<p>The initial half life of risedronic acid is approximately 1.5 hours<sup class="text-reference-group"><a class="reference-popover-link" data-content="Thompson Micromedex (2004). Usp Vol I Drug Info Health Vol: Volume I (USP DI: v.1 Drug Information for the Health Care Professional) (24th ed.). Thompson PDR. (ISBN 1563634635)" href="#reference-T536">3</a></sup>, with a terminal half life of 561 hours<sup class="text-reference-group"><a class="reference-popover-link" data-content="Official drug label" href="#label-reference">Label</a></sup>.</p>