Effect of a novel monamine oxidase-a inhibitor,bw 1370U87, on urinary 3-methoxy-4-hydroxyphenylglycol in normal volunteers

Urinary 3-methoxy-4-hydroxyphenlglycol (MHPG) levels were measured in 14 normal volunteers during a Phase I study of the novel, reversible monoamine oxidase-A (MAO-A) inhibitor BW 1370U87 targeted for the treatment of depression. baseline MHPG excretion (day 0) showed a significant diurnal increase (n = 14, P < 0.05) between 1200 and 2000 h. Oral administration of BW 1370U87 produced significant (35-45% maximal, P < 0.05) decreases from these basal levels during the same 1200-2000 h time interval Twenty-four hours after the dose (dose was given at 0800 h), urinary MHPG levels returned to baseline, consistent with a reversible mechanism of inhibition by BW 1370U87. Decreases in urinary MHPG did not appear to be dose-dependent between 200-800 mg BW 1370U87 per day, suggesting that maximal MAO-A inhibition was achieved at the 200 mg dose. These effects on MHPG excretion may be helpful in predicting the efficacy of BW 1371370U87 in the treatment of depression. © 1993 wiley-Liss, Inc.