Antipsychotic Polypharmacy in USA

Abstract

Fifty-six million prescriptions were dispensed for antipsychotics in the USA in 2010, at an estimated cost of $16.1 billion, and 90% of these were for atypical antipsychotics (IMS Institute for Healthcare Informatics: The use of medicines in the United States: review of 2010). Co-prescription of two (or more) antipsychotics or so-called polypharmacy is estimated from 2 to >50% depending on the population surveyed. Antipsychotic polypharmacy is of considerable importance from multiple perspectives such as its sheer volume, quality and safety of care, and cost. There is much variability in this practice based on age group, primary and co-morbid diagnoses, practice setting, health insurance status, etc. A thorough understanding of the associated factors is necessary to know what drives and maintains polypharmacy practice

Psychiatric, pharmacological and systems-of-care factors separately or together influence physician co-prescribing of two or more antipsychotics. Psychiatric factors include partial response to monotherapy, co-morbid psychiatric syndromes including behavioral challenges, and adverse effects or intolerance of high dose monotherapy, including but not limited to extra-pyramidal symptoms, metabolic effects and sedation. Pharmacological factors include variable receptor effects and pharmacokinetics. The third set of factors that sustains polypharmacy include the need to produce rapid clinical response, pressures of managed care, patient ­preferences and family concerns about specific symptoms and behaviors, the cross-titration trap, and the need to obtain treatment adherence.

This chapter describes the scope of antipsychotic polypharmacy in the USA in different clinical settings, and why clinicians find it necessary to prescribe multiple antipsychotics. We review the clinical and research evidence for and against ­antipsychotic polypharmacy and its practice in USA, and discuss the challenges confronting the patient, clinician, healthcare managers and policy makers. Cost of polypharmacy and interventional studies to change or reduce the practice of polypharmacy are also reviewed.

Antipsychotic polypharmacy will likely persist due to clinical necessity. Rather than pursue prescriptive, prohibitive, and/or regulatory approaches to complex patient management, it may be pragmatic to develop rational and cost-effective polypharmacy guidelines, and encourage translational research that will assist clinicians in cost-effective, evidence-based practices while meeting the unique needs of their patients.