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 RA.

Minocycline, a drug in the tetracycline class, is the antibiotic most studied for patients with rheumatoid arthritis 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 performed 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 clinical results (along with results from a limited number of other studies) suggest that there is a small portion of the population of patients with RA who may benefit from minocycline. According to the American College of Rheumatology (ACR) 2012 Update of the 2008 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 patients with RA is very small, rheumatologists almost always recommend very aggressive therapy early on 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-line 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.

Graciela Alarcón, MD, MPH, Jane Knight Lowe chair of medicine in rheumatology (Emeritus) at the University of Alabama at Birmingham, and a lead researcher in the MIRA study explains why minocycline isn’t prescribed more widely for patients with RA: “It is hard to justify not being more aggressive from the onset of the disease because other therapies [are] more effective.”

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, how it works, when it should be administered and in what dosages for optimal effects, and for whom it is best suited. As a comparison, methotrexate, a standard, frequently used RA medication, has been studied in more than 800 clinical trials, versus minocyline in about 15.