Psoriatic arthritis (PsA) is a progressive, inflammatory disease that should be treated to relieve symptoms and prevent joint damage.

JAK inhibitors are a newer form of treatment that targets the immune system. They can effectively prevent or reduce symptoms, decrease inflammation, and keep PsA from getting worse.

Because they’re so new, you may have questions about what JAK inhibitors are, how they work, and how they compare to other treatments for PsA.

The following are some answers to the most frequently asked questions so you can better understand JAK inhibitors.

JAK inhibitors are a type of small molecule, disease-modifying antirheumatic drug (DMARD). They provide targeted therapy for autoimmune disorders such as PsA.

According to a 2021 study among others, JAK inhibitors can reduce symptom severity and slow disease progression.

As of 2022, only two JAK inhibitors have Food and Drug Administration (FDA) approval for PsA treatment. The FDA first approved tofacitinib (brand name Xeljanz) for PsA in 2017 and then approved upadacitinib (brand name Rinvoq) in December 2021.

Though both biologics and JAK inhibitors are a part of the DMARD category, they’re separate medications. Both work to target specific portions of the immune system to suppress PsA symptoms.

Biologics are a type of medication that comes from living organisms or cells. They target and block specific proteins within the immune system, including tumor necrosis factor-alpha (TNF-alpha), interleukin 17-A, or interleukins 12 and 23.

Unlike JAK inhibitors, which come in pill form, biologics come as either injections or infusions. Your doctor may prescribe them for moderate to severe cases of PsA or if you don’t respond well to other forms of treatment.

JAK inhibitors are a small molecule medication, and they’re made with synthetic substances. Like biologics, JAK inhibitors block proteins in the immune system. JAK inhibitors block the proteins in what’s known as the JAK-STAT signaling pathway.

JAK inhibitors do have some side effects, though you may not experience any.

Commonly reported side effects of JAK inhibitors include:

  • nausea
  • headaches
  • increased cholesterol levels
  • indigestion
  • diarrhea
  • upper respiratory tract infection

Less commonly, you may experience more serious side effects, such as:

  • abnormal blood counts
  • abnormal liver function tests
  • infection
  • increased risk of bowel perforation
  • decrease in kidney function

If you notice any severe side effects or side effects worsen and don’t improve over time, consider speaking with your doctor. They may be able to recommend a different treatment.

JAK inhibitors do suppress the immune system as a means of controlling PsA symptoms.

Evidence suggests that the most commonly reported side effect is upper respiratory infections, which indicates that you may become more susceptible to infections.

You should let your doctor know if you’re living with any other condition that might be affected by JAK inhibitors, such as:

  • blood disorder
  • liver disease
  • history of active tuberculosis
  • kidney disease
  • cancer
  • active infection

JAK inhibitors are the newest form of PsA medication, but evidence suggests they may be one of the safest treatment methods.

According to a 2022 review of studies, there’s very little difference between biologics and JAK inhibitors in terms of safety and reported side effects.

Both medications can increase your risk of infection, particularly an upper respiratory infection.

Neither biologics nor JAK inhibitors are the most commonly prescribed medication for PsA. Methotrexate is another type of DMARD that prevents cells from dividing. Though it can be effective and inexpensive, it may also lead to serious side effects, such as toxicity.

More common side effects of methotrexate can include:

  • stomach cramping
  • nausea
  • soreness at the injection site
  • lightheadedness
  • vomiting
  • depression

JAK inhibitors are the newest form of treatment for PsA. They are a type of disease-modifying antirheumatic drug (DMARD) that targets the immune system to prevent inflammation, symptoms, and disease progression.

Though JAK inhibitors are generally safe and effective, they can cause side effects including upper respiratory infections. Talk with your doctor about whether you should try JAK inhibitors for treating psoriatic arthritis.