Upadacitinib

• Rheumatoid Arthritis
• Psoriatic Arthritis
• Ulcerative Colitis
• Atopic Dermatitis
• Crohn's Disease

Upadacitinib (Rinvoq) is an oral selective Janus kinase 1 inhibitor used to treat moderate-to-severe rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, ulcerative colitis, Crohn's disease, and atopic dermatitis in patients age 12 and older. As an oral once-daily extended-release tablet, it offers an alternative to injectable biologic therapy for several conditions where chronic immune-mediated inflammation drives disease activity. The boxed-warning safety profile shapes patient selection and monitoring more than dosing complexity does, and shared decision-making is essential before initiation.

Mechanism of Action

The Janus kinase family — JAK1, JAK2, JAK3, and TYK2 — pairs with cell-surface cytokine receptors to transmit signals from circulating cytokines into the cell, ultimately activating STAT transcription factors that change gene expression. Many of the cytokines central to autoimmune inflammation, including IL-6, interferon-gamma, IL-7, IL-15, IL-21, and IL-22, signal through JAK1-containing receptor complexes. Upadacitinib preferentially inhibits JAK1 over JAK2 and JAK3 in cellular assays. By blocking JAK1 the drug interrupts these inflammatory signals, reducing synovial inflammation in joints, epidermal inflammation in atopic dermatitis, and mucosal inflammation in inflammatory bowel disease.

The selectivity for JAK1 is intended to spare JAK2-mediated signaling for erythropoietin and thrombopoietin, theoretically reducing anemia and thrombocytopenia compared with less selective JAK inhibitors, although in practice both remain class-level concerns. Because JAK signaling also supports normal immune surveillance and host defense, JAK inhibition predictably increases susceptibility to viral infections such as herpes zoster, opportunistic infections, and reactivation of latent tuberculosis or hepatitis B. Lipid panels typically rise within weeks of starting therapy, an on-target effect related to interferon signaling that does not necessarily require lipid-lowering treatment but should be monitored. The drug is metabolized predominantly by CYP3A4, so strong inhibitors and inducers of that enzyme can shift exposure substantially. Onset of clinical benefit varies by indication: skin and joint symptoms often improve within two to four weeks, while gastrointestinal mucosal healing takes longer. Background on biologic and small-molecule therapy from the American College of Rheumatology is useful for patients new to this drug class.

Clinical Use

Within rheumatoid arthritis, current guidelines from the American College of Rheumatology recommend methotrexate as initial therapy. When patients have inadequate response or intolerance to methotrexate, the next step is either a biologic — typically a TNF inhibitor such as adalimumab or etanercept — or a JAK inhibitor like upadacitinib. The ORAL Surveillance trial raised safety signals for the JAK class regarding cardiovascular events and malignancy in older patients with cardiovascular risk factors, leading the FDA to limit JAK inhibitor use to patients with inadequate response to one or more TNF inhibitors. The same positioning applies to psoriatic arthritis and inflammatory bowel disease.

For atopic dermatitis it is typically used after topical therapy and other systemic options including dupilumab have failed or are inappropriate. Patient selection considers age, cardiovascular and venous thromboembolism risk, malignancy history, smoking status, and infection history. Compared with biologics, upadacitinib offers oral dosing, faster onset (often within two to four weeks for skin and joint symptoms), and the convenience of stopping and restarting therapy without rebuilding antibody titers. The trade-offs are the boxed warnings, daily lab monitoring requirements early on, and the need for vaccination updates before starting. Comparative effectiveness data show JAK inhibitors achieve clinical response in 50 to 70 percent of patients across indications, broadly similar to biologics but with different side-effect profiles. The American Academy of Dermatology atopic dermatitis page is helpful patient reading. For inflammatory bowel disease, the convenience of oral therapy and the option of dose adjustment between 15 and 30 mg make upadacitinib attractive, particularly for patients who failed multiple biologics or who prefer to avoid injections.

