Fezolinetant

Introduction Overview

Generic Name

fezolinetant

Brand Name

Veozah

Dosage Form

tablets, for oral use

Drug Class

Miscellaneous central nervous system agents

Pharmacokinetics

Absorption:
Fezolinetant is administered orally as a tablet and exhibits reliable absorption from the gastrointestinal tract. The bioavailability is sufficient to produce clinical effects with once-daily dosing. Food does not significantly affect its absorption, allowing administration with or without food, which enhances patient compliance. Peak plasma concentrations typically occur within hours post-dose, enabling rapid onset of action essential for symptomatic relief of vasomotor symptoms.

Distribution:
Following absorption, fezolinetant demonstrates moderate plasma protein binding, facilitating its distribution primarily to central nervous system tissues where its site of action resides. It efficiently crosses the blood-brain barrier to reach neurokinin 3 (NK3) receptors in the hypothalamic thermoregulatory centers. The volume of distribution indicates a balance between plasma and tissue residency, ensuring adequate receptor occupancy. Pharmacokinetic studies have shown consistent distribution profiles across adult patients, with no need for dosage adjustments based on body weight.

Metabolism:
Fezolinetant undergoes hepatic metabolism predominantly via the cytochrome P450 enzyme system, specifically CYP1A2 isoenzyme. The metabolism involves oxidative processes yielding metabolites, some of which are inactive while others may contribute minor pharmacodynamic properties. The involvement of CYP1A2 underscores the potential for drug-drug interactions with inhibitors or inducers of this enzyme. Hepatic enzyme function significantly influences the metabolic clearance rate. Patients with hepatic impairments require careful monitoring or contraindication considerations due to altered metabolism and accumulation risks.

Elimination:
The elimination of fezolinetant and its metabolites occurs mainly via renal excretion, with some biliary clearance. The half-life supports once-daily dosing, maintaining plasma concentrations sufficient for therapeutic benefit over 24 hours. Renal function can affect the elimination kinetics; therefore, patients with severe renal impairment or failure are contraindicated for use. Liver function also influences elimination indirectly through metabolic capacity. Clinical trials have shown elimination is consistent in the general adult population, but monitoring is required for patients with coexisting organ dysfunction to avoid toxicity.

Dosage Forms

Available Dosage Forms:
- Oral tablets available in a 45 mg strength.

Dosages for Adults and Adolescents:
- Recommended dosage is 45 mg orally once daily.
- Tablets should be swallowed whole with fluid and can be taken with or without food.
- Consistency in timing of administration is recommended to maintain stable drug levels.

Specific Patient Populations:
- Not recommended for patients with severe liver impairment, cirrhosis, or severe kidney problems.
- No dosing adjustments are provided for mild to moderate hepatic or renal impairment; however, monitoring is advised.
- Use in pregnant or breastfeeding women is not recommended due to insufficient data.
- Pediatric and adolescent use has not been established.

Clinical guidelines emphasize adherence to the 45 mg oral tablet once daily regimen for treatment of moderate to severe vasomotor symptoms related to menopause. Missed doses should be taken on the same day with a minimum 12-hour interval before the next dose; however, if this cannot be done, patients should return to their normal schedule the next day.

Mechanism Of Action

Veozah (fezolinetant) operates as a selective neurokinin 3 (NK3) receptor antagonist, acting centrally within the hypothalamus where thermoregulatory processes are controlled. The NK3 receptor is a G-protein coupled receptor activated by neurokinin B (NKB), a tachykinin neuropeptide involved in regulating body temperature and reproductive hormone balance. In menopausal women, estrogen levels decline, disrupting the equilibrium between estrogen and NKB, resulting in vasomotor symptoms such as hot flashes and night sweats.

By competitively inhibiting NK3 receptors, fezolinetant blocks the binding and downstream signaling of NKB in the thermoregulatory center, effectively restoring the homeostatic balance disrupted by estrogen deficiency. This receptor blockade modulates neuronal activity in the median preoptic nucleus of the hypothalamus, normalizing heat dissipation responses and suppressing the frequency and severity of hot flashes.

Pharmacodynamically, fezolinetant’s action leads to a reduction in the pulsatile secretion of gonadotropin-releasing hormone (GnRH) and subsequently luteinizing hormone (LH), aligning with the chemical pathways associated with temperature regulation and menopausal symptoms. Unlike hormone replacement therapies, Veozah does not contain estrogen; hence, it avoids risks associated with estrogen exposure such as endometrial hyperplasia or thromboembolic events.

Clinical studies corroborate the sustained efficacy of fezolinetant in reducing vasomotor symptom burden, with onset of action observed within one week of administration and persistent benefits extending through at least one year of treatment. Comparative analyses indicate that its nonhormonal mechanism provides an alternative therapeutic pathway especially suited for patients contraindicated or intolerant to hormone replacement therapies.

Pharmacological Actions

Selective antagonism of neurokinin 3 (NK3) receptors in the hypothalamic thermoregulatory center.
Reduction of vasomotor symptom frequency and severity by modulating neurokinin B (NKB) activity.
Normalization of hypothalamic temperature control pathways disrupted by decreased estrogen during menopause.
Suppression of gonadotropin-releasing hormone (GnRH) pulsatility, indirectly influencing luteinizing hormone secretion.
Nonhormonal mechanism avoiding estrogen-related risks such as thromboembolism and hormone-dependent cancers.
Rapid onset of therapeutic effect, typically within one week of initiation.
Sustained relief of menopausal hot flashes and night sweats over long-term treatment.
Minimal central nervous system depression or sedation compared to other CNS agents.
Favorable pharmacokinetic profile permitting once-daily oral dosing.
Metabolized primarily via hepatic CYP1A2 reducing drug accumulation risk with normal liver function.
No significant interference with estrogen receptors ensuring safety in hormone-sensitive tissues.
Potential utility as an alternative to selective serotonin reuptake inhibitors (SSRIs) in managing vasomotor symptoms without weight gain.

Therapeutic Or Clinical Uses

Treatment of moderate to severe vasomotor symptoms (hot flashes and night sweats) associated with menopause.
Nonhormonal option for menopausal women who cannot or prefer not to use hormone replacement therapy.
Management of menopausal symptoms that interfere with quality of life and daily functioning.
Alternative for patients with contraindications to estrogen-containing therapies such as history of breast cancer or thromboembolic events.
Adjunctive agent in clinical scenarios aiming to reduce hormone exposure while managing hot flashes.
Potential use in patients experiencing intolerable side effects from SSRIs or SNRIs prescribed for vasomotor symptoms.
Provides symptomatic relief aiding sleep quality by reducing night sweats and associated discomfort.
May improve overall menopausal symptom burden leading to enhanced physical and psychological well-being.
Used in women aged generally between 45 to 55 years undergoing natural menopause transition.
Not approved for use in premenopausal women or for symptoms unrelated to menopause.

Side Or Adverse Effects

Common gastrointestinal symptoms including stomach (abdominal) pain and diarrhea.
Insomnia or difficulty sleeping episodes reported in some patients.
Back pain as a non-specific musculoskeletal complaint noted during therapy.
Occurrence of hot flashes or hot flushes paradoxically while on treatment.
Rare but serious risk of liver injury marked by elevated liver enzymes and hepatotoxicity.
Signs of liver dysfunction such as jaundice, pruritus, nausea, vomiting, and right upper quadrant abdominal pain requiring immediate medical evaluation.
Potential for increased liver blood test values necessitating routine monitoring before and during treatment.
Fatigue and malaise linked to hepatic adverse effects.
Possible drug-related allergic reactions or hypersensitivity though infrequent.
No significant reports of cardiovascular or thromboembolic adverse events.
Minimal sedation or cognitive impairment unlike other CNS agents.
Absence of hormone-related side effects such as breast tenderness or vaginal bleeding.

Precautions

Regular hepatic function monitoring is essential prior to initiation and periodically during treatment due to hepatotoxicity risk.
Avoid use in patients with pre-existing liver disease including cirrhosis or hepatitis.
Caution in individuals with renal impairment; Veozah is contraindicated in severe kidney dysfunction.
Avoid concomitant use with potent CYP1A2 inhibitors as they increase fezolinetant plasma concentrations leading to toxicity.
Patient education to recognize early symptoms of liver injury; prompt discontinuation upon symptom onset.
No established safety data in pregnancy and breastfeeding; therefore, avoid use in these populations.
Careful assessment of all concomitant medications to prevent significant drug-drug interactions.
Monitor for worsening of other medical conditions that may arise or be exacerbated during therapy.
Adjustment or avoidance in elderly patients with hepatic or renal compromise due to pharmacokinetic variability.
Counsel patients on consistent dosing time to maintain therapeutic plasma levels.
Avoid breaking, chewing, or crushing tablets to ensure proper delivery and bioavailability.
Inform patients about potential gastrointestinal side effects and advise supportive care if needed.

