<p>The elimination half-life ranges from 2.4-9.3 hours in healthy adults <sup class="text-reference-group"><a class="reference-popover-link" data-content="Benylin Chesty Coughs UK MHRA Product Information" href="#reference-F3394">18</a>,<a class="reference-popover-link" data-content="Electronic Medicines Compendium: Nytol One-A-Night (diphenhydramine hydrochloride) Monograph" href="#reference-L5287">13</a></sup>. The terminal elimination half-life is prolonged in liver cirrhosis <sup class="text-reference-group"><a class="reference-popover-link" data-content="Electronic Medicines Compendium: Nytol One-A-Night (diphenhydramine hydrochloride) Monograph" href="#reference-L5287">13</a></sup>.</p>