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 refined his theories to suggest that rheumatic diseases were immunologic reactions of antigens (in this case, mycoplasmas) and antibodies. 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. Don Miller, PharmD, pharmacist, and professor and chair of the pharmacy practice department at North Dakota State University 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, in general, are inexpensive, widely available, and easy to administer.

The antibiotic protocol does require patience; like other slow-acting DMARDs (such as hydroxychloroquine, methotrexate or sulfasalazine), 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 fairly 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, photosensitivity, discolored teeth or fingernails, dark pigmentation of the skin or a lupus-like syndrome.

John Stone, MD, MPH, a rheumatologist 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.”

As with all drugs, antibiotics have benefits and risks, which you and your doctor need to weigh before setting a course of action that is right for you.