Insurance denials for first-time prescriptions of brand-name drugs with no generic alternative jumped 67% between 2018 and 2024, according to a new study published in JAMA.
Nