Prevalence of concomitant oral antipsychotic drug use among patients treated with long-acting, intramuscular, antipsychotic medications.

OBJECTIVE

Long-acting injectable (LAI) antipsychotic drugs are viewed as monotherapeutic alternatives to oral medications to promote medication adherence, but there have been no descriptive studies of concomitant use of oral and LAI medications.

METHODS

A list of all patients receiving services from the Connecticut Mental Health Center from July 1, 2009, to June 30, 2010, was obtained from center administrative records, and those carrying an initial intake diagnosis of schizophrenia or schizoaffective disorder were identified. All team leaders were approached, and all clinicians were asked to identify patients on their case load prescribed LAIs during the time interval above. Also, all internal and external pharmacy orders were reviewed. Concomitancy was defined as simultaneous oral and LAI antipsychotic use at any time from July 1, 2009, to June 30, 2010. Data were culled from the medical records using a form (available on request) that recorded current LAI antipsychotic, reasons for LAI use, length of time on LAI, monthly dosage, and all concomitant oral antipsychotics, antidepressants, and anxiolytic agents.

RESULTS

Among 124 patients on LAI medications, 57 (46%) received concomitant oral and LAI antipsychotics: 27 (47%) were prescribed LAI haloperidol, 19 (33%) LAI fluphenazine, and 11 (19%) risperidone microspheres. Logistic regression showed greater use of oral antipsychotic for both Hispanic ethnicity (odds ratio, 3.8; 95% confidence interval, 1.3-10.8) and alcohol abuse/dependence (odds ratio, 6.5; 95% confidence interval, 1.3-31.9), with no significant differences on other variables. There were no significant differences between LAI agents in rates of use of concomitant oral antipsychotic, anticholinergic, sedative/hypnotic, or mood stabilizer. Patients were more likely to be prescribed concomitant oral preparations of their LAI agent than another oral antipsychotic. Higher dosing of LAI treatments was associated with a significantly greater likelihood of use of oral psychotropics and anticholinergics.

CONCLUSIONS

Almost one half of patients prescribed LAI antipsychotics receive oral antipsychotics and other oral psychotropics. This challenges the notion that LAIs are used as monotherapy in real-world settings. Concomitant oral and LAI antipsychotic prescriptions may represent a common practice of polypharmacy that merits further investigation.