Doxycycline in renal failure

Summary

Twelve patients with grossly impaired renal function were studied. Doxycycline in doses of 200 mg. the first day followed by 100 mg. every 24 hours for 6 days was administered. Glomerular filtration rate and effective renal plasma flow, defined as the clearance ofinulin and the clearance of PAH, respectively, were measured before and after the administration period. The serum concentration of active drug was measured twice daily, and the urinary drug excretion followed during the study. The individual levels of haemoglobin, uric acid, bilirubin, SGOT, SGPT and LDH before and after doxycycline administration were compared, and the concentrations of serum creatinine and blood urea followed by repeated measurements.

Glomerular filtration rate, effective renal plasma flow, serum creatinine and blood urea did not change significantly during doxycycline administration, neither did any of the other parameters measured. The individual serum levels of doxycycline varied considerably, but there was no tendency to accumulation of active drug in serum. No correlation between serum concentration and degree of renal failure was found. The urinary concentrations of active doxycycline were in the same range as those of the serum. Only a small fraction of the daily dose ofdoxycyline was excreted in the urine. The present study supports earlier works claiming that treatment with doxycycline does not lead to deterioration of renal function or drug accumulation, even in advanced renalfailure.