What to Know About Rayos (Prednisone) for Rheumatoid Arthritis

A delayed-release corticosteroid for RA

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Rayos (delayed-release prednisone) is a delayed-release formulation of low-dose prednisone, which is a corticosteroid. In 2012, this oral drug gained U.S. Food and Drug Administration (FDA) approval as a treatment for rheumatoid arthritis (RA). It's also used to treat several other conditions. Prednisone has been on the U.S. market since 1955.

In autoimmune diseases, including RA, the immune system mistakenly launches an attack on healthy tissue. Prednisone is a common treatment for RA because it counters inflammation.

Rayos is known in Europe by the brand name Lodotra. So far, it's not available in generic forms or under other brand names.

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In RA, the joints are the primary target for an immune system gone awry. The immune response triggers inflammation in the joints, which leads to pain, limited range of motion, and, eventually, permanent damage.

Early, aggressive treatment can prevent or delay permanent damage and the disability associated with this condition, and corticosteroids like Rayos can be a useful part of that treatment.

Rayos works differently than immediate-release prednisone. Due to Rayos's formulation, taking the drug before bed allows it to take effect in the middle of the night—when certain cells in the immune system, called cytokines, start to increase. This mechanism of action appears to provide better control of cytokine-related inflammation for some people.

Rayos and other types of prednisone are typically used for short-term relief of inflammation. The American College of Rheumatology guidelines from 2021 state that steroids should be used for 3 months or less in the treatment of RA, and at the lowest effective dose.

Rayos is also FDA-approved for reducing the inflammatory response for people who have organ transplantation and for treating many conditions, including other rheumatologic diseases, dermatologic issues, endocrine conditions, gastrointestinal disorders, respiratory diseases, infectious diseases, and more.

Besides RA, rheumatologic conditions Rayos may be used for include:

Your healthcare provider may consider Rayos for you if you've recently been diagnosed with RA and are waiting to see the effects of a disease-modifying anti-rheumatic drug (DMARD) such as methotrexate, sulfasalazine, or hydroxychloroquine. The effects of DMARDs can take weeks or months to become evident, so prednisone and other corticosteroids play an important role during that time.

Later in the course of the disease, you may be given Rayos during RA symptom flares to help get your inflammation under control quickly.

Before Taking

Before taking Rayos, tell your healthcare provider if you've ever had an allergic reaction to prednisone, similar drugs, or any of the active ingredients in Rayos.

Also, be sure to mention whether you've had recent or ongoing infections and whether you've recently had any vaccines.

Always be sure your practitioner knows all the treatments you're using, including prescription drugs, over-the-counter medications, and supplements. This can help you avoid dangerous side effects and interactions that may be caused by certain combinations of therapies.

Precautions and Contraindications

People with certain health conditions shouldn't take Rayos, may need special monitoring while they're on it, or may need to discontinue other over-the-counter or prescription medications before taking Rayos.

Be sure to tell your healthcare provider if you have:

You shouldn't start taking prednisone while you're pregnant, if you're trying to conceive, or while you have an infection.

Other Corticosteroids

It is usually not recommended to take more than one steroid drug at a time. Corticosteroids have been around a long time, and many of them are sold under numerous brand names. Because of this, they're often best known by their generic names.

Generic names of corticosteroid drugs include:

Some of these are primarily taken orally, while others may be used topically or taken via injection. Some are available in multiple forms.


Rayos is available in delayed-release tablets of 1 milligram (mg), 2 mg, and 5 mg strengths. Your healthcare provider should determine the correct dosage for you based on several factors, including your disease severity and whether you've been using immediate-release prednisone.

Typically, the starting dose is 5 mg of Rayos once a day. However, if you've been taking rapid-release prednisone, prednisolone, or methylprednisolone, you should be given an equivalent initial dose of Rayos. This may not be the same in milligrams, but it will be the same in strength.

You should remain on the lowest amount that's effective for your symptoms.

Don't stop taking Rayos without talking to your practitioner. When going off of long-term or high-dose Rayos, you should do so gradually to avoid withdrawal effects. Your healthcare provider can advise you on how to properly taper this medication.

How to Take and Store

Rayos should be taken daily and with food. The pill must be swallowed whole—not cut, broken, or chewed—as this will interfere with the rate of release. Because the drug begins to get released four hours after taking the pill, it's commonly taken before bed.

Rayos should be stored at about room temperature, with the optimal temperature of 77 degrees F.

If you're carrying the medication with you while you're away from home, short stints of temperatures down to 59 degrees F and up to 86 degrees F are acceptable. You should keep Rayos tablets away from light and moisture.

Side Effects

As with any drug you are considering taking, Rayos's benefits must be weighed against potential side effects.


The most common side effects of Rayos include:

  • Fluid retention
  • Elevation in blood pressure
  • Change in glucose tolerance
  • Mood changes
  • Weight gain
  • Increased appetite

If any of these side effects become severe or don't go away with time, talk to your healthcare provider.


More severe side effects are possible with Rayos and can have wide-ranging effects.

If you experience any new symptoms while taking this medication, contact your healthcare provider right away.

Need for Monitoring

While you're on Rayos, you'll need to be monitored for suppression of the hypothalamic-pituitary-adrenal (HPA) axis (your body's stress-response system), Cushing's syndrome, and high blood sugars (hyperglycemia). Your blood pressure, sodium levels, and potassium levels should be closely watched as well. Be sure to get all of the tests your healthcare provider suggests and to do so on schedule.

Warnings and Interactions

This drug will make you more susceptible to new infections and could cause a reactivation of latent chronic infections, so it's especially important to tell your healthcare provider about any symptoms of infection (e.g., fever, chills, sore throat).

In addition, you should not get live or live-attenuated vaccines while taking an immunosuppressive dose of prednisone.

Pregnant or Nursing Women

Taking Rayos during the first trimester of pregnancy can harm your baby. It's associated with an increased risk of cleft lip and cleft palate, restricted growth, small birth weight, and premature birth. In animals, it's also been associated with miscarriages.

This drug does pass into breast milk and may cause problems with your child's growth and development.

You and your healthcare provider should carefully weigh the benefits of this drug with the serious risks it poses to your baby.

Drug Combinations

Prednisone can negatively interact with a long list of drugs and supplements, including common over-the-counter products such as:

Some common classes of drugs that can cause problems with Rayos are:

You and your healthcare provider need to carefully evaluate the potential risks and benefits of Rayos before you start taking it, as your health changes over time, and whenever you start new medications.

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4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. Kim D, Choi CB, Lee J, et al. Impact of early diagnosis on functional disability in rheumatoid arthritisKorean J Intern Med. 2017;32(4):738-746. doi:10.3904/kjim.2015.364

  3. Palmsten K, Bandoli G, Watkins J, Vazquez-Benitez G, Gilmer TP, Chambers CD. Oral corticosteroids and risk of preterm birth in the California Medicaid program [published online ahead of print, 2020 Aug 11]. J Allergy Clin Immunol Pract. 2020;S2213-2198(20)30805-9. doi:10.1016/j.jaip.2020.07.047

  4. National Institutes of Health, U.S. National Library of Medicine: MedlinePlus. Prednisone.

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