Ritlecitinib

LITFULO

Open Ritlecitinib in the interactive console ↗

What it isAn oral covalent inhibitor of JAK3 and the TEC kinase family, for severe alopecia areata, including adolescents.

Why this oneIt extends the JAK-inhibitor alopecia story to age twelve and up, with kinase selectivity intended to spare the broader JAK1/2 effects.

What limits itIt still carries the JAK-class warnings — infection, thrombosis, malignancy, cardiovascular events — and hair regrowth reverses if it is stopped; screen for tuberculosis and avoid live vaccines.

FDA label

Read the full label on DailyMed ↗

BOXED WARNING Serious infections (incl. TB — screen/treat latent TB; monitor); increased all-cause mortality incl. sudden CV death (another JAK inhibitor vs TNF blockers in RA); malignancies (lymphoma, lung cancer); MACE; thrombosis (PE, venous/arterial).

FDA dosing	Population	Start	Target	Max
Severe alopecia areata	Adults and adolescents ≥12 yr	50 mg QD	50 mg QD	50 mg QD

Renal Undefined

Hepatic No adjustment for mild-moderate (Child-Pugh A-B); not recommended in severe (Child-Pugh C)

Instructions

Swallow capsules whole; do not crush, split, or chew; with or without food
Missed dose: take ASAP unless <8 h before next dose (then skip)
Before initiation: TB evaluation, viral hepatitis screening, update immunizations (incl. herpes zoster); do not start if ALC <500/mm3 or platelets <100,000/mm3
Check ALC and platelets at baseline and at 4 wks; discontinue if platelets <50,000/mm3; interrupt if ALC <500/mm3 (may restart on recovery)
Treatment interruption <6 wks not expected to cause significant loss of regrown hair

Cautions

Serious/opportunistic infections incl. TB, sepsis, herpes zoster (multi-dermatomal) — avoid with active serious infection; interrupt for serious infection
Mortality, malignancy, MACE, and thrombosis risks (JAK-inhibitor class; boxed) — avoid in patients at increased thrombosis risk; discontinue after MI or stroke
Hypersensitivity incl. anaphylaxis — discontinue for clinically significant reaction
Hypoglycemia in patients with diabetes — consider increased glucose monitoring
Lab abnormalities: lymphopenia, thrombocytopenia, ALT/AST elevations (interrupt if DILI suspected), CPK elevations
Avoid live attenuated vaccines during or shortly before treatment

Adverse reactions

Headache
Diarrhea
Acne
Rash
Urticaria
Folliculitis
Pyrexia
Atopic dermatitis
Dizziness
Increased CPK
Herpes zoster
Decreased RBC count
Stomatitis

Pregnancy Insufficient human data; fetotoxicity/malformations in animals at ≥49x MRHD; exposure registry 1-877-390-2940

Lactation Do not breastfeed during treatment and for ~14 h after last dose (~6 half-lives)

NO BOXED WARNINGS

Classes and tags

Clinical profile

Direct muscarinic antagonism0 / 4

Mechanism of action: Ritlecitinib ballicule

Ritlecitinib ballicule: receptor binding, kinetics and half-life diagram

Open Ritlecitinib in the interactive console ↗

Memory aids: mascots and interaction avatars

Ritlecitinib LITFULO mascot mnemonic cartoon — **“Little Foo Foo, the Riddle City nibbler”**
jack → Janus kinase (JAK) inhibitor

Open Ritlecitinib in the interactive console ↗