Can Antibiotics Help Treat RA?

Using antibiotics to treat rheumatoid arthritis is not considered a first-line treatment, but for some, it may be effective.


There are those who swear by it and others who are skeptical. Here, we will talk to experts and examine the research to find out just how and where antibiotics fit in as a treatment option for rheumatoid arthritis (RA).

Minocycline, a drug in the tetracycline class, is the antibiotic most studied for use in RA and is generally the standard oral antibiotic prescribed for such patients, although it is not FDA-approved for this use. While much more research is needed in this area, the few clinical studies that have been done suggest that minocycline may be a safe, effective treatment option for some patients with RA, especially when taken early in the course of the disease.

The most comprehensive study of minocycline use in patients with RA to date, known as the MIRA (Minocyline in Rheumatoid Arthritis) study, was done in 1995 on 219 patients with active RA. After studying the evidence gathered from this 48-week, double-blind, placebo-controlled study, researchers concluded “minocycline was safe and effective for patients with mild to moderate RA.” A four-year follow-up study of 46 of the original MIRA participants reaffirmed the finding that “minocycline appears to be an effective therapy for early RA.”

These results (along with results from a limited number of other studies) suggest there is a small portion of the population of people with RA who may benefit from minocycline. According to the American College of Rheumatology (ACR) 2012 Recommendations for the Use of Nonbiologic and Biologic Disease-Modifying Antirheumatic Drugs in Rheumatoid Arthritis, “minocycline monotherapy was recommended for patients without poor prognostic features with low disease activity and with short disease duration (less than 24 months).” A very small group of people with RA fall into this category.

Why Minocycline Isn’t Widely Used

Because the window of opportunity to achieve remission in people with RA is limited, rheumatologists usually recommend aggressive therapy early in the course of the disease to halt disease progression and prevent permanent joint damage. In general, minocycline therapy is a relatively weak treatment when compared with most first- and second-line therapies. As a result, minocycline is not widely prescribed, even among the limited population of patients with RA who fit the ACR criteria noted above.

The limited research that does exist suggests minocycline can provide some benefit for some people with RA. But minocycline has simply not been studied enough in people with RA to provide a full picture of its effectiveness and limitations. As a comparison, methotrexate, a standard, frequently used RA medication, has been studied in more than 800 clinical trials, versus minocyline in about 15. 

How Minocycline Works

Using antibiotics to combat RA is not new. In the late 1930s, Thomas McPherson Brown, MD, theorized that RA and other rheumatic disorders begin with an infection by unusual organisms later given the name mycoplasmas. Dr. Brown hypothesized that illnesses of this nature could be treated with antibiotics.

Current research suggests that in addition to their antimicrobial properties, the tetracycline class of drugs appears to have anti-inflammatory and cartilage-protective effects. Donald Miller, PharmD, professor of pharmacy practice at North Dakota State University in Fargo clarifies, “It isn’t the antibiotic properties, but the effects on the immune system and the ability to inhibit enzymes that break down cartilage and connective tissue that make minocycline (and other tetracycline drugs) effective.”

Treatment Considerations

Drug tolerance (the body’s diminishing response to a drug after prolonged exposure) does not appear to be a problem with tetracycline antibiotics. Additionally, antibiotics are inexpensive, widely available and easy to administer.

The antibiotic protocol does require patience; like other slow-acting DMARDs, results may not show until six or more months into treatment — and by then, irreversible joint damage may have occurred.

Side effects of minocycline are generally mild, the most common being upset stomach, headaches and dizziness. Some patients may become sun sensitive and experience more serious side effects, such as rashes, discolored teeth or fingernails, dark pigmentation of the skin or a lupus-like syndrome.

John Stone, MD, director of clinical rheumatology at Massachusetts General Hospital in Boston, says, “There are so many other good options for treating RA that really work and really prevent joint damage that I would not encourage anyone with true RA to take tetracycline antibiotics. Antibiotics aren’t candy — they have potential side effects, too — and I think their effect in RA is minimal.”

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