What Is Baricitinib Used For and How Does it Work?

Baricitinib is used to treat rheumatoid arthritis.

Baricitinib is available under the following different brand names: Olumiant.

What Are the Dosages of Baricitinib?

Dosages of Baricitinib:

Dosage Forms and Strengths


  • 2 mg

Dosage Considerations – Should be Given as Follows:

Rheumatoid Arthritis

  • Indicated for adults with moderately to severely active rheumatoid arthritis (RA) who have had an inadequate response to one or more tumor necrosis factor (TNF) antagonist therapies
  • It may be used as monotherapy or in combination with methotrexate or other nonbiologic disease-modifying antirheumatic drugs (DMARDs)
  • 2 mg orally once/day

Dosage Modifications

Absolute lymphocyte count (ALC)

  • ALC 500 cells/mm3 or greater: Maintain dose
  • ALC less than 500 cells/mm3: Avoid initiation or interrupt dosing until ALC 500 cells/mm3 or greater

Absolute neutrophil count (ANC)

  • ANC 1000 cells/mm3 or greater: Maintain dose
  • NC less than 1000 cells/mm3: Avoid initiation or interrupt dosing until ANC 1000 cells/3 or greater


  • Hgb 8 g/dL or greater: Maintain dose
  • Hgb less than 8 g/dL: Avoid initiation or interrupt dosing until Hgb 8 g/dL or greater

Renal impairment

  • Moderate (eGFR 30-60 mL/min/1.73 m2): Decrease to 1 mg/day
  • Severe (eGFR less than 30 mL/min/1.73 m2): Not recommended (not studied)

Hepatic impairment

  • Mild or moderate: No dose adjustment required
  • Severe: Not recommended

Organic anion transporter 3 (OAT3) inhibitors

  • Coadministration with baricitinib and OAT3 inhibitor (e.g., probenecid): Decrease baricitinib to 1 mg/day

Dosing Considerations

  • Do not initiate if ALC is less than 500 cells/mm3, ANC less than 1000 cells/mm3, or Hgb level less than 8 g/dL
  • Avoid in patients with an active, serious infection, including localized infections
  • Before initiating, test patients for latent tuberculosis (TB); if positive, consider treating for TB before initiating

Limitations of use

  • Not recommended for use in combination with another Janus kinase (JAK) inhibitors, biologic DMARDs, or with potent immunosuppressants (e.g., azathioprine, cyclosporine)
  • Safety and efficacy not established in pediatric patients

What Are Side Effects Associated with Using Baricitinib?

Common side effects of Baricitinib include:

  • Upper respiratory tract infections
  • Nausea
  • Increased liver function tests
  • Platelet elevations
  • Herpes zoster infection

Less common side effects of baricitinib include:

This document does not contain all possible side effects and others may occur. Check with your physician for additional information about side effects.

What Other Drugs Interact with Baricitinib?

If your doctor has directed you to use this medication, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first.

  • Baricitinib has no severe interactions with other drugs.
  • Baricitinib has serious interactions with at least 51 different drugs.
  • Moderate interactions of baricitinib include:
    • ifosfamide
    • mechlorethamine
    • trastuzumab

This document does not contain all possible interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist. Check with your physician if you have health questions or concerns.

What Are Warnings and Precautions for Baricitinib?


  • This medication contains baricitinib. Do not take Olumiant if you are allergic to baricitinib or any ingredients contained in this drug.
  • Keep out of reach of children. In case of overdose, get medical help or contact a Poison Control Center immediately.

