The approach to treating inflammatory forms of arthritis depends on several factors. These include the type of arthritis, the experience of the practitioner, the age of the patient, potential confounding factors such as allergies, length of time the patient has had the arthritis, previous drugs tried, and whether the drugs are to be used one at a time or "layered" on top of each other.
For example, a disease like rheumatoid arthritis demands aggressive treatment with a disease modifying anti-rheumatic drug (DMARD) such as methotrexate. Methotrexate tends to work well to slow disease. However, initiation of methotrexate is just the first step. This is quickly followed by either the addition of a biologic medicine or by adding other DMARDs.
In contrast, a disease like psoriatic arthritis may or may not respond to methotrexate. So a different disease modifying anti-rheumatic drug is required. And that's where a medicine like sulfasalazine has utility.
Sulfasalazine was manufactured originally by combining an antibiotic, sulfapyridine, with an anti-inflammatory drug 5-aminosalicylic acid. The latter, as the reader might surmise, is a form of aspirin.
This was done because many years ago it was felt that rheumatoid arthritis was an infectious disease so an antibiotic coupled with an anti-inflammatory drug made sense as a drug that would be useful to treat rheumatoid arthritis. And, it has been shown in a number of studies to be effective in rheumatoid arthritis acting as a DMARD. Its effects are relatively mild.
It is an oral drug taken daily. Roughly one-third of sulfasalazine is absorbed from the gut. The remainder is broken down into its component chemicals, sulfapyridine and 5-aminosalicylic acid. Sulfapyridine is absorbed from the gastrointestinal tract and the 5-aminosalicyclic acid is excreted.
Sulfasalazine (trade name, Azulfidine) has immunomodulatory effects on cells that propagate inflammation. Often sulfasalazine is combined with biologic therapy or it is sometimes combined with methotrexate and hydroxychloroquine (Plaquenil) or azathioprine (Imuran) in patients with rheumatoid arthritis. The exact use generally depends on the experience of the practitioner.
Where it seems to be more effective is in the other inflammatory forms of arthritis such as psoriatic arthritis, ankylosing spondylitis, and certain forms of juvenile arthritis. Why this is, no one knows.
Sulfasalazine does have potential side effects including elevated liver function tests, bone marrow suppression, skin rashes, and lowered white blood cell count.
Because it is a sulfa based drug, it should not be used in patients with a sulfa allergy.