Studies on the absorption and distribution of doxycycline in normal patients and in patients with severely impaired renal function.

Doxycycline, a recently synthesized analogue of tetracycline, was given to 16 patients with normal renal function and to 14 patients with severely impaired renal function. Serum concentrations in the two groups following a single dose were followed after absorption. The rate of clearance from the plasma following a single dose did not differ significantly in the two groups despite low urinary concentrations in patients with renal failure. No accumulation of doxycycline occurred in the serum of three normal patients or of nine patients with renal failure when treated with either 200 mg. daily or 200 mg. initially followed by 100 mg. daily for up to 15 days.