Background: Controversy exists over the true therapeutic equivalence of branded and generic levothyroxine-the drug of choice for treating hypothyroidism-so professional societies recommend against switching between different formulations of the drug and suggest that patients who do switch be monitored. Payers typically encourage switching to generic drugs because of lower drug acquisition costs.
Objective: To evaluate the impact of switching levothyroxine formulations on actual healthcare costs.
Methods: Patients with hypothyroidism and at least 6 months of branded levothyroxine therapy were identified from a large healthcare claims database. Patients who subsequently switched to another levothyroxine formulation and could be followed for 6 months postswitch were matched to demographically similar patients who were continuous users of branded levothyroxine. Pre- and postswitch healthcare costs for each group were compared.
Results: The savings in prescription drug costs after switching from branded to generic levothyroxine are offset by increases in costs for other healthcare services, such that switching is actually associated with an increase, not a decrease, in total healthcare costs.
Conclusion: In the absence of cost-savings, there is no clear rationale for switching patients from brand to generic levothyroxine.