Olumiant Drug Interactions: What to Avoid and What to Tell Your Doctor

Before starting Olumiant (baricitinib), it's essential to review all the medications, supplements, and vaccines you currently take or are planning to take. Baricitinib has serious interactions with several drug classes that can lead to life-threatening infections or dangerous increases in drug levels. Here's a complete guide to what you need to know.

Contraindicated Combinations: NEVER Take These With Olumiant

The following combinations are either explicitly contraindicated or strongly discouraged by the FDA-approved prescribing information:

Other JAK inhibitors (e.g., Rinvoq/upadacitinib, Xeljanz/tofacitinib, Jakafi/ruxolitinib): Combining two JAK inhibitors is contraindicated. The additive immunosuppressive effect dramatically increases the risk of serious infection.

Biologic DMARDs (adalimumab/Humira, etanercept/Enbrel, abatacept/Orencia, etc.): Combining Olumiant with any biologic DMARD is not recommended. These combinations carry excessive immunosuppression risk and have not been adequately studied for safety.

Potent immunosuppressants (azathioprine, cyclosporine): These combinations are explicitly not recommended due to compounded immune suppression risk.

Live vaccines: Do not receive any live vaccines while taking Olumiant. Live vaccines include MMR (measles-mumps-rubella), varicella (chickenpox), yellow fever, and some others. Get all recommended vaccinations before starting Olumiant.

Major Interactions Requiring Dose Adjustment

Probenecid (gout medication — strong OAT3 inhibitor): Probenecid significantly increases baricitinib blood levels by reducing its elimination from the body. If you take probenecid, your baricitinib dose must be reduced to 1 mg/day. Never take the standard 2 mg or 4 mg dose while on probenecid without your doctor's guidance.

Balsalazide and other strong OAT3 inhibitors: Similar to probenecid, any strong OAT3 inhibitor can increase baricitinib exposure. Discuss this with your doctor.

Interactions That Increase Infection Risk (Use With Caution)

The following medications, when used alongside Olumiant, increase the risk of serious infections due to additive immunosuppressive effects. These combinations are not automatically prohibited but require careful clinical judgment:

Methotrexate: Commonly co-prescribed with Olumiant for RA (it's used in clinical trials), but requires monitoring. Also increases GI perforation risk.

Corticosteroids (prednisone, methylprednisolone, dexamethasone): Often used as a bridge therapy in RA. Increases infection risk and GI perforation risk when combined with Olumiant.

NSAIDs (ibuprofen, naproxen, celecoxib): Increase the risk of GI perforation (tears in the stomach or intestines) when combined with Olumiant.

Ublituximab and other CD20-depleting agents: Additive immunosuppressive effects; require careful monitoring.

What About Supplements and Over-the-Counter Medications?

While there are no well-documented life-threatening interactions between Olumiant and common OTC supplements, a few points are worth knowing:

Avoid supplements that significantly suppress the immune system (e.g., high-dose echinacea as an immune booster — though its actual immunosuppressive vs. stimulating effects are debated)

Tell your doctor about any herbal supplements — some interact with medication metabolism pathways

OTC NSAIDs (ibuprofen, naproxen) should be used cautiously — if you take them regularly, discuss with your doctor

What About Vaccines?

Because Olumiant weakens your immune system, vaccine timing is important:

Before starting Olumiant: Update all vaccinations, including the shingles vaccine (Shingrix is preferred — it's not a live vaccine), flu vaccine, COVID-19 booster, and pneumococcal vaccine.

While on Olumiant: Inactivated (non-live) vaccines like flu shots, COVID-19 vaccines, and pneumonia vaccines are safe. Live vaccines (MMR, live-attenuated flu spray, varicella, yellow fever) are not recommended.

What to Tell Your Doctor Before Starting Olumiant

Give your prescriber a complete list of everything you take — including:

All prescription medications, including other DMARDs or biologics

OTC pain relievers and anti-inflammatories (ibuprofen, naproxen, aspirin)

Any medications for gout — particularly probenecid

Supplements, vitamins, and herbal products

Any recent or upcoming vaccines

The Bottom Line

The most critical interactions to remember with Olumiant are: no other JAK inhibitors, no biologic DMARDs, no azathioprine or cyclosporine, no live vaccines, and reduce the dose to 1 mg/day with probenecid. For a complete guide to Olumiant's safety profile, see Olumiant side effects: what to expect and when to call your doctor. If you need help finding your Olumiant at a specialty pharmacy, visit medfinder.