Black Box Warnings

Serious infections

  • Baricitinib increases the risk for developing serious infections that may lead to hospitalization or death
  • Most patients who developed these infections were taking concomitant immunosuppressants (e.g., methotrexate, corticosteroids)
  • If a serious infection develops, interrupt dosing until the infection is controlled
  • Reported infections include:
    • Active tuberculosis (TB), which may present with pulmonary or extrapulmonary disease; test patients for latent TB before initiating and during therapy; treatment for latent infection should be considered before initiating
    • Invasive fungal infections, including candidiasis and pneumocystosis; patients with invasive fungal infections may present with disseminated, rather than localized, disease
    • Bacterial, viral, and other infections due to opportunistic pathogens
  • Consider risks and benefits before initiating therapy in patients with chronic or recurrent infection
  • Closely monitor for developing signs and symptoms of infection during and after treatment, including the possible development of TB in patients who tested negative for latent TB before initiating baricitinib


  • Lymphoma and other malignancies observed


  • Thrombosis, including deep venous thrombosis (DVT) and pulmonary embolism (PE), was observed at an increased incidence in patients treated with baricitinib compared with placebo
  • Additionally, cases of arterial thrombosis reported
  • Many of these adverse events were serious and some resulted in the death
  • Patients with symptoms of thrombosis should be promptly evaluated


  • None

Effects of Drug Abuse

  • No information is available.

Short-Term Effects

  • See "What Are Side Effects Associated with Using Baricitinib?"

Long-Term Effects

  • See "What Are Side Effects Associated with Using Baricitinib?"


  • Serious and sometimes fatal infections may develop owing to bacterial, mycobacterial, invasive fungal, viral, or other opportunistic pathogens reported; may cause reactivation of latent TB or viral infections
  • Consider risks and benefits before initiating in patients with chronic or recurrent infection, history of serious or opportunistic infection, underlying conditions predisposing them to infection, or patients who have been exposed to tuberculosis or have resided or traveled in areas of endemic tuberculosis or mycoses
  • Consider TB therapy for patients with a negative test for latent TB but who have risk factors for TB infection; consultation with a physician with expertise in TB is recommended to aid in decision about whether initiating anti-TB therapy is appropriate
  • If a new infection develops during treatment, promptly initiate diagnostic tests appropriate for an immunocompromised patient; if necessary, initiate appropriate antimicrobial therapy and closely monitor; interrupt baricitinib therapy if the patient unresponsive to treatment
  • If herpes zoster occurs, interrupt treatment until the episode resolves
  • Malignancies were observed in clinical studies; non-melanoma skin cancers (NMSCs) reported; periodic skin examination is recommended for patients who are at increased risk for skin cancer
  • Perform screening for viral hepatitis by clinical guidelines before starting therapy; unknown impact on chronic viral hepatitis reactivation
  • Increased incidence of thrombosis, including DVT and PE, observed compared with placebo; caution in patients at increased risk of thrombosis
  • Gastrointestinal perforation reported in clinical studies, although the role of JAK inhibition in these events is unknown
  • May increase incidence of neutropenia, lymphopenia, anemia, or elevated LFTs or lipids; monitor laboratory values at baseline and periodically during treatment
  • Prompt investigation of the cause of liver enzyme elevation recommended to identify potential cases of drug-induced liver injury; if increases in ALT or AST are observed and drug-induced liver injury is suspected, interrupt therapy until this diagnosis is excluded

Drug interaction overview

  • Avoid the use of live vaccines; update immunizations in agreement with current immunization guidelines before initiating
  • Coadministration with strong OAT3 inhibitors may increase baricitinib systemic exposure

Pregnancy and Lactation

  • Data on baricitinib use in pregnant women are insufficient to inform a drug-associated risk for major birth defects or miscarriage. In animal embryo-fetal development studies, oral baricitinib administration to pregnant rats and rabbits at exposures equal to and greater than approximately 20 and 84 times the maximum recommended human dose (MRHD), respectively, resulted in reduced fetal body weights, increased embryo lethality (rabbits only), and dose-related increases in skeletal malformations.
  • It is unknown if baricitinib is distributed in human breast milk. Baricitinib is present in the milk of lactating rats. Owing to species-specific differences in lactation physiology, the clinical relevance of these data is not clear. Because of the potential for serious adverse reactions in nursing infants, women are advised not to breastfeed while taking baricitinib.

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