antacid.
- feeling unwell - stick to simple meals and avoid fatty or spicy foods. Taking sulfasalazine after meals may help.
- Diarrhea - Drink plenty of fluids, such as water or pumpkin, to avoid dehydration. Signs of dehydration include: urinating less than usual or dark, strong-smelling urine. Do not take any other medicines for diarrhea without talking to your pharmacist or doctor.
- Stick to simple meals and avoid fatty or spicy foods. Taking sulfasalazine after meals may help. If you are sick, try sipping water to avoid dehydration. Signs of dehydration include: passing less urine than usual or dark urine with a strong odor.
- Stomach (abdomen) pain - eating and drinking slowly, and eating smaller and more frequent meals can help. Applying a heating pad or closed hot water bottle to the abdomen can also help.
- feeling of dizziness - sit down for a while until the feeling passes. Do not drive, ride a bicycle, or use tools or machinery until you feel better.
- headache, joint pain and aches - drink plenty of water and ask your pharmacist to recommend a suitable painkiller. If your headache or pain persists or is severe and painkillers do not help, tell your doctor.
- itching or mild rash - taking antihistamines, which you can buy at a pharmacy, may help. Ask your pharmacist which type is right for you.
- cough, mouth pain, or taste changes (metallic taste and change in sweet taste) - try chewing sugar-free gum. If you have a cough, try drinking water or other unsweetened beverages frequently.
- Sleep problems - avoid heavy meals, smoking, or drinking alcohol, tea, or coffee in the evening. Try not to watch TV or use your mobile phone before bed. Instead, try to relax an hour before bed.
- ringing in the ears (tinnitus) - see a doctor if it lasts longer than 2 days.
Interactions with other drugs
Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share the list with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.
Some products that may interact with this drug include: digoxin, folic acid, methenamine, PABA taken by mouth.
Sulfasalazine is very similar to mesalamine. Do not take mesalamine medications by mouth while using sulfasalazine.
This medication may interfere with certain lab tests (eg, urine normetanephrine levels, liver function tests), possibly causing false test results. Make sure lab personnel and all your doctors know you take this drug.
During therapy, it is important to drink plenty of fluids and avoid taking the drug on an empty stomach or with antacids.
Sulfasalazine may interfere with the absorption of folic acid, so you should also take folic acid (1 mg daily) while taking the medicine, and if you are pregnant, you should take 2 mg folic acid daily.
Storage conditions
Store at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications out of reach of children and pets.
Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Dispose of this medication correctly when it has expired or is no longer needed. Consult your pharmacist or local waste disposal company.
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Special instructions
Sulfasalazine is yellow-orange in color. People taking it may notice that their urine, tears, and sweat take on an orange tint, which can stain clothing and contact lenses.
Attention!
To simplify the perception of information, this instruction for use of the drug "Sulfasalazine" translated and presented in a special form on the basis of the official instructions for medical use of the drug. Before use read the annotation that came directly to medicines.
Description provided for informational purposes and is not a guide to self-healing. The need for this drug, the purpose of the treatment regimen, methods and dose of the drug is determined solely by the attending physician. Self-medication is dangerous for your health.