<p>Pimecrolimus is a macrolactam and is a derivative of ascomycin. It is an immunosuppressant which inhibits the activation of T-cells and prevents the release of inflammatory mediators from mast cells. It is used for the short term or intermittent long term treatment for mild to moderate atopic eczema.<br />
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The mechanism of action of pimecrolimus in atopic dermatitis is not known. While the following have been observed, the clinical significance of these observations in&nbsp;atopic dermatitis&nbsp;is not known. It has been demonstrated that pimecrolimus binds with high&nbsp;affinity&nbsp;to macrophilin-12 (FKBP-12) and inhibits the calcium-dependent phosphatase, calcineurin. As a consequence, it inhibits&nbsp;T cell&nbsp;activation by blocking the&nbsp;transcription&nbsp;of early cytokines. In particular, pimecrolimus inhibits at nanomolar concentrations&nbsp;Interleukin-2&nbsp;and interferon gamma (Th1-type) and&nbsp;Interleukin-4&nbsp;and&nbsp;Interleukin-10&nbsp;(Th2-type)&nbsp;cytokine&nbsp;synthesis in human T-cells. In addition, pimecrolimus prevents the release of inflammatory cytokines and mediators from mast cells&nbsp;in vitro&nbsp;after stimulation by&nbsp;antigen/IgE.</p>