Ruxolitinib is a Janus kinase (JAK) inhibitor indicated for the treatment of atopic dermatitis and vitiligo.

Atopic Dermatitis: Ruxolitinib cream is used for short-term, non-continuous topical treatment of mild to moderate atopic dermatitis in non-immunocompromised adult and pediatric patients aged 12 years and older, when the disease is not adequately controlled with topical prescription therapies or when such therapies are not appropriate.

Vitiligo: Ruxolitinib cream is indicated for the topical treatment of non-segmental vitiligo in adult and pediatric patients aged 12 years and older.

Ruxolitinib is a Janus kinase (JAK) inhibitor that selectively inhibits JAK1 and JAK2, which are involved in signaling pathways of various cytokines and growth factors essential for hematopoiesis and immune regulation. JAK signaling activates STAT proteins (signal transducers and activators of transcription), which move to the nucleus and regulate gene expression. The exact relationship between inhibition of specific JAK enzymes and therapeutic efficacy is not fully understood.

Absorption: Topical application leads to measurable plasma concentrations. No drug accumulation is observed after 28 days of daily use.

Distribution: Plasma protein binding is approximately 97%.

Metabolism: Ruxolitinib is mainly metabolized by CYP3A4 and to a lesser extent by CYP2C9.

Elimination: Mean terminal half-life is approximately 116 hours. The drug is excreted mainly via urine (74%) and feces (22%), with less than 1% excreted unchanged.

Administration Instruction: Ruxolitinib cream should not be used more than 60 gram per week or 100 gram per 2 weeks. It is for topical use only. It is not for intraocular, oral, or intravaginal use.

Recommended Dosage for Atopic Dermatitis: Patients should apply a thin layer of Ruxolitinib twice daily to affected areas of up to 20% body surface area. When signs and symptoms (e.g., itch, rash, and redness) of atopic dermatitis resolve it should be stopped. If signs and symptoms do not improve within 8 weeks, patients should be re-examined by registered doctor.

Recommended Dosage for Nonsegmental Vitiligo: Patients should apply a thin layer of Ruxolitinib twice daily to affected areas of up to 10% body surface area. Satisfactory patient response may require treatment with Ruxolitinib for more than 24 weeks. If the patient does not find the repigmentation meaningful by 24 weeks, the patient should be re-evaluated by registered doctor.

USE IN CHILDREN: The safety and effectiveness of Ruxolitinib in pediatric patients younger than 12 years of age with atopic dermatitis and nonsegmental vitiligo have not been established.

Ruxolitinib is a substrate of cytochrome P450 3A4 (CYP3A4). CYP3A4 inhibitors may increase systemic exposure of Ruxolitinib, while CYP3A4 inducers may reduce its plasma concentration and effectiveness.

Strong CYP3A4 Inhibitors: Concomitant use with strong CYP3A4 inhibitors should be avoided, as they may significantly increase Ruxolitinib exposure and raise the risk of adverse reactions.

Ruxolitinib is contraindicated in patients with known hypersensitivity to the drug or any of its components.

In Atopic Dermatitis: Common side effects include nasopharyngitis, diarrhea, bronchitis, ear infection, increased eosinophil count, urticaria, folliculitis, tonsillitis, and rhinorrhea.

In Non-segmental Vitiligo: Common side effects include application site acne, pruritus, nasopharyngitis, headache, urinary tract infection, erythema at application site, and pyrexia.

Due to serious adverse effects in adults such as infections, thrombocytopenia, anemia, and neutropenia, breastfeeding should be avoided during treatment with Ruxolitinib and for approximately four weeks after the last dose.

Serious Infections: Ruxolitinib should be avoided in patients with active serious infections. If infection develops, treatment should be interrupted until control is achieved. Patients should be monitored closely before and during therapy.

Mortality Risk: Increased risk of mortality, including cardiovascular death, has been observed with JAK inhibitors in certain high-risk patients.

Non-melanoma Skin Cancer: Basal and squamous cell carcinomas may occur. Regular skin examination and sun protection are recommended.

Major Cardiovascular Events (MACE): Smokers or past smokers are at increased risk. Discontinue if myocardial infarction or stroke occurs.

Thrombosis: If thromboembolic events occur, treatment should be stopped and appropriate management initiated.

Blood Disorders: Thrombocytopenia, anemia, and neutropenia may occur; CBC monitoring is required.

Pyrrolopyrimidines

Store below 30°C in a dry place, away from sunlight. Keep out of reach of children.