[Urinary concentration and antibacterial effect of short and long acting tetracycyline]

Forty-one hospitalized patients, of whom the majority had asymptomatic bacteriuria, were randomly divided into 4 treatment groups. They were given either tetracycline HCl 1 g, or tetracycline HCl + terpenes 100 mg, or minocycline 200 mg, or cotrimoxazole (sulfamethoxazole 1.6 g + trimethoprim 320 mg), daily for one week. A large number of bacteria were resistant to tetracyclines. The urine was sterilized in 14 out of 24 patients receiving tetracyclines and in all of the 17 patients receiving cotrimoxazole. The mean urinary concentration of tetracycline was 20 times higher than that of minocycline. The 24-h urinary excretion of tetracyclines was slightly higher in patients receiving the combination of terpenes and tetracycline, but these differences in urinary excretion did not appear to have any influence on the antibacterial effect of tetracyclines.