<p>2.3 hours for orally inhaled levodopa<sup class="text-reference-group"><a class="reference-popover-link" data-content="Official drug label" href="#label-reference">Label</a></sup>. Oral levodopa has a half life of 50 minutes but when combined with a peripheral dopa decarboxylase inhibitor, the half life is increased to 1.5 hours<sup class="text-reference-group"><a class="reference-popover-link" data-content="Sinemet FDA Label" href="#reference-F4579">8</a></sup>.</p>