Warnings

Risk of serious liver injury including rare cases of severe hepatotoxicity.
Mandatory liver enzyme testing before therapy, monthly for first three months, and at months 6 and 9.
Immediate discontinuation required if alanine aminotransferase (ALT) or aspartate aminotransferase (AST) levels exceed 5 times upper limits of normal (ULN), or if elevations are >3x ULN with concurrent total bilirubin >2x ULN.
Contraindicated in patients with aminotransferase or bilirubin elevations ≥ 2 times ULN at baseline.
Do not initiate treatment in patients showing signs or laboratory evidence of liver dysfunction.
Educate patients to promptly report new fatigue, nausea, vomiting, itching, jaundice, pale stools, or dark urine.
Periodic monitoring of hepatic laboratory parameters is critical to safely continue therapy.
Caution advised when combined with caffeine-containing products as it may increase plasma levels and side effect risks.
Avoid use with CYP1A2 inhibitors to prevent excessive drug exposure worsening hepatotoxicity potential.
No known significant cardiac or other systemic warnings have been identified.
Use exclusively for approved indication to avoid unstudied risks.
Advise against use in populations without established safety and efficacy data, such as pediatric or pregnant patients.

Contraindication

Known cirrhosis or significant liver disease.
Severe renal impairment or kidney failure.
Active liver problems including elevated liver enzymes or bilirubin ≥ 2 times ULN before treatment initiation.
Concurrent use with strong CYP1A2 inhibitors such as fluvoxamine, ciprofloxacin, or other listed agents.
Hypersensitivity to fezolinetant or any formulation components.
Pregnancy due to lack of safety data.
Breastfeeding women owing to unknown excretion and effects in infants.
Patients unable to comply with required liver monitoring protocols.
Use outside of the approved indication for vasomotor symptoms of menopause.
Patients with a history of severe adverse reactions to NK3 receptor antagonists.
Patients with unexplained abnormal liver function tests.

Drug Interactions

Strong inhibitors of CYP1A2 (e.g., fluvoxamine, ciprofloxacin, enoxacin) can increase fezolinetant plasma levels leading to toxicity.
Oral contraceptives may interact by affecting drug metabolism via CYP pathways.
Mexiletine and methoxsalen are CYP1A2 inhibitors that may elevate fezolinetant concentrations.
Other CYP1A2 inhibitors such as vemurafenib, acyclovir, and cimetidine also decrease fezolinetant metabolism.
Piperine and zileuton can inhibit CYP1A2, thus potentiating adverse effects.
Peginterferon alpha-2a may have additive hepatic toxicity when combined with fezolinetant.
No significant interactions reported with cytochrome P450 inducers requiring dose adjustment but caution advised.
Concurrent caffeine intake can increase fezolinetant levels; patients should avoid caffeine-containing products.
No known interactions with commonly prescribed antihypertensives or lipid-lowering agents.
Limited data available on interaction with warfarin or anticoagulants; close monitoring advised if coadministered.
Interactions with supplements such as green tea extract may influence metabolism indirectly.
Patients should inform healthcare providers of all prescribed, over-the-counter, and herbal products to avoid unexpected interactions.
No significant pharmacodynamic interactions with other CNS agents reported.

Preparations Of The Drug

Active ingredient: fezolinetant at 45 mg per tablet.
Inactive ingredients include ferric oxide, hydroxypropyl cellulose, hypromellose, low-substituted hydroxypropyl cellulose, magnesium stearate, mannitol, microcrystalline cellulose, polyethylene glycol, talc, and titanium dioxide.
Tablet formulation designed for oral administration, with coatings to enhance bioavailability and stability.
Tablets should be stored at controlled room temperature (68°F to 77°F / 20°C to 25°C) to maintain efficacy.
Packaging typically includes blister packs or bottles to protect from moisture and light.
Manufactured under stringent quality control per pharmaceutical standards ensuring dosage accuracy.
Non-hormonal chemical entity offering a novel treatment option in menopausal vasomotor symptom management.
Preparation avoids use of hormones, syrups, or injectable forms, simplifying administration and adherence.
Instructions emphasize ingestion of intact tablets without crushing or chewing to preserve pharmacokinetic profile.
Disposal recommendations follow FDA guidelines for unused medications to minimize environmental impact.