Plasma catecholamine metabolites and treatment response at neuroleptic steady state.

Using either haloperidol or perphenazine in a fixed-dose protocol, plasma free homovanillic acid (HVA) and methoxyhydroxyphenethylglycol (MHPG) were decreased in 37 nonorganic psychotic inpatients at neuroleptic steady state (7-9 days) in comparison with pretreatment values. The data indicate that the magnitude of the decline in HVA and MHPG was associated with treatment response and not with neuroleptic plasma levels.