Trimethoprim alone in the treatment of urinary tract infections: eight years of experience in Finland.

In Finland the usage of trimethoprim (TMP) alone constitutes about 25% of all drug usage for urinary tract infections. Despite this widespread use the proportion of TMP-resistant strains is almost same as it is in countries where only the combination of trimethoprim-sulfamethoxazole (TMP-SMZ) has been used. In general, strains resistant to TMP were seldom found; only in closed wards did the use of trimethoprim result in an increase in the proportion of resistant strains. In the treatment of acute urinary tract infections, TMP alone (dose, 160 mg taken twice daily for seven days) gave a result as good as that of TMP-SMZ (94.5% vs. 90.6%) and a better result than cephalexin (98.3% vs. 82.1%). TMP proved suitable as a single agent in the treatment of urinary tract infections in outpatients. In a study of long-term treatment, TMP (dose, 100 mg taken once daily), was more effective than nitrofurantoin, methenamine hippurate, TMP-SMZ, or placebo. Fewer adverse effects were associated with TMP than with the other drugs.