Pharmacokinetics in geriatric psychiatry

A population approach to characterise amisulpride pharmacokinetics in older people and Alzheimer's disease

INTRODUCTION

Current prescribing guidelines for the antipsychotic amisulpride are based largely on pharmacokinetic (PK) studies in young adults, and there is a relative absence of data on older patients, who are at greatest risk of developing adverse events.

METHODS

This study aimed to develop a population PK model for amisulpride specifically in older people, by combining data from a richly sampled phase 1, single (50 mg) dose study in healthy older people (n = 20, 65-79 years), with a clinical dataset obtained during off label, low-dose (25-75 mg daily) amisulpride prescribing in older people with Alzheimer's disease (AD) (n = 25, 69-92 years), as part of an observational study.

RESULTS

After introducing a scaling factor based on body weight, age accounted for 20 % of the inter-individual variability in drug clearance (CL), resulting in a 54 % difference in CL between those aged 65 and those aged 85 years, and higher blood concentrations in older patients.

DISCUSSION

These findings argue for the consideration of age and weight-based dose stratification to optimise amisulpride prescribing in older people, particularly in those aged 85 years and above.

rTMS for pharmacoresistant major depression in the clinical setting of a psychiatric hospital: effectiveness and effects of age

BACKGROUND

Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive method of brain stimulation used in the treatment of drug-resistant major depressive disorder (MDD). It has been suggested that the efficacy of rTMS decreases with the age of the patient, but the data are contradictory. Here, we analyze in our clinical setting the efficacy of a 3-week rTMS treatment in drug-resistant MDD during a 3 month period and the potential influence of age on this efficacy.

METHODS

Stimulation consisted of 15 sessions of rTMS over the dorsolateral prefrontal cortex. Clinical evaluations included the Hamilton Depression Rating Scale (HDRS), and the Beck Depression Inventory (BDI) at baseline, after 3 weeks of treatment, and 1 month and 3 months after the last session.

RESULTS

Data from 93 patients issued from the 178 patients active file were analyzed. The antidepressant effect observed in the two age groups (<65 and ≥65) did not differ at the end of the treatment and 3 months later, with a comparable number of responders (50% decrease in HDRS score from baseline) (53.3% for age <65 versus 46.7% for age ≥65, p=0.51). The treatment had a significant effect over time. We found no evidence of the age affecting outcome at 3 months after the last session.

LIMITATIONS

Previous antidepressant treatments, and therapeutic drug use modifications after rTMS treatment, degree of pharmaco-resistance or duration of current episode are not reported.

CONCLUSION

RTMS of the DFPLC is effective as an add-on treatment for cases of pharmacologically refractory major depression, independent of the patient age.