Drug class · FAERS comparison

Janus Kinase Inhibitor side effects compared: 4 drugs, 94,682 FDA adverse event reports

Class as assigned in the FDA label (Established Pharmacologic Class) · data 2026-09-14

How to read this page. Report counts are not incidence rates: a drug with more reports is usually older, more widely used or more publicised, not more dangerous. Signals are screened against each product's FDA label on its own page; a term flagged across most of a class usually reflects the shared mechanism or the shared patient population.

Members

Drug	FAERS reports	Serious	Death outcome	Boxed warning	Top labeled signals	Unlabeled (unassessed)
Upadacitinib (Rinvoq)	81,026	68%	3,016	boxed	Ileostomy; Eczema herpeticum; Small intestinal resection	Knee arthroplasty; Colectomy
Baricitinib (Olumiant)	9,584	69%	877	boxed	Covid-19 pneumonia; Thrombocytosis; Diverticulitis intestinal perforated	Haemophagocytic lymphohistiocytosis; Bronchopulmonary aspergillosis
Abrocitinib (Cibinqo)	3,839	34%	65	boxed	Acne; Dry skin; Herpes zoster	Pruritus; Eczema
Delgocitinib (Anzupgo)	233	33%	2	–	–	Dermatitis atopic; Dermatitis

Class-wide signals (flagged in at least 2 of 4 members)

Reaction	Members flagged	Median PRR	Reports (sum)	In label
Eczema herpeticum	2/4	61.0	96	2/2 members' labels
Dermatitis	2/4	45.7	37	0/2 members' labels
Dermatitis atopic	2/4	31.9	196	0/2 members' labels
Arthrodesis	2/4	20.3	73	0/2 members' labels

Member-specific signals (flagged in exactly one drug)

Reaction	Drug	Reports	PRR	Label screen
Ostomy bag placement	Upadacitinib	130	112.5	Not in label — unassessed
Semen discolouration	Upadacitinib	81	94.9	Not in label — unassessed
Subcutaneous drug absorption impaired	Upadacitinib	105	61.7	Not in label — unassessed
Stoma creation	Upadacitinib	125	59.0	Not in label — unassessed
Intestinal anastomosis	Upadacitinib	81	38.2	Not in label — unassessed
Ileostomy	Upadacitinib	288	33.2	Labeled adverse reaction
Medical device implantation	Upadacitinib	150	28.3	Not in label — unassessed
Colectomy total	Upadacitinib	54	27.6	Not in label — unassessed
Shoulder arthroplasty	Upadacitinib	251	27.0	Not in label — unassessed
Neck surgery	Upadacitinib	171	20.7	Not in label — unassessed
Haemophagocytic lymphohistiocytosis	Baricitinib	62	18.9	Not in label — unassessed
Colectomy	Upadacitinib	383	18.9	Not in label — unassessed
Wrist surgery	Upadacitinib	63	18.9	Not in label — unassessed
Knee arthroplasty	Upadacitinib	1,409	18.7	Not in label — unassessed
Covid-19 pneumonia	Baricitinib	96	17.8	Labeled adverse reaction
Joint arthroplasty	Upadacitinib	114	17.5	Not in label — unassessed
Hip surgery	Upadacitinib	314	16.2	Not in label — unassessed
Small intestinal resection	Upadacitinib	66	15.6	Labeled (related wording)
Bronchopulmonary aspergillosis	Baricitinib	54	15.4	Not in label — unassessed
Spinal fusion surgery	Upadacitinib	224	15.2	Not in label — unassessed
Oral surgery	Upadacitinib	127	14.9	Not in label — unassessed
Eczema	Abrocitinib	91	9.9	Not in label — unassessed
Acne	Abrocitinib	88	6.3	Labeled adverse reaction
Herpes zoster	Abrocitinib	53	5.0	Labeled — boxed warning
Sleep disorder	Abrocitinib	55	4.3	Not in label — unassessed

Common questions

Which janus kinase inhibitor has the most FDA adverse event reports?

Upadacitinib has the most FAERS co-reports in this class (81,026), followed by Baricitinib (9,584). Report volume tracks how widely and how long a drug has been used, and how much attention it has had, far more than its risk.

Which side effects are shared across janus kinase inhibitor drugs?

Reaction terms flagged in at least half of the 4 members include eczema herpeticum, dermatitis, dermatitis atopic, arthrodesis. A term shared across a class usually reflects the shared mechanism (or the shared patient population) rather than one product.

Does a FAERS signal mean the drug causes the reaction?

No. These are disproportionality signals from voluntary reports with no denominator. Each is screened against the FDA label (known vs unlabeled) on the drug pages; causality needs temporality, dose-response, plausibility and trial or cohort evidence.

Sources: openFDA FAERS pair statistics (OpenPV build 2026-09-14), FDA labels via openFDA, seriousness and death counts from openFDA count queries. Generated 2026-10-08. Not medical advice.