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Oral JAK Inhibitors

Drug Class: Commonly Known As: Category:
Oral JAK Inhibitors

Oral JAK Inhibitors - Side Effects, Precautions, and Contraindications

What side effects can Oral JAK Inhibitors cause?

Common side effects include: 
  • 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 
Rare but serious side effects include: 

​Side effects
​Warning signs
​Allergic reaction
  • ​rash 
  • swollen face/eyes/ lips/tongue 
  • difficulty breathing
​Infection
  • ​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
  • ​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


If you experience any of these symptoms, you should stop your medication and see your healthcare professional immediately.

Before taking Oral JAK Inhibitors , what precautions must I follow?

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 food or medicine must I avoid when I take Oral JAK Inhibitors ?

  • 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.

Oral JAK Inhibitors - Additional Information

  • Updated on 10/31/2022 12:00:00 AM
  • Article contributed by PSS National Medication Information Workgroup PSS National Medication Information Workgroup
The information provided is not intended as medical advice. Terms of use. Information provided by SingHealth

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