<ul>
	<li>Hypersensitivity to the active substance or to any of the excipients</li>
	<li>Moderate to severe hepatic impairment, i.e., Child-Pugh class B or C.</li>
	<li>Baseline values of liver aminotransferases, i.e., aspartate aminotransferases (AST) and/or alanine aminotransferases (ALT), greater than 3 times the upper limit of normal</li>
	<li>Concomitant use of cyclosporine A.</li>
	<li>Pregnancy</li>
</ul>

<p>Special warnings and precautions for use Liver aminotransferase levels must be measured prior to initiation of treatment and subsequently at monthly intervals for the duration of treatment with Bosentan. ln addition, liver aminotransferase levels must be measured 2 weeks after any dose increase.</p>