How to Take It

Upadacitinib is taken once daily as an extended-release tablet, with or without food. The tablet must be swallowed whole — it cannot be split, crushed, or chewed because that would disrupt the extended-release matrix. Doses range from 15 to 45 mg depending on the indication and phase of treatment. Missed doses should be taken as soon as remembered the same day; if it is the next day, the missed dose is skipped. Tablets are stored at room temperature in the original container, protected from moisture. The first two weeks may bring upper respiratory symptoms, mild nausea, headache, or a small acne flare. Symptom improvement in joint disease is often noticeable within two weeks and meaningful by four weeks; skin and gastrointestinal responses follow similar timelines. Patients should not start upadacitinib if they have an active infection, and should hold doses temporarily for serious infections, surgery requiring hospitalization, or pregnancy. Patients are advised to wash hands and avoid contact with people known to have active varicella, herpes zoster, or other transmissible viral illnesses given their increased susceptibility.

Monitoring and Follow-Up

Before starting, screening includes tuberculosis testing (interferon-gamma release assay or PPD), hepatitis B and C serology, complete blood count, comprehensive metabolic panel, lipid panel, and review of vaccination status — particularly herpes zoster (Shingrix) and pneumococcal vaccines, which should be administered before initiation when possible because live vaccines cannot be given during therapy. After starting, complete blood count and liver function are checked at four to eight weeks and then at three to six month intervals. Lipid panel is rechecked at twelve weeks and managed with diet or statin therapy if persistently elevated. Treatment is not initiated when lymphocyte count is below 500, absolute neutrophil count below 1000, or hemoglobin below 8 g/dL, and is held if these thresholds are crossed during therapy. ALT or AST elevations greater than five times the upper limit of normal warrant interruption. Disease activity is assessed at every visit using condition-specific tools — DAS28 or CDAI for rheumatoid arthritis, Mayo score for ulcerative colitis, EASI or vIGA for atopic dermatitis. Annual age-appropriate cancer screening including skin examination remains important given the malignancy signal. Background on TB screening from the CDC supports the screening conversation.

Special Populations

Upadacitinib carries class boxed warnings for serious infection, mortality in older RA patients with cardiovascular risk factors, malignancy including lymphoma and skin cancer, major adverse cardiovascular events, and thrombosis. These warnings shape its use in older adults — patients over 65 are typically considered for it only when other options have failed, and 15 mg is preferred for atopic dermatitis at any age. Pregnancy is contraindicated based on animal teratogenicity, and effective contraception is required during therapy and for four weeks after the last dose; women planning pregnancy should transition to a safer agent. Breastfeeding is not recommended. Pediatric use is limited to atopic dermatitis in patients 12 and older weighing at least 40 kg. Severe hepatic impairment is a contraindication. Mild to moderate renal or hepatic impairment requires no dose change for most indications, but severe renal impairment warrants caution. Smokers and patients with prior malignancy require careful risk discussion before initiation. Strong CYP3A4 inhibitors such as ketoconazole and clarithromycin can raise upadacitinib levels and may require dose reduction; strong CYP3A4 inducers such as rifampin reduce efficacy and are usually avoided. Live vaccines are contraindicated during therapy, so vaccination planning must precede initiation by several weeks ideally.

When to Contact Your Doctor

Call promptly for fever, persistent cough, painful urination, severe sore throat, or any concern for serious infection — JAK inhibitor users have increased risk of opportunistic and reactivation infections. New shortness of breath, leg swelling or pain, chest pain, or sudden severe headache may indicate venous or arterial thrombosis. New skin lesions that change rapidly, bleed, or do not heal warrant evaluation for skin cancer. Persistent abdominal pain, especially with fever, may signal GI perforation. Yellowing of the skin or eyes, dark urine, or right upper quadrant pain suggest liver involvement. A herpes zoster rash deserves prompt antiviral therapy. Pregnancy or planned pregnancy should be discussed before the next dose. Severe muscle pain or weakness with dark urine could indicate rare myopathy and warrants urgent labs.

For coordinated care of inflammatory arthritis, inflammatory bowel disease, atopic dermatitis, or any complex immunologic condition, contact us or schedule a visit with our St. Petersburg internal medicine team for collaborative management.