Phenelzine in depressed patients. Effects on urinary MHPG excretion in relation to clinical response

Depressed patients' treatment with the monoamine oxidase inhibiting antidepressant, phenelzine, developed marked reductions in urinary 3-methoxy-4-hydroxyphenylglycol (MHPG) excretion. Pretreatment levels of urinary MHPG and platelet monoamine oxidase activity were significantly correlated with each other, but the magnitude of reduction in these measurements produced by phenelzine treatment did not correspond as closely. Similarly, MHPG levels were not significantly different in patients with antidepressant responses to the drug compared to nonresponders.