<p>The excretion of doxycycline by the kidney is about 40% over 72 hours in individuals with normal kidney function (creatinine clearance approximately 75 mL/min). This rate may fall as low as 1-5% over 72 hours in individuals with severe renal insufficiency (creatinine clearance below 10 mL/min). Some clinical studies have shown no major difference in serum half-life of doxycycline (range 18-22 hours) in patients with normal and severely impaired renal function. Hemodialysis does not affect serum half-life of doxycycline <sup class="text-reference-group"><a class="reference-popover-link" data-content="Official drug label" href="#label-reference">Label</a></sup>.</p>