Objectives: To investigate the relationship between patient age and the selection and dosage of antipsychotic drugs (APDs) for treatment of schizophrenia. We describe age effects for multiple individual APDs, thus allowing comparisons between drugs.
Methods: Prescription data of 32,062 inpatients with schizophrenia from 2000 to 2017 were obtained from the Drug Safety Program in Psychiatry (AMSP) database. APD selection and dosage were related to patient age with sex as an influencing variable. Moreover, a systematic search of current guideline recommendations on APD treatment in patients with schizophrenia aged ≥65 years was performed.
Results: Eighty percentof elderly patients (≥65 years) received a second-generation APD, most commonly risperidone. The dosage of APDs increased with age until about age 40 years, then decreased slowly at first and more steeply beyond age 55 years. The influence of age as well as sex on dosage partly differed between the individual drugs. Only one of eight schizophrenia guidelines systematically addressed specific aspects of pharmacotherapy in older adults.
Conclusions: In clinical routine, age has a significant impact on selection and dosing of APDs. Information on optimising pharmacotherapy in older adults with schizophrenia from clinical trials is needed. Guidelines should be improved regarding APD therapy specifically for older adults.
Keywords: Antipsychotic drugs; drug dosage; elderly; geriatric psychiatry; schizophrenia.