A randomized trial of acetohydroxamic acid for the treatment and prevention of infection-induced urinary stones in spinal cord injury patients.

Acetohydroxamic acid is known to inhibit bacterial urease activity, thus, reducing urinary ammonia levels. A double-blind placebo-controlled clinical trial of acetohydroxamic acid was conducted at 12 Veterans Administration spinal cord injury units. A total of 210 male spinal cord injury patients with chronic urea-splitting urinary infection was enrolled for a scheduled followup of 2 years. The study data support the usefulness of acetohydroxamic acid in reducing urinary ammonia. At every followup visit the acetohydroxamic acid patients with stones had decreases in ammonia of 30 to 48 mg. per dh., while the placebo patients had increases in ammonia. Acetohydroxamic acid also retarded stone growth. Patients with stones treated with acetohydroxamic acid exhibited significantly longer intervals from randomization to first stone growth than patients treated with placebo (p less than 0.005, medians 15 versus 9 months). Acetohydroxamic acid reduced significantly the proportion of patients with stone growth at 12 months (33 versus 60 per cent, p equals 0.017). This decrease was diminished at 24 months (42 versus 60 per cent, p equals 0.260). Patient attrition was 31 per cent in the placebo group and 62 per cent in the acetohydroxamic acid group, the latter attrition being primarily owing to patient request because of mild symptoms. Of the acetohydroxamic acid and placebo patients 62 and 29 per cent, respectively, reported drug side effects but all were reversible and no unanticipated or life-threatening reactions occurred.