<p><strong>Renal impairment</strong>&nbsp;(creatinine clearance &lt;25 mL/min): Maximal mean plasma levels were found to be twice as high as in normal volunteers, and the terminal half-life was prolonged to approximately 14 hours, resulting in much higher (approximately 6-fold on average) AUC values.<br />
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<strong>Hepatic impairment</strong>: No specific studies were conducted in this population. As tizanidine is extensively metabolized in the liver by the CYP1A2 enzyme, hepatic impairment may increase its systemic exposure. Tizanidine is contraindicated in patients with severe hepatic impairment.<br />
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<strong>Geriatrics</strong>&nbsp;(65 years of age and older): Pharmacokinetic data in this population are limited.<br />
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<strong>Gender</strong>: Gender has no clinically significant effect on the pharmacokinetics of tizanidine.<br />
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<strong>Ethnicity</strong>: The impact&nbsp;of ethnic sensitivity and race on the pharmacokinetics of tizanidine has not been studied.</p>