FDA Adverse Events Reports (FAERS) Summary for LITFULO

These tables and charts are based on 1,629 total reports for LITFULO (RITLECITINIB TOSYLATE) received by the FDA Adverse Event Reporting System (FAERS) from 2004 through April 28, 2026.

This FAERS total includes 1,607 pharmaceutical company-submitted and non-U.S. FAERS reports and 22 U.S. consumer or healthcare provider-submitted MedWatch reports. For a separate summary of the 22 U.S. reports filed via the FDA MedWatch voluntary reporting system, view our FDA MedWatch LITFULO summary report. (See notes section below for explanation of FDA’s mandatory and voluntary reporting system.)

Top 20 Adverse Effects Associated with LITFULO (reported in FAERS Database)

	Side Effect	# of FDA Reports
1	DRUG INEFFECTIVE	296
2	DRUG EFFECT INCOMPLETE	125
3	CONDITION AGGRAVATED	104
4	OFF LABEL USE	89
5	HEADACHE	75
6	DIARRHEA	56
7	HAIR LOSS	52
8	PRODUCT DOSE OMISSION ISSUE	50
9	ITCHING	45
10	HIVES	45
11	ACNE	41
12	FATIGUE	37
13	RASH	37
14	NAUSEA	33
15	BLOOD CREATINE PHOSPHOKINASE INCREASED	32
16	DIZZINESS	31
17	ALOPECIA AREATA	27
18	ILLNESS	27
19	THERAPEUTIC PRODUCT EFFECT DECREASED	24
20	INFECTION	23
21	COMMON COLD	23
22	DRUG HYPERSENSITIVITY	22
23	ANXIETY	20
24	COVID-19	20
25	VOMITING	18
26	WEIGHT INCREASED	18
27	ELEVATED LIVER ENZYMES	17
28	JOINT PAIN	16
29	CHEST PAIN	16
30	HYPERSENSITIVITY	16
31	PAIN IN EXTREMITY	16
32	BRUISE	15
33	ABDOMINAL DISCOMFORT	14
34	MALAISE	14
35	COUGH	13
36	DRUG INEFFECTIVE FOR UNAPPROVED INDICATION	13
37	INTENTIONAL PRODUCT MISUSE	13
38	DRUG EFFECT INCREASED	13
39	SHORTNESS OF BREATH	12
40	MIGRAINE	12
41	PRODUCT PRESCRIBING ERROR	12
42	PRODUCT USE ISSUE	12
43	ABDOMINAL PAIN UPPER	11
44	BLOOD CHOLESTEROL INCREASED	11
45	DEPRESSION	11
46	MUSCLE SPASMS	11
47	PALPITATIONS	11
48	FEVER	11
49	DROWSINESS	11
50	WHITE BLOOD CELL COUNT DECREASED	11
51	ECZEMA	10
52	ELEVATED LIVER ENZYMES	10
53	MUSCLE PAIN	10
54	PAIN	10
55	SINUSITIS	10
56	URINARY TRACT INFECTION	10
57	ABDOMINAL PAIN	9
58	DRUG INTERACTION	9
59	GASTROINTESTINAL DISORDER	9
60	LOSS OF PERSONAL INDEPENDENCE IN DAILY ACTIVITIES	9
61	ALT LIVER ENZYME INCREASED	8
62	LACK OF STRENGTH AND ENERGY (ASTHENIA)	8
63	ASTHMA	8
64	BACK PAIN	8
65	BLOOD TRIGLYCERIDES INCREASED	8
66	DIABETES MELLITUS	8
67	DISEASE RECURRENCE	8
68	HAIR COLOUR CHANGES	8
69	INSOMNIA	8
70	PLATELET COUNT DECREASED	8
71	QUALITY OF LIFE DECREASED	8
72	STRESS	8
73	ASPARTATE AMINOTRANSFERASE INCREASED	7
74	DERMATITIS	7
75	FEELING ABNORMAL	7
76	IMPAIRED QUALITY OF LIFE	7
77	INFLUENZA	7
78	LIPIDS INCREASED	7
79	TUBERCULOSIS	7
80	ABDOMINAL DISTENSION	6
81	BLOOD PRESSURE INCREASED	6
82	DRUG EFFECTIVE FOR UNAPPROVED INDICATION	6
83	EMOTIONAL DISTRESS	6
84	HEPATITIS B SURFACE ANTIBODY POSITIVE	6
85	SHINGLES	6
86	EXCESS SWEATING	6
87	HIGH BLOOD PRESSURE	6
88	NUMBNESS	6
89	INTENTIONAL DOSE OMISSION	6
90	LYMPHOPENIA	6
91	LOSS OF EYELASH OR EYEBROW HAIR	6
92	SKIN DISORDER	6
93	SKIN IRRITATION	6
94	UPPER RESPIRATORY TRACT INFECTION	6
95	WEIGHT DECREASED	6
96	BLOOD PRESSURE ABNORMAL	5
97	CHEST DISCOMFORT	5
98	ECZEMA	5
99	SKIN REDNESS	5
100	INFLAMMATION OF HAIR FOLLICLES	5

