Fezolinetant Side Effects

Medically reviewed byEditorial Medical Review, MD, NAMS-CMP

Last reviewed: 6/2/2026 · Verify credentials →

Fezolinetant side-effect incidence rates below are drawn from FDA prescribing information and clinical trials. Most common effects are gastrointestinal and peak during dose changes.

⚠ Boxed warning

Boxed warning (added September 2024): risk of rare but serious liver injury. Obtain LFTs before initiation and monitor periodically. Discontinue immediately if symptoms of hepatic injury appear (fatigue, RUQ pain, jaundice, dark urine).

Common side effects(5)

Incidence rates from clinical trials. Individual experience varies.

Fezolinetant common side effects with incidence rates
Effect	Incidence	Note
Abdominal pain	4.3%	Generally mild to moderate
Diarrhea	3.9%
Insomnia	3.9%
Back pain	3.0%
Hot flush (paradoxical, early)	2.6%	Usually resolves within weeks

Serious side effects(2)

Less common but require medical attention.

Elevated hepatic transaminases (ALT/AST). Monitor LFTs at baseline, months 3/6/9, then as clinically indicated. Discontinue if ≥3× ULN with symptoms or ≥5× ULN asymptomatic.
Drug-induced liver injury. Rare but reported; recent FDA boxed warning added 2024 after post-market cases

Managing side effects(4)

Get baseline LFTs before starting and do not skip the month-3 follow-up
Call your clinician immediately for nausea, fatigue, RUQ pain, or jaundice (liver injury signs)
Take with or without food — no meal restrictions
Allow 4-8 weeks for full effect on hot-flash frequency and severity

Sources(4)

Was this Fezolinetant side-effects guide helpful?

Fezolinetant Side Effects

Medically reviewed byEditorial Medical Review, MD, NAMS-CMP

Last reviewed: 6/2/2026 · Verify credentials →

Fezolinetant side-effect incidence rates below are drawn from FDA prescribing information and clinical trials. Most common effects are gastrointestinal and peak during dose changes.

⚠ Boxed warning

Common side effects(5)

Incidence rates from clinical trials. Individual experience varies.

Fezolinetant common side effects with incidence rates
Effect	Incidence	Note
Abdominal pain	4.3%	Generally mild to moderate
Diarrhea	3.9%
Insomnia	3.9%
Back pain	3.0%
Hot flush (paradoxical, early)	2.6%	Usually resolves within weeks

Serious side effects(2)

Less common but require medical attention.

Elevated hepatic transaminases (ALT/AST). Monitor LFTs at baseline, months 3/6/9, then as clinically indicated. Discontinue if ≥3× ULN with symptoms or ≥5× ULN asymptomatic.
Drug-induced liver injury. Rare but reported; recent FDA boxed warning added 2024 after post-market cases

Managing side effects(4)

Get baseline LFTs before starting and do not skip the month-3 follow-up
Call your clinician immediately for nausea, fatigue, RUQ pain, or jaundice (liver injury signs)
Take with or without food — no meal restrictions
Allow 4-8 weeks for full effect on hot-flash frequency and severity

Sources(4)

Was this Fezolinetant side-effects guide helpful?