Dear Dr.

Studies have shown no significant difference in serum half-life of Doxycycline  in individuals with normal and severely impaired renal function. As well as. excretion of Doxycycline by the kidney is about 40%/72 hours in individuals with normal function (creatinine clearance about 75 mL/min). This percentage excretion may fall as low as 1 to 5%/72 hours in individuals with severe renal insufficiency (creatinine clearance below 10 mL/min).

Best regards....

Primarily, doxycycline is excreted in bile to feces, and part of doxycycline is inactivated in the liver and 40 % of it is excreted by kidneys in urine, while the majority of first-generation tetracyclines are not metabolized Instead, they are most often eliminated by renal excretion.

Hi,Dr.Jinan

The Doxycycline is  concentrated by the liver in the bile and excreted in the urine and feces at high concentrations in a biologically active form.

Half life 18-22 hours

The Doxycycline is concentrated by the liver in the bile and excreted in the urine and feces at high concentrations in a biologically active form.