Latest Known Outcomes for Reactions Reported for LITFULO

	Latest Known Outcome for Reported Reactions	Number of Cases
1	Unknown Outcome	1312
2	Patient has not recovered/symtoms have not resolved	167
3	Patient recovered	165
4	Patient is recovering/symptoms resolving	84
5	Patient has recovered but has consequent health issues	2
6	Patient died	1

Search all MedWatch and FAERS by keyword:

LITFULO Total Reports

Male	Female	Unknown	Total
501	960		1,629

Top Countries Reporting

	Country	Number of Reports
1	United States	1542
2	Japan	29
3	United Kingdom	23
4	EU	15
5	China	5
6	Puerto Rico	4
7	Czech Republic	3
8	Brazil	2
9	Israel	2
10	Taiwan	2

Outcomes for Reports

Serious: 268
Not Serious: 1361
Note: A serious outcome means the adverse event resulted in death, a life threatening condition, hospitalization, disability, congenital anomaly, or other serious condition.

Top Indications

Alopecia areata
HAIR LOSS
Alopecia universalis
Alopecia totalis
Lichen planopilaris

Top Companies Reporting

PFIZER

Safety-Related FDA Updates

LITFULO (ritlecitinib) Rx Drug:
Risk of low blood sugar (hypoglycemia) in patients with diabetes Safety-related Labeling Changes

Have experience (good or bad) with LITFULO? Rate LITFULO at Ask a Patient.

For serious adverse events, report them to the FDA by contacting the drug manufacturer or report directly through the MedWatch voluntary reporting form.

Notes

This report, created by AskaPatient.com, is derived from the cases for LITFULO reported to the United States Food and Drug Administration (FDA) FDA Safety Information and Adverse Event Reporting System (FAERS) and obtained from Open FDA. Data was last updated with reports received through April 28, 2026.

This summary includes ALL reports where the drug is a "primary OR secondary OR suspected interacting" drug. Typically, reports are filed for the most serious type or "event" and do not represent incidental or minor side effects. The majority of these reports are mandatory reports submitted by pharmaceutical companies, who receive complaints from consumers. The reactions, side effects, or "adverse events," represent up to the 20 most frequently occuring events in the database for a drug related to the event. This report also features counts of latest known outcomes associated with reported side effects, but does not provide the specific outcomes for specific adverse events.

Adverse Event Reports are submitted to the FAERS database by pharmaceutical companies (mandatory reporting is required by manufacturers, distributors, or importers). Health care providers such as doctors (voluntary reporting), and patients themselves (voluntary reporting) report to the FDA directly through the MedWatch program. Those MedWatch reports are coded and included in the FAERS database. This report mainly consists of the mandatory reports, because the MedWatch reports are a small percentage (3 - 5%) of total reports. Link to the MedWatch summary report at the top of the page for a summary of the directly reported (voluntary) adverse events for this drug.The number of reports included here might differ somewhat from the number of reports in the downloadable quarterly FAERS reports and in the online FAERS dashboard, due to lags in reporting, drug name differences, duplicates, and other factors. Open FDA states that it only includes the most recent version of a case report. It also adds the disclaimer: "Do not rely on openFDA to make decisions regarding medical care. While we make every effort to ensure that data is accurate, you should assume all results are unvalidated."

FDA uses the "MedDRA" classification system to describe reported adverse reactions. MedDRA is a standardized medical terminology that facilitates sharing of regulatory information internationally. In some cases, "patient friendly" terms for the layman designated by MedDRA have been substituted for medical jargon. Please contact us with questions or comments about this report.