Effect of oxytetracycline on bacterial intestinal metabolism of neutral sterols and on serum lipids.

The effect of oral oxytetracycline administration to five healthy male volunteers on intestinal bacterial metabolism of faecal neutral sterols was studied. A reduction in bacterial transformation of cholesterol to coprostanol and coprostanone was observed which lasted 1-2 weeks after 5 days' intake of oxytetracycline (1000 mg/day). In addition, a reduction in the amount of esterified neutral sterols in faeces was observed. The significant changes in the intestinal metabolism of cholesterol had no effect on the levels of serum cholesterol, HDL-cholesterol, LDL-cholesterol, or triglycerides.