Choice of generic versus brand-name antidepressants in a regulated prescription drug market: evidence from Taiwan.

Abstract A health care system in which there is no separation between prescription and dispensation, combined with a regulated prescription drug market, leads to various generic substitution mechanisms for antidepressants. We investigated the determinants of generic versus brand-name antidepressant choices in a regulated prescription market where physicians both prescribe and dispense drugs. Using data from a sample of one million individuals selected randomly from the registry of National Health Insurance beneficiaries in 2010, and all claims for these one million enrollees between January 1997 and December 2011, we employed logistic regression to examine the choice of generic versus brand-name antidepressants in the Taiwanese prescription drug market. Access to various antidepressant brands varies according to the accreditation level and type of ownership of the healthcare provider. Private healthcare providers and those with lower accreditation levels were more likely to prescribe generic antidepressants compared to their brand-name counterparts. The diversity of products and competition in the molecule market was positively associated with the probability of prescribing generic antidepressants. In a regulated prescription drug market with no separation between prescription and dispensation, the substitution of generic antidepressant prescriptions in place of brand-name prescriptions is likely driven by drug and provider market characteristics, rather than by lowering costs. The allocation of different types of ownership and accreditation levels of healthcare providers may lead to unequal access to various brands of antidepressants. Policies for improving the treatment of depression should take into account the structure of molecule and provider markets as important factors in determining the choice and utilization of antidepressants, in a healthcare system where physicians both prescribe and dispense drugs. Other psychotropic drug classes should be investigated to explore the effect of molecule and provider characteristics on the utilization of various classes of medication.