Antidepressant Augmentation: A Review of the Literature and a Review of the Pharmacoeconomic Considerations.

Purpose: Antidepressant augmentation strategies for treatment-resistant depression (TRD) are discussed here with an analysis of patient out-of-pocket costs for various medications. The choice of agent ranges from newer atypical antipsychotics (aripiprazole, brexpiprazole, quetiapine) to older agents including buspirone, liothyronine (T3), and lithium. We sought to better understand the differences among these agents to aid in clinical decision making.

Methods: We conducted a focused review of the support for each of the aforementioned agents in antidepressant augmentation. We then compared the approximate out-of-pocket cost for each medication during a typical augmentation trial using the typical prescription costs on ClinCalc.com derived from the Medical Expenditure Panel Survey. We calculated the cost to achieve response for one patient with TRD based on the number needed to treat (NNT).

Findings: We observed significant variance in cost to achieve response based on the NNT derived from our review of each of the medications. For example, the overall out-of-pocket cost for one patient to achieve response with aripiprazole (the costliest generic agent) could cover lithium prescriptions for 4 to 5 patients with TRD to achieve response. Although brexpiprazole was estimated separately because of its brand name cost, we estimated that 324 patients receiving lithium could achieve response for same cost of single patient receiving brexpiprazole.

Implications: These findings suggest that among augmentation agents, there are differences in cost that may be highly important in clinical decision making. Other issues of medication monitoring may incur additional costs, and brand name medications offer significantly greater complexity and potential out-of-pocket costs to patients. The use of lithium as a first-line agent for TRD should be considered based on low cost, lowest NNT, and data in support of its efficacy.