Antibiotic treatment of acute salpingitis. A study of plasma concentrations of two tetracyclines (doxycycline and lymecycline).

A group of 782 patients with a diagnosis of acute salpingitis (a few of the patients because of other infection in the pelvis) were treated with the recommended oral dose of doxycycline (200 mg the first day and 100 mg once daily for at least the following 9-12 days) in combination with 1 g benzyl penicillin and 0.6 g procaine penicillin twice daily intramuscularly for 5-7 days. The plasma concentrations of doxycycline were determined on the third day of treatment before the next dose was given. In 26.5% of the patients the concentrations were below 1 microgram/ml plasma, considered as the minimum therapeutic level. The dose of doxycycline was increased to 200 mg a day in these patients and the plasma concentrations increased accordingly. In another group of 80 patients, 40 were treated with the standard doxycycline dose, and the other 40 patients with the standard lymecycline dose (300 mg twice a day). The plasma concentrations, determined before the dose on the third day, were below 1 microgram/ml in 35% of the patients treated with doxycycline, and in 5% of those treated with lymecycline. Since acute salpingitis in most cases is a serious complication to a lower genital tract infection, often a sexually transmitted disease caused by tetracycline-sensitive organisms, the importance of achieving and determining the therapeutic plasma concentrations of tetracyclines is stressed.