7 mins read

Sulfasalazine is used to treat certain inflammatory conditions, such as ulcerative colitis and rheumatoid arthritis. The most common side effects are loss of appetite, headache, nausea, vomiting, stomach pain, and skin rashes. Rarely, sulfasalazine can cause kidney stones. It is important to drink plenty of liquid while taking sulfasalazine to reduce this risk.

Uses

What is sulfasalazine used for?

Sulfasalazine is commonly used to treat the following conditions.

Sulfasalazine may also be used for other conditions as determined by your health care provider.

How does sulfasalazine work (mechanism of action)?

Sulfasalazine works by reducing inflammation in your body.

How is sulfasalazine supplied (dosage forms)?

Brands and other names

  • Azulfidine
  • Azulfidine EN-tabs

Dosage forms and strengths

  • 500 mg delayed-release oral tablets
  • 500 mg oral tablets

How should I store sulfasalazine?

Sulfasalazine should be stored at room temperature, between 68 F and 77 F (20 C and 25 C). It can be exposed to temperatures between 59 F and 86 F (15 C and 30 C) for shorter periods of time, such as when transporting it. Store it in a cool, dry place.

Side Effects

What are the most common side effects of sulfasalazine?

The most common side effects of sulfasalazine are listed below. Tell your health care provider if you have any of these side effects that bother you.

  • Loss of appetite
  • Headache
  • Nausea or vomiting
  • Stomach pain
  • Skin rash
  • Low sperm counts

There may be other side effects of sulfasalazine that are not listed here. Contact your health care provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088 (800-332-1088). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of sulfasalazine?

While less common, the most serious side effects of sulfasalazine are described below, along with what to do if they happen.

Severe Allergic Reactions. Sulfasalazine may cause allergic reactions, including a specific type of allergic reaction called DRESS. DRESS stands for drug reaction with eosinophilia and systemic symptoms. It is also sometimes called multi-organ hypersensitivity. This is a reaction that can affect multiple parts of the body, including your liver, kidneys, and heart. Stop taking the medicine and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Itching, skin rash, or pale red bumps on the skin called hives
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Shortness of breath, trouble swallowing, or throat tightness
  • Swelling in your feet, ankles, or legs
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain
  • Dark-colored pee
  • Your skin or the whites of your eyes turning yellowish in color (also called jaundice)

Severe Skin Reactions. Sulfasalazine can cause severe skin reactions, called Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN), and acute generalized exanthematous pustulosis (AGEP) that can lead to death if not treated. If you develop a rash, stop taking sulfasalazine and call your health care provider right away. Get emergency help if you have any of the following symptoms.

  • Painful red or purple skin that looks burned and peels off
  • Flat red rash or blisters on your skin, mouth, nose, and genitals
  • Red, painful, watery eyes

Inflammation of the Heart Muscle. Myocarditis is when your heart muscle becomes inflamed or irritated. This can affect how well your heart pumps blood. Sulfasalazine can cause the immune system to cause more inflammation around the heart muscle. Contact your health care provider right away if you have chest pain, shortness of breath, or trouble breathing.

Blood Disorders. Sulfasalazine can cause blood disorders such as agranulocytosis, aplastic anemia, and others. Stop taking sulfasalazine and get help right away if you have any of the following symptoms of blood disorders.

  • Fever
  • Shortness of breath
  • Pale or yellowish skin
  • Easy bruising or bleeding
  • Frequent infection
  • Unusual weakness or tiredness
  • Dizziness, lightheadedness, or feeling like you are about to pass out
  • Headache
  • Fast or abnormal heartbeat

Infections. Sulfasalazine can increase your risk of infections, including serious infections. Call your health care provider right away if you have an infection or any of the following symptoms.

  • Burning or stinging when you pee 
  • Coughing or coughing up blood
  • Fever, sweats, chills, or muscle aches
  • Shortness of breath
  • Diarrhea or stomach pain
  • Weight loss

Kidney Damage. Kidney damage can happen when taking sulfasalazine. Call your health care provider right away if you have any of the following symptoms of kidney damage.

  • Reduced need to pee
  • Swelling in your feet, ankles, or legs
  • Weakness or unusual tiredness
  • A hard time catching your breath or chest pain/pressure
  • Confusion
  • Nausea
  • Seizures

Kidney Stones. Sulfasalazine may cause kidney stones. Drinking plenty of water can help prevent kidney stones. Tell your health care provider right away if you have severe pain in your side or back or have blood in your urine (pee). Your pee may look pink, red, or brown.

Liver Damage. Liver damage, also called hepatotoxicity, can happen when taking sulfasalazine. Call your health care provider right away if you have any of the following symptoms of liver damage.

  • Nausea or vomiting
  • Stomach or belly pain
  • Fever
  • Weakness or unusual tiredness
  • Itching
  • Loss of appetite
  • Light-colored poop
  • Dark-colored urine (pee)

Your skin or the whites of your eyes turning yellowish in color (also called jaundice)

Warnings & Precautions

Who should not use sulfasalazine?

Allergies to Ingredients. People who are allergic to any of the following should not take sulfasalazine.

  • Sulfasalazine
  • Azulfidine
  • Azulfidine EN
  • Any other medicine known as a sulfonamide or a salicylate
  • Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all of the ingredients in the specific sulfasalazine products they stock.

Sulfa Allergy. Some people who have a sulfa allergy may also be allergic to sulfasalazine. A sulfa allergy is a rash or more serious reaction to sulfa, or sulfonamide, medicines. Sulfa medicines include sulfadiazine silver, sulfamethoxazole, and sulfasalazine. Tell your health care provider if you have any allergies to medicines. Your health care provider can help you decide if it is safe for you to take sulfasalazine.

Gut Blockage. Do not take sulfasalazine if you have an intestinal obstruction, which is a blockage in your intestines.

Bladder Blockage. Do not take sulfasalazine if you have a urinary obstruction, which is a blockage in your urinary tract that makes it hard to pee.

Porphyria. Do not take sulfasalazine if you have a genetic condition called porphyria that affects your red blood cells. 

What should I know about sulfasalazine before using it?

Do not take sulfasalazine unless it has been prescribed to you by a health care provider. Take it as prescribed.

Do not share sulfasalazine with other people, even if they have the same condition as you. It may harm them.

Keep sulfasalazine out of the reach of children.

Do not chew, cut, or crush sulfasalazine delayed-release oral tablets.

The best time to take sulfasalazine is after a meal.

Make sure to drink enough liquids while taking sulfasalazine. This can help prevent kidney stones. See the Side Effects section for more details. 

Sulfasalazine may lower sperm counts, which can impact your fertility. These effects seem to be reversible after stopping the medicine. Talk to your health care provider if you have concerns about fertility while taking sulfasalazine.

Sulfasalazine may cause your skin or urine (pee) to turn orangish-yellow. Contact your health care provider if you have any concerns.

People who are 65 and older can be at a greater risk of some side effects from sulfasalazine. Talk to your health care provider about your risks if you are in this age group. Keep all of your appointments for follow-up with your health care provider, labs, or other testing. 

Sulfasalazine can make your skin more sensitive to light from the sun, sunlamps, and tanning beds. This is called photosensitivity. Exposure to this light can cause severe sunburns, blisters, and swelling. If you need to be in sunlight, wear sunscreen, a hat, and clothing that covers your skin.

What should I tell my health care provider before using sulfasalazine?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them know if sulfasalazine is right for you.

In particular, make sure that you discuss any of the following.

Current and Past Health Conditions. Tell your health care provider if you have any of the following.

  • Recurring or chronic infections
  • Immunity problems that increase your risk of infections
  • Kidney or liver problems
  • A blood disorder
  • Asthma
  • Glucose-6-phosphate dehydrogenase (G6PD) deficiency

Other Medicines and Supplements. Sulfasalazine may interact with other medicines and supplements. Before taking sulfasalazine, tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

Pregnancy. It is not known if or how sulfasalazine could affect pregnancy or harm an unborn baby. Tell your health care provider if you are pregnant or plan to become pregnant.

Breastfeeding. Sulfasalazine passes into breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed. Your health care provider will let you know if you should take sulfasalazine while breastfeeding. If you breastfeed while taking sulfasalazine, watch for diarrhea in your infant.

Interactions

Does sulfasalazine interact with foods or drinks?

There are no known interactions between sulfasalazine and foods or drinks.

It is unknown if drinking alcohol will affect sulfasalazine.

Does sulfasalazine interact with other medicines (drug interactions)?

Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are using any of the following before taking sulfasalazine.

  • Folic acid, which is used to prevent and treat low blood levels of folate
  • Digoxin (Lanoxin), which is a medicine used to treat irregular heartbeat and some types of heart failure
  • A nonsteroidal anti-inflammatory drug (NSAID), such as ibuprofen, naproxen, and others, which is in many prescription and OTC products for pain, swelling, and fever
  • Methotrexate (Trexall and others), which is a medicine commonly used for rheumatoid arthritis or certain types of cancer

This may not be a complete list of medicines that can interact with sulfasalazine. Always check with your health care provider.

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much sulfasalazine?

If you or someone else has used too much sulfasalazine, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of sulfasalazine?

If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and only take the next dose. Do not take double or extra doses.