Oral JAK Inhibitors

Medication Information Leaflet

What is this medication for?

​Oral JAK Inhibitors
​Atopic eczema
​Baricitinib​Atopic eczema, rheumatoid arthritis
​Rheumatoid arthritis, psoriatic arthritis and ulcerative colitis
Upadacitinib​​Atopic eczema, rheumatoid arthritis, psoriatic arthritis and ankylosing spondylitis
This group of medications can also be used for other conditions, including the management of certain hair conditions.

How should I take/use this medication?

  • This medication may be taken with or without food. 
  • You may take the medication with food if you have nausea/vomiting or stomach upset.
  • This medication has to be taken regularly to obtain the full benefits of the medication. It may take weeks to months for an effect to be seen.

What should I do if I forget to take/use this medication?

Take the missed dose as soon as you remember. If it is almost time for the next dose, skip the missed dose. Do not double the next dose to make up for the missed dose.

What precautions should I take?

  • Inform your healthcare professional if: 
    • You have severe infections (e.g., tuberculosis, shingles, fungal or bacterial or viral infections) or have immune system problems
    • You have stomach problems or intestinal disease
    • You have kidney problems
    • You have liver problems
    • You have lung problems
    • You have personal or family history of heart problems, high blood pressure, stroke and/or blood clots
    • You have any personal or family history of cancer
    • You are pregnant or planning to become pregnant
    • You are breast-feeding
    • You are a current or past smoker
    • You have any allergies
    • You have been given Abrocitinib but have lactose allergy, galactose intolerance, total lactase deficiency or glucose-galactose malabsorption. (Abrocitinib contains lactose)
  • Blood tests and other tests will be done before and while on this medication to decide if it is suitable for you, as well as to monitor for side effects.
  • Do not allow anyone else to take this medication.

What are some common side-effects of this medication?

If any of the following side effects persist or are severe, you should consult your doctor.
  • Symptoms of a common cold (blocked nose, runny nose, sneezing, sore throat, coughing, mild fever (below 38°C)
  • Blister-like rashes, shingles
    • See a doctor immediately.
  • Nausea/vomiting, stomach upset, diarrhea
  • Increase in cholesterol levels and amount of triglycerides (fats) in your blood
  • Acne
  • Headache
  • Abrocitinib: Dizziness

What are some rare but serious side-effects that I need to seek medical advice immediately?

If you experience any of these symptoms, you should stop your medication and see your healthcare professional immediately.
​Side effects
Warning signs
​Allergic reaction
  • rash
  • swollen face/eyes/lips/tongue 
  • difficulty breathing

  • ​burning sensation/pain on urination 
  • fever more than 38°C
  • chills
  • feeling very tired
  • persistent cough
  • very bad sore throat
  • wounds that will not heal
  • mouth sores
​Increase in muscle enzymes
  • ​dark urine
  • muscle pain
​Liver problems
  • ​dark urine
  • feeling very tired
  • lack of appetite
  • persistent abdominal pain
  • light-colored stool
  • yellow skin or eyes
​Stomach problems
(applicable to Baricitinib, Tofacitinib and Upadacitinib only)
  • severe stomach pain
  • blood in the stool
  • change in bowel habits
​Heart problems, stroke, blood clots
  • ​breathlessness
  • chest pain or tightness
  • unusual pain or discomfort in your arms, back, neck, jaw or stomach
  • weakness in 1 part or side of your body
  • slurred speech
  • drooping on 1 side of your mouth
  • red, painful or swollen leg or arm
  • Abrocitinib: symptoms of high blood pressure (severe headache, change in eyesight, passing out)
Blood disorders
  • ​low red blood cell count
  • low white blood cell count
  • transient low platelet count e.g., unusual bleeding or bruising (Abrocitinib)
​Cancer or malignancy
  • ​change in color or size of a mole
  • a skin lump or growth
  • unexplained weight loss
  • loss of appetite

What food or medication should I avoid when I take this medication?

  • Inform your doctor if you are taking any other medications (especially blood thinners e.g., aspirin (>81mg/day) during the first 3 months of Abrocitinib), over-the-counter medications, including vitamin and mineral supplements, and herbal products.
  • Consult your doctor or pharmacist before immunizations (vaccinations) as this medication may either raise the chance of an infection or reduce the effectiveness of the vaccine. 
  • Avoid crowded places and consumption of raw or undercooked food (e.g., half-boiled eggs) while on this medication as it may reduce the ability of your body to fight against infection.

How should I store this medication?

Store in a cool and dry place, away from direct sunlight. Keep this medication away from children. 

How should I throw away this medication safely?

Pack this medication into a black trash bag and seal it tightly before throwing it into the rubbish chute or bin. 

If you take more than the recommended dose, please seek medical advice immediately. The information provided on this page does not replace information from your healthcare professional. Please consult your healthcare professional for more information.

This article is jointly developed by members of the National Medication Information workgroup. The workgroup consists of cluster partners (National Healthcare Group, National University Health System and SingHealth), community pharmacies (Guardian, Unity and Watsons) and Pharmaceutical Society of Singapore. The content does not reflect drug availability and supply information in pharmacies and healthcare institutions. You are advised to check with the respective institutions for such information.

Last updated on Oct 2022
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