A pharmacoeconomic model for making value-based decisions about serotonin reuptake inhibitors

Managed care organizations and pharmacy benefit managers often use tiered formularies to contain drug costs. Cost is one factor used to decide tier placement. Drug prices alone may not reflect the true cost of using particular drugs within a class. A decision-analytic model of the serotonin reuptake inhibitor (SRI) class of antidepressants was reviewed. SRIs include selective serotonin reuptake inhibitors (SSRIs) and serotonin and norepinephrine reuptake inhibitors (SNRIs). The model uses rates of adverse drug reactions (ADRs) and discontinuation rates found in the products' prescribing information, along with other probabilities derived from the literature. The model estimates the overall direct medical costs and cost-effectiveness of SRIs in a managed care setting, taking into account the medical consequences of treatment-emergent ADRs. This paper discusses the context in which the model was constructed and its strengths and weaknesses as a tool for pharmacy and therapeutics (P&T) committees that are faced with the challenge of evaluating new and current drugs in this class.