Minocycline is an antibiotic that reduces inflammation. Doctors usually use minocycline to treat bacterial infections such as pneumonia, but one off-label use includes treating rheumatoid arthritis (RA).
Although its intended purpose is to help treat bacterial infections, doctors have also used it as a disease-modifying anti-rheumatic drug (DMARD). In general, DMARDs can improve the symptoms of RA and prevent long-term disabilities. However, doctors may prescribe newer treatments for the condition more often.
This article examines minocycline as a treatment for RA, its effectiveness and side effects, and other standard therapies.
Evidence from research suggests that minocycline
- joint swelling and tenderness
- markers of inflammation
Although minocycline can reduce redness, swelling, and tenderness, it does not entirely stop RA from worsening. Studies do not show significant improvement in fatigue, joint pain, or joint damage.
Doctors use minocycline sparingly to treat RA. Newer agents and other DMARDs are more effective in reducing RA symptoms and slowing progression. Researchers have also studied it less than other treatment options. If doctors use minocycline, it likely will be combined with other medications to treat RA.
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RA is an immune system disease that causes body defense cells to accidentally attack bones and joints. This causes injury to tissue from inflammation. Once inflammation starts, it produces many damaging proteins and cell types. This results in twisted and painful joints.
These cell types and proteins fuel the process of inflammation, but the specifics of these processes can vary between inflammatory conditions. The amount of inflammation determines the type of therapy needed to control the symptoms. The same level of inflammation, however, can respond differently to different treatments.
Doctors typically use minocycline as an antibiotic to treat a wide variety of bacterial infections. Although it is an antibiotic, minocycline can ease RA symptoms in ways not directly related to its antibiotic properties.
Minocycline has fewer adverse effects than other drugs that treat RA.
However, some adverse effects of minocycline can include:
People may notice discolored nails and darker skin on the arms and legs called hyperpigmentation. This usually happens in areas of previous injuries or with long-term minocycline use. Minocycline may also discolor tooth enamel in children who are still developing teeth.
Although minocycline is effective in treating a range of autoimmune conditions, in very rare cases, it can cause immune system problems such as lupus, Stevens-Johnson syndrome, and ANCA vasculitis. These conditions can involve redness, swelling, and pain in the skin, muscles, tissues, or joints. Fever of unknown cause is also a hallmark of these autoimmune conditions.
Other rare adverse reactions can include liver, lung, or kidney inflammation.
The main treatment options for RA can include:
A doctor will determine what to prescribe based on how long the person has had RA and the severity of their symptoms. They may add or switch drugs if a person’s symptoms worsen.
DMARDs, a collection of unrelated drugs, form the foundation of RA treatment. The most common DMARDs are:
Doctors may suggest using different DMARDs alone or, for quicker results, start combination therapy — methotrexate plus sulfasalazine plus hydroxychloroquine.
Doctors should check the therapy after 3 months to determine the effectiveness of the treatment and make changes if needed.
Biological agents fall into two classes: tumor necrosis factor (TNF) inhibitors and non-TNF.
The following drugs are in the TNF inhibitor class:
- adalimumab (Humira)
- certolizumab pegol (Cimzia)
- etanercept (Enbrel)
- golimumab (Simponi)
- infliximab (Remicade)
These drugs block the damaging action of the protein TNF in the joints.
The guidelines recommend these drugs for people with moderate or severe cases of RA. Often, doctors recommend these drugs for people with RA who have progressed beyond DMARD treatment.
Doctors should combine TNF inhibitors with methotrexate to improve their benefits when possible.
The following drugs are in the non-TNF class:
Kevzara and Actemra may hinder the activity of the protein interleukin-6, which reduces inflammation. Rituxan can cancel out B-cells that can cause damage and swelling. Orencia can stop T-cells from producing antibodies that attack joints.
JAK inhibitors interrupt the signals within cells that produce inflammatory proteins called cytokines. Stopping these signals halts cytokine production and suppresses inflammation. This class includes:
Glucocorticoids are a type of steroid hormone. They work by suppressing the immune cells responsible for inflammation. This reduces inflammation in the body.
Doctors can use a variety of glucocorticoids to treat RA. The dosages and length of treatment may vary depending on the severity of the condition. People tend to get the best results from using glucocorticoids for short periods of time to treat flareups.
People with RA rarely use glucocorticoids for longer than 3 months due to the adverse effects they cause, such as infections and osteoporosis.
Over the past 20 years, gaining official approval of biological agents and developing a better understanding of DMARDs has changed the face of RA treatment. These changes have placed minocycline outside the circle of standard treatment options for RA.
Researchers have stopped investigating minocycline to treat RA. The most recent guidelines do not recommend minocycline as other options are more beneficial. Minocycline now plays a small and retreating role in the treatment of RA.