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Dianabol For Sale: Effectivity And Regulation

# Tofacitinib (Xeljanz®) – A Comprehensive Overview

**Tofacitinib** is an oral Janus kinase (JAK) inhibitor approved in many countries for the treatment of moderate‑to‑severe rheumatoid arthritis (RA), psoriatic arthritis, and ulcerative colitis. It was first marketed under the brand name *Xeljanz®* by Pfizer (now Janssen). Below you will find a detailed look at its mechanism of action, pharmacology, therapeutic uses, dosing recommendations, safety considerations, and real‑world experience.

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## 1. Mechanism of Action

| Step | What Happens |
|------|--------------|
| **Binding** | Tofacitinib selectively inhibits JAK1 and JAK3 (with weaker inhibition of JAK2). |
| **Signal Transduction** | This blocks the phosphorylation of STAT proteins that are essential for cytokine receptor signaling. |
| **Immune Modulation** | By dampening downstream signals from multiple pro‑inflammatory cytokines (e.g., IL‑6, IFN-γ, IL‑2), it reduces T cell activation and B cell differentiation. |
| **Clinical Effect** | Decreases inflammatory processes underlying autoimmune diseases such as rheumatoid arthritis (RA) or psoriatic arthritis (PsA). |

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## 3.  Mechanism of Action – Rituximab

> **Target:** CD20 protein on the surface of mature B‑lymphocytes
> **Delivery:** Intravenous infusi

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