Concentrations of metronidazole and tinidazole in female reproductive organs after a single intravenous infusion and after repeated oral administration.

Concentrations of metronidazole and tinidazole in serum and gynecological organs were analyzed after a single 500 mg intravenous infusion and after three days of treatment with 400 mg t.i.d. of metronidazole or 500 mg b.i.d. of tinidazole. The studies were performed in 67 patients subjected to hysterectomy and/or oophorectomy because of myomatosis uteri, carcinoma uteri or endometriosis. At the time of organ removal (about 30 min after infusion), metronidazole and tinidazole levels in serum were 14.5 ± 0.45 mg/l and 12.3 ± 0.38 mg/l, respectively. Concentrations of both drugs in the uterus and Fallopian tube were about the same as the simultaneous serum levels and concentrations in the ovaries about 55% thereof. At steady-state, the concentrations of tinidazole in serum (23.5 ± 1.0 mg/l) were remarkably higher than those of metronidazole (13.5 ± 0.84 mg/l) about three hours after the last oral dose. Drug concentrations in organs of the female reproductive tract were 70 to 100% those of the simultaneous serum levels.