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What is Ruxolitinib and explain in detail?
Ruxolitinib, sold under the brand names Jakafi and Jakavi, is a medication approved in the US in 2011 for the treatment of intermediate or high-risk myelofibrosis, a type of myeloproliferative disorder that affects the bone marrow; polycythemia vera (PCV), when there has been an inadequate response to or intolerance of hydroxyurea; and steroid-refractory acute graft-versus-host disease. Ruxolitinib is a janus kinase inhibitor.It was developed and marketed by Incyte Corp in the US under the brand name Jakafi, and by Novartis elsewhere in the world, under the brand name Jakavi.

Medical uses
In the United States and the European Union, ruxolitinib is indicated for the treatment of disease-related splenomegaly or symptoms in adults with primary myelofibrosis (also known as chronic idiopathic myelofibrosis), post-polycythaemia-vera myelofibrosis, or post-essential thrombocythaemia myelofibrosis. It is also indicated for the treatment of adults with polycythaemia vera who are resistant to or intolerant of hydroxyurea. Ruxolitinib is also indicated for the treatment of steroid-refractory acute graft-versus-host disease in people who are twelve years of age and older, and for the treatment of chronic graft-versus-host disease (cGVHD) after failure of one or two lines of systemic therapy in people twelve years of age and older.In the United States, ruxolitinib cream is indicated for the topical treatment of mild to moderate atopic dermatitis and vitiligo.

Side effects
In myelofibrosis, the most common side effects include thrombocytopenia (low blood platelet counts), anaemia (low red blood cell counts), neutropenia (low levels of neutrophils), urinary tract infections (infection of the structures that carry urine), bleeding, bruising, weight gain, hypercholesterolaemia (high blood cholesterol levels), dizziness, headache and raised liver enzyme levels.In polycythaemia vera, the most common side effects include anemia (low red blood cell counts) and thrombocytopenia (low blood platelet count), bleeding, bruising,  hypercholesterolaemia (high blood cholesterol levels), hypertriglyceridemia (high blood fat levels), dizziness, raised liver enzyme levels and high blood pressure.In acute graft-versus-host disease, the most common hematologic adverse reactions include anemia, thrombocytopenia, and neutropenia. The most common nonhematologic adverse reactions include infections and edema.Immunologic side effects have included herpes zoster (shingles) and case reports of opportunistic infections. Metabolic side effects have included weight gain. Laboratory abnormalities have included alanine transaminase (ALT) abnormalities, aspartate transaminase (AST) abnormalities, and mildly elevated cholesterol levels.

Mechanism of action
Ruxolitinib is a janus kinase inhibitor (JAK inhibitor) with selectivity for subtypes JAK1 and JAK2.  Ruxolitinib inhibits dysregulated JAK signaling associated with myelofibrosis