Prescription medication · JAK Inhibitor
tofacitinib
Also sold as Xeljanz. Xeljanz treats rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis and ulcerative colitis in adults.
Data updated 2026-05-15
- 181,998
- FDA reportsHeavily reported
- 5
- InteractionsFew interactions
- $93.73
- Brand price (NADAC)
What the data shows
tofacitinib (Xeljanz) is a prescription JAK Inhibitor, more reported than roughly 9 in 10 tracked drugs (181,998 FDA reports), with 5 documented drug interactions.
Reporting volume reflects how widely a drug is used and studied, not how dangerous it is, a FAERS report documents a temporal association, never proof of cause.
tofacitinib (Xeljanz) is a prescription JAK Inhibitor. Xeljanz treats rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis and ulcerative colitis in adults.
Xeljanz is a medicine that reduces inflammation in your body. It is used to treat conditions like arthritis and ulcerative colitis.
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Drug Pricing (NADAC)
Brand Price
$93.73/unit
Generic Available
No
PF PRISM CV
Pricing data from NADAC (CMS), effective December 18, 2024. Compare all drug costs →
What it does
Xeljanz treats rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis and ulcerative colitis in adults.
Common side effects
Upper respiratory tract infection (like a cold), Runny nose, Diarrhea
Key warnings
Xeljanz can increase your risk of serious infections, which could lead to hospitalization or death.
The sections below are summarized in plain English from tofacitinib's FDA-approved prescribing information. They describe what the official label says, and are not personal medical advice.
How It Works
Xeljanz is a JAK inhibitor. It works by blocking certain enzymes in your body. These enzymes cause inflammation, so blocking them helps to reduce swelling and pain.
How to Take It
Take Xeljanz exactly as your doctor tells you. For rheumatoid arthritis, psoriatic arthritis, or ankylosing spondylitis, the usual dose is 5 mg twice a day or 11 mg once a day. For ulcerative colitis, you may start at 10 mg twice a day or 22 mg once a day, then lower the dose. You can take Xeljanz with or without food.
This is a plain-language summary of tofacitinib's FDA labeling, not individualized dosing advice. Ask a pharmacist or prescriber before changing how you take this medication.
Pregnancy & Breastfeeding
It is not known if Xeljanz will harm your unborn baby. Talk to your doctor if you are pregnant or plan to become pregnant. You should not breastfeed while taking Xeljanz.
This is a plain-language summary of tofacitinib's FDA labeling, not individualized advice. Ask a pharmacist or prescriber about pregnancy or breastfeeding on this medication.
Missed Dose
If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and continue with your regular schedule.
This is a plain-language summary of tofacitinib's FDA labeling, not individualized advice. Ask a pharmacist or prescriber what to do about your specific missed dose.
Storage
Store Xeljanz tablets and oral solution at room temperature, away from light and moisture.
Side Effects (from patient reports)
Based on 181,998 FDA adverse event reports.
Most-reported reactions
Adverse reactions in FAERS for tofacitinib, by number of reports
- Pain
Pain
25,737 reports
- Joint pain
Joint pain
19,670 reports
- Condition got worse
Condition got worse
19,467 reports
- Rheumatoid arthritis
Rheumatoid arthritis
18,797 reports
- Tiredness
Tiredness
16,595 reports
- Swollen joint
Swollen joint
14,455 reports
- Headache
Headache
13,405 reports
- Rash
Rash
11,912 reports
- Feeling unwell
Feeling unwell
10,489 reports
- Pain in arm or leg 10,277
Pain in arm or leg
10,277 reports
What this shows Bars show how often each reaction was reported, not how likely it is to happen, a report records a temporal association, never proof that the drug caused it.
Reports over time
Adverse-event reports filed for tofacitinib each year to the FDA Adverse Event Reporting System (FAERS).
Year-to-year volume tracks usage, prescribing, and scrutiny, not a change in per-patient risk. Source: FDA FAERS.
Where tofacitinib sits
tofacitinib has more FDA adverse-event reports than 94% of the drugs FAERS tracks. A high position reflects how widely a drug is used and watched, not how dangerous it is.
Percentile across all drugs PlainMeds tracks by FAERS report volume. The dot is tofacitinib; the line is the median (50th percentile).
FDA Adverse Event Report Analysis
Detailed analysis of 181,998 reports from the FDA Adverse Event Reporting System (FAERS). Reports span 2008–2025.
Total Reports
181,998
Reports Mentioning Death
8,655
4.8% of reports — not proof of cause
Hospitalization Reports
24,557
Top Indication
Rheumatoid Arthritis
Gender Distribution
Age Distribution
Most Reported Adverse Reactions (FAERS)
| # | Reaction | Reports |
|---|---|---|
| 2 | PAIN | 25,737 |
| 3 | ARTHRALGIA | 19,670 |
| 4 | CONDITION AGGRAVATED | 19,467 |
| 5 | RHEUMATOID ARTHRITIS | 18,797 |
| 6 | FATIGUE | 16,595 |
| 8 | JOINT SWELLING | 14,455 |
| 9 | HEADACHE | 13,405 |
| 10 | RASH | 11,912 |
| 12 | MALAISE | 10,489 |
| 13 | PAIN IN EXTREMITY | 10,277 |
| 14 | ABDOMINAL DISCOMFORT | 10,168 |
| 15 | NAUSEA | 9,949 |
| 16 | DIARRHOEA | 9,695 |
| 17 | PERIPHERAL SWELLING | 9,668 |
| 18 | ALOPECIA | 9,255 |
Reactions in Death Reports
Reactions in Hospitalization Reports
Source: FDA FAERS (Adverse Event Reporting System) FDA FAERS (Adverse Event Reporting System) Reports are voluntary and do not establish causation
Serious Warnings
Xeljanz can increase your risk of serious infections, which could lead to hospitalization or death. It may also increase your risk of blood clots, cancer, and heart problems. Talk to your doctor about these risks before taking Xeljanz.
Known Drug Interactions
Table 7: Clinically Significant Interactions Affecting XELJANZ/XELJANZ XR When Concomitantly Used with Other Drugs Strong CYP3A4 Inhibitors (e.g., ketoconazole) Clinical Impact Increased exposure to tofacitinib Intervention Dosage modification of XELJANZ/XELJANZ XR is recommended [see Dosage and Administration (2) , Clinical Pharmacology, Figure 3 (12.3) ] Moderate CYP3A4 Inhibitors Concomitantly Used with Strong CYP2C19 Inhibitors (e.g., fluconazole) Clinical Impact Increased exposure to tofacitinib Intervention Dosage modification of XELJANZ/XELJANZ XR is recommended [see Dosage and...
Mechanism: Ketoconazole blocks the enzymes that break down tofacitinib, which can cause the drug to build up to high levels in your body.
What to do: Your doctor will likely reduce your dose of tofacitinib to prevent side effects from high drug levels.
Table 7: Clinically Significant Interactions Affecting XELJANZ/XELJANZ XR When Concomitantly Used with Other Drugs Strong CYP3A4 Inhibitors (e.g., ketoconazole) Clinical Impact Increased exposure to tofacitinib Intervention Dosage modification of XELJANZ/XELJANZ XR is recommended [see Dosage and Administration (2) , Clinical Pharmacology, Figure 3 (12.3) ] Moderate CYP3A4 Inhibitors Concomitantly Used with Strong CYP2C19 Inhibitors (e.g., fluconazole) Clinical Impact Increased exposure to tofacitinib Intervention Dosage modification of XELJANZ/XELJANZ XR is recommended [see Dosage and...
Mechanism: Using these two drugs together can overly weaken your immune system, making it harder for your body to fight off infections.
What to do: This combination is generally not recommended, and you should talk to your doctor about safer alternatives.
Table 7: Clinically Significant Interactions Affecting XELJANZ/XELJANZ XR When Concomitantly Used with Other Drugs Strong CYP3A4 Inhibitors (e.g., ketoconazole) Clinical Impact Increased exposure to tofacitinib Intervention Dosage modification of XELJANZ/XELJANZ XR is recommended [see Dosage and Administration (2) , Clinical Pharmacology, Figure 3 (12.3) ] Moderate CYP3A4 Inhibitors Concomitantly Used with Strong CYP2C19 Inhibitors (e.g., fluconazole) Clinical Impact Increased exposure to tofacitinib Intervention Dosage modification of XELJANZ/XELJANZ XR is recommended [see Dosage and...
Mechanism: Rifampin causes your body to process tofacitinib much faster than normal, which can lower the amount of medicine in your blood.
What to do: Your doctor may need to monitor your condition closely as tofacitinib may be less effective during this time.
) Tofacitinib: Coadministration of fluconazole (400 mg on Day 1 and 200 mg once daily for 6 days [Days 2 to 7]) and tofacitinib (30 mg single dose on Day 5) in healthy subjects resulted in increased mean tofacitinib AUC and C max values of approximately 79% (90% CI: 64% to 96%) and 27% (90% CI: 12% to 44%), respectively, compared to administration of tofacitinib alone. (See CLINICAL PHARMACOLOGY: Drug Interaction Studies .) Tofacitinib: Systemic exposure to tofacitinib is increased when tofacitinib is coadministered with fluconazole. Reduce the dose of tofacitinib when given concomitantly...
Mechanism: Fluconazole increases the amount of tofacitinib in your system by slowing its metabolism. This can lead to a higher risk of side effects from the tofacitinib.
What to do: Your doctor should reduce your dose of tofacitinib when it is taken at the same time as fluconazole. Follow your healthcare provider's instructions for the specific dosage change.
Janus kinase (JAK) inhibitors tofacitinib ↑ tofacitinib Dosage adjustment of tofacitinib is recommended. Refer to the tofacitinib product label for more information.
Mechanism: This medicine blocks the enzymes that usually break down tofacitinib, causing more of it to stay in your body.
What to do: Your doctor will likely need to change your dose of tofacitinib while you are on this treatment.
This is a plain-language summary of interactions documented in FDA labeling, not individualized advice. Ask a pharmacist or prescriber before combining medications.
Common Questions
Can I take Xeljanz with other medicines?
How long does it take for Xeljanz to work?
What should I do if I get an infection while taking Xeljanz?
Can Xeljanz cause cancer?
Can Xeljanz cause blood clots?
Will Xeljanz cure my condition?
Can I get vaccines while taking Xeljanz?
What tests will I need while taking Xeljanz?
Can I drink alcohol while taking Xeljanz?
What if Xeljanz does not seem to be working?
What are the common side effects of tofacitinib?
Does tofacitinib interact with other medications?
What drug class is tofacitinib?
Is tofacitinib safe during pregnancy?
Related Medications in JAK Inhibitor
Other drugs grouped near tofacitinib - same-class peers and common alternatives.
abatacept
Orencia
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acetaminophen
Tylenol
Acetaminophen (Tylenol) is a medicine that can relieve pain and reduce fever.
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acetaminophen/hydrocodone
Vicodin, Norco
This medicine contains acetaminophen and hydrocodone.
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acetaminophen/oxycodone
Percocet
Percocet is a strong pain medicine.
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adalimumab
Humira
Idacio is a medicine that blocks a protein called TNF.
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Medication Guides
Understanding Drug Interactions
How CYP450 enzymes, inhibitors, and inducers affect your medications
Generic vs Brand Name Drugs
FDA requirements, cost savings, and when the difference matters
Narrow Therapeutic Index Drugs
Why some drugs demand precise dosing and monitoring
Common Drug Interactions
Dangerous medication combinations and how to protect yourself
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What the FDA Data Shows for tofacitinib
The FDA label for tofacitinib (sold under brand names such as Xeljanz) classifies it as a prescription-only medication in the JAK Inhibitor class. Xeljanz treats rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis and ulcerative colitis in adults. Official labeling lists 8 commonly reported side effects, including Upper respiratory tract infection (like a cold), Runny nose, Diarrhea.
Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 181,998 voluntary reports. The database also lists 5 documented drug interactions derived from FDA labeling, with the top-flagged interaction rated minor severity. NADAC pricing from CMS.
Report counts do not establish causation, a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history, and patent information further shape supply and switching decisions. This page summarizes public FDA data for educational purposes only and is not a substitute for professional medical advice, always consult a licensed healthcare provider before starting, stopping, or changing any medication.
Data Sources
Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS). Pricing: CMS National Average Drug Acquisition Cost (NADAC).
FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. Always consult a healthcare professional before making medication decisions.
Last updated: January 30, 2026
Read our methodology - how this data is sourced, computed, and verified.
Data currency: FDA FAERS adverse-event reports through 2025, CMS NADAC acquisition-cost pricing effective December 2024, compiled and last refreshed May 2026. See our methodology for per-source dates and refresh cadence. Spot a figure that looks wrong? Report a correction.
All federal data sources used on this page
- FDA Orange Book - approved drug products with therapeutic equivalence. accessdata.fda.gov/cder/ob
- FDA DailyMed - NIH-hosted drug labeling for FDA-approved meds. dailymed.nlm.nih.gov
- FDA Adverse Event Reporting System (FAERS) - post-marketing safety surveillance. fda.gov/drugs/faers
- NLM RxNorm - standardized clinical drug nomenclature. nlm.nih.gov/research/umls/rxnorm
- CMS Medicare Part B Drug Average Sales Price Files - federal drug pricing data. cms.gov/medicare/part-b-drugs/asp
- FDA Drug Shortages Database - current and resolved drug shortage tracking. accessdata.fda.gov/drugshortages