Urinary MHPG and clinical response to amitriptyline in depressed patients

The authors treated 18 rigorously diagnosed depressed patients with amitriptyline after baseline urine samples were collected for the measurement of 3-methoxy-4-hydroxphenylglycol (MHPG). Neither age nor severity of depression before treatment correlated with MHPG excretion. There was also no significant correlation between baseline MHPG excretion and clinical response at the end of at least 25 days' treatment with amitriptyline. The authors discuss the relevance of amitriptyline and nortriptyline plasma levels to MHPG and the noradrenergic/serotonergic theories of depression.