Sulfasalazine

Generic name: Sulfasalazine
Dosage form: oral tablet, oral delayed-release tablet

Usage of Sulfasalazine

Sulfasalazine is a disease-modifying anti-rheumatic drug (DMARD) used to treat and manage autoimmune diseases including rheumatoid arthritis and an inflammatory bowel disease called ulcerative colitis. It is a slow-acting DMARD, taking time to build up and start working.

Sulfasalazine helps to reduce pain and swelling and lowers inflammation in your body. It limits the damage that rheumatoid arthritis causes to your joints, helping to prevent disease progression.

Sulfasalazine consists of the anti-inflammatory agent 5-aminosalicylic acid (5-ASA, mesalamine or mesalazine) and the antibiotic sulfapyridine, which are linked by a bond.

It's not fully understood how sulfasalazine works. Sulfasalazine is too big to be absorbed by your small intestine, but bacteria in your colon can break the bond between 5-ASA and sulfapyridine, which frees 5-ASA to work locally in your colon to help in ulcerative colitis. Sulfasalazine and its metabolites - the other drugs that it is broken down into - are also thought to have a range of immunomodulatory effects. They block or inhibit certain processes in your body, which helps to reduce the activity of your immune system.

Sulfasalazine has been used since the 1950s. The US Food and Drug Administration (FDA) has approved a standard tablet (Azulfidine) and an enteric-coated, delayed-release tablet (Azulfidine EN-tabs) of sulfazalazine. Generic versions of these tablets are also available.

The delay-release, enteric-coated tablets are recommended for people who experience gastrointestinal side effects such as nausea and vomiting.

Sulfasalazine side effects

See "Important information" above.

The most common side effects of sulfasalazine are:

anorexia

headache

nausea

vomiting

gastric distress

reversible oligospermia.

Less frequent side effects are:

skin rash

pruritus

urticaria

fever

Heinz body anemia

hemolytic anemia

cyanosis

Sulfasalazine may also produce an orange-yellow discoloration of the urine or skin.

These are not all the possible side effects of sulfasalazine. For more information, ask your doctor or pharmacist.

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Before taking Sulfasalazine

Tell your doctor if you are pregnant or plan to become pregnant. A study suggests that treatment with sulfasalazine is not associated with fetal malformation. However, neural tube defects have been reported in some infants born to mothers taking sulfasalazine during pregnancy. This may be linked to the drug's ability to inhibit the absorption and metabolism of folic acid. Sulfasalazine and sulfpyridine pass through the placenta. It is recommended that sulfasalazine is only used during pregnancy if clearly needed.

Tell your doctor if you are breastfeeding or planning to breastfeed. Sulfasalazine and its metabolite pass into breast milk and can lead to a type of brain damage called kernicterus in newborns. Limited data also suggests it may cause infants to develop bloody stools or diarrhea. Sulfasalazine should be used with caution in people who are breastfeeding. Talk to your doctor about the best way to feed your baby while on sulfasalazine.

How to use Sulfasalazine

The dose of sulfasalazine should be adjusted for each patient depending on their response and tolerance to the drug

Ulcerative Colitis

Initial Therapy The recommended dose for adults is sulfasalazine 3 to 4 g daily in evenly divided doses with dosage intervals not exceeding eight hours. A lower dose of 1 to 2 g may also be used to reduce the risk of gastrointestinal side effects. The recommended dose for children ≥ 6 years of age is 40 to 60 mg/kg of body weight in each 24-hour period, divided into 3 to 6 doses.

Maintenance Therapy The recommended dose for adults is sulfasalazine 2 g daily. The recommended dose for children ≥ 6 years of age is 30 mg/kg of body weight in each 24-hour period, divided into 4 doses.

Rheumatoid arthritis

The recommended dose for adults is 2 g daily in two evenly divided doses. Initially, a lower dose of 0.5 to 1 g daily should be used to reduce the risk of gastrointestinal side effects. A suggested dosing schedule is given below. Suggested Dosing Schedule for Adult Rheumatoid Arthritis: Week of treatment Morning No. of 500 mg tablets Evening No. of 500 mg tablets 1 - 1 2 1 1 3 1 2 4 2 2

Juvenile Rheumatoid Arthritis - polyarticular course

The recommended dose for children ≥ 6 years of age is 30 to 50 mg/kg of body weight daily in two evenly divided doses. Typically, the maximum dose is 2 g per day. Initially a dose of a quarter to a third of the planned maintenance dose should be used and increase weekly until reaching the maintenance dose at one month. This reduces the risk of gastrointestinal side effects.

See full prescribing information for further information about sulfasalazine dosing.

Warnings

Sulfasalazine can cause serious side effects including:

Hepatic, renal, and hematologic toxicity or other conditions Treatment with sulfasalazine has been reported to cause hypersensitivity reactions, agranulocytosis, aplastic anemia, other blood dyscrasias, renal and liver damage, irreversible neuromuscular and central nervous system changes, and fibrosing alveolitis, and these side effects have been linked to the death of some patients. Tell your doctor if you get a sore throat, fever, pallor, purpura, or jaundice while taking sulfasalazine. These symptoms may be signs of a serious blood disorder or hepatotoxicity (liver toxicity). Complete blood counts and urinalysis should be done frequently while on sulfasalazine. Treatment should be stopped while waiting for blood test results.

Oligospermia and Infertility Treatment with sulfasalazine may cause oligospermia (low sperm count) and infertility in men. Stopping sulfasalazine appears to reverse these effects.

Serious Infections Treatment with sulfasalazine may cause serious infections, including fatal sepsis and pneumonia. Tell your doctor straight away if you develop signs of an infection. Sulfasalazine treatment should be stopped if you develop a serious infection. Tests for infection and myelosuppression should be done if an infection is suspected.

Hypersensitivity Reactions Treatment with sulfasalazine may cause severe hypersensitivity reactions which may include internal organ involvement, such as hepatitis, nephritis, myocarditis, mononucleosis-like syndrome, hematological abnormalities, and/or pneumonitis including eosinophilic infiltration.

Severe Cutaneous Adverse Reactions

Drug Reactions with Eosinophilia and Systemic Symptoms (DRESS) Treatment with sulfasalazine can cause severe, life-threatening, systemic hypersensitivity reactions such as drug reaction with eosinophilia and systemic symptoms (DRESS). Early signs of such a reaction include fever or swollen lymph nodes (lymphadenopathy) and these may be seen even if a rash hasn't developed yet. Tell your doctor straight away if you develop signs of systemic hypersensitivity. Treatment with sulfasalazine should be stopped if another reason for your symptoms can't be identified.

Other Severe Cutaneous Adverse Reactions Treatment with sulfasalazine can cause other severe cutaneous adverse reactions, including exfoliative dermatitis, Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN), and acute generalized exanthematous pustulosis (AGEP). Severe cutaneous adverse reactions can be serious and are sometimes fatal. You are at highest risk for these events early in therapy, with most events occurring within the first month of treatment. Tell your doctor straight away if you develop symptoms of a severe cutaneous adverse reaction. Treatment with sulfasalazine should be stopped at the first sign of such reactions.

What other drugs will affect Sulfasalazine

Tell your doctor about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.

Especially tell your doctor if you take medicines that contain digoxin or folic acid. Sulfasalazine may reduce your absorption of these drugs. Sulfasalazine used in combination with methotrexate may increase your risk of gastrointestinal adverse events, especially nausea.

Know the medicines you take. Keep a list of them to show your doctor and pharmacist when you get a new medicine.

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