Adverse effects of JAK inhibitors

Paul Moayyedi, MB, is a professor of medicine, assistant dean of research, and director of the Farncombe Family Digestive Health Research Institute in the Faculty of Health Sciences at McMaster University.

What are the adverse effects of Janus kinase (JAK) inhibitors (used in inflammatory bowel disease [IBD] treatment)? How should we monitor patients treated with JAK inhibitors? Which tests should be performed?

The main concern with JAK inhibitors is the risk of thromboembolism. We know from rheumatoid arthritis patients that at higher doses particularly there’s a risk of deep vein thrombosis and possibly pulmonary embolism, which obviously is a serious complication.

There’s no test you could do that could predict who is going to get this complication. These drugs are not recommended for those at high risk of venous thromboembolism. Also, for patients who are taking it, you want to try and use the lowest dose possible. If you have to increase the dose, because, for example, a drug is only partially effective, then you need to be very careful to warn patients of this risk. So that would be the thing I’d highlight most.

The other thing is that all patients should have a varicella zoster vaccination because there is a risk of shingles with this medication.