Sulfasalazine is the only drug that was developed specifically for arthritis and combines a sulfa drug with acetylsalicylic acid. Sulfasalazine is a favorite drug for inflammatory arthritis in Europe, and has been used for rheumatoid arthritis since the 1960s. It has been used for psoriatic arthritis since the 1970s. There are several clinical trials using sulfasalazine, showing a modest improvement over placebo. However, in individuals who cannot take methotrexate, it is the drug of choice. It does not have a specific indication for psoriatic arthritis.

Mechanism of action

Sulfasalazine helps control symptoms and signs of inflammation, and may help the skin, but there is not enough information on its effect on the psoriasis. The exact mechanism of action is unknown.

Mode of administration

Sulfasalazine is provided as a tablet of 500 mg, and usually 4 a day (2gm) is necessary. The effect is usually noted within 8-12 weeks. However, some patients require a dose of 3-4 gm per day.

Side effects

People with an allergy to sulfa drugs should not take sulfasalazine. Some patients taking sulfasalazine develop an allergic reaction manifesting with a sever rash. The major side effect of sulfasalazine is diarrhea, which usually disappears with use, and suppression of the bone marrow to cause a low white count and thus predisposition to infection. Hematological blood tests (to check the white blood cell count) should be performed at regular intervals (2-3 months) in people taking sulfasalazine. The drug is stopped when side effects are noticed and the white count usually returns to normal.

Use in pregnancy

There have been successful pregnancies on sulfasalazine. However, it is recommended that women who are on sulfasalazine and are contemplating pregnancy discuss this with their physicians.