Absence of Age Effect on Plasma Haloperidol Neuroleptic Levels in Psychiatric Patients

Abstract

Plasma neuroleptic levels in 41 patients (21 men, 20 women, aged 18 to 74) on haloperidol therapy were examined in relation to their age by means of radioreceptor assay. There was no significant difference among three age groups (below 45 years, 46 to 60 years, over 60 years) in the ratio of the plasma neuroleptic level to daily dose (nM/mg/kg), but a significant difference in the plasma neuroleptic level was found between the average values in parkinsonian (19.1 +/- 8.5 nM, M +/- SD) and nonparkinsonian (5.5 +/- 3.0 nM, M +/- SD) patients. There was, however, no significant difference in the incidence of parkinsonian symptoms between the young (below 60 years) and the old (over 60 years) age groups. These results suggest that in contrast to the previously reported study with chlorpromazine, the plasma neuroleptic level of haloperidol is not altered with aging and that parkinsonian symptoms induced by haloperidol occur simply in a plasma-neuroleptic-level-dependent manner.

In this issue

“…The radioreceptor assay was performed according to the procedure reported previously by Aoba et al . (1983, 1985). Caudates were dissected from calf brain at a local slaughter house and immediately placed in an ice‐cold 50 mM Tris–HCl buffer, pH 7.7.…”

The effect of age on the plasma levels of amoxapine and its major metabolite in depressed patients

“…One of these was for determining plasma amoxapine and 8-hydroxyamoxapine by GLC and the others were for plasma neuroleptic levels determination by RRA. RRA and the preparation of calf caudate receptor tissue were performed according to the technique of Cohen et al (1979) with a slight modification as reported elsewhere (Aoba et al, 1985). GLC method was performed using the technique of Cooper and Kelly (1979).…”

Neuroleptics in the treatment of psychosis in late life: A rational approach

“…However, given pharmacokinetic, pharmacodynamic, and other physiologic changes associated with ageing, the validity of such an extrapolation is unclear. Even with regard to dosage, the pharmacokinetic literature concerning elderly patients is scant: the neuroleptic level-dose (LD) ratio (equivalent to clearance at a steady state concentration) of haloperidol seems to be unchanged with age (Aoba et al, 1985), while the LD ratios of chlorpromazine (Aoba et al, 1987), perphenazine (Bolvig-Hansen and Larsen, 1985), remoxipride (Movin et al, 1990), thioridazine (Cohen and Sommer, 1988), and thiothixene (Yesavage et al, 1981) are significantly increased. Since no single traditional neuroleptic has proven to be more efficacious in the treatment of schizophrenia, the selection of a specific drug remains based on its side-effect profile (Young and Meyers, 1991).…”