Trends in Canadian prescription drug purchasing: 2001–2020

BACKGROUND: In 2019, more than $34.5 billion was spent on prescription drugs in Canada. However, little is known about the distribution of this spending across medications and settings (outpatient and inpatient) over time. The objective of this paper is to describe the largest expenditures by medication class over time in inpatient and outpatient settings. This information can help to guide policies to control prescription medication expenditures. METHODS: IQVIA’s Canadian Drugstore and Hospital Purchases Audit data from January 1, 2001, to December 31, 2020, were used. In this dataset, purchasing was stratified by outpatient drugstore and inpatient hospital. Spending trajectories in both settings were compared to total expenditure over time. Total expenditure of the 25 medications with the largest expenditure were compared over time, stratified by setting. Nominal costs were used for all analysis. RESULTS: In 2001, spending in the outpatient and inpatient settings was greatest on atorvastatin ($467.0 million) and erythropoietin alpha ($91.2 million), respectively. In 2020, spending was greatest on infliximab at $1.2 billion (outpatient) and pembrolizumab at $361.6 million (inpatient). Annual outpatient spending, although increasing, has been growing at a slower rate (5.3%) than inpatient spending (7.0%). In both settings, spending for the top 25 medications has become increasingly concentrated on biologic agents, with a reduction in the diversity of therapeutic classes of agents over time. DISCUSSION: Identification of the concentration on spending on biologic agents is a key step in managing costs of prescription medications in Canada. Given the increases in spending on biologic agents over the last 20 years, current cost-control mechanisms may be insufficient. Future research efforts should focus on examining the effectiveness of current cost-control mechanisms and identifying new approaches to cost control for biologic agents. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s40545-022-00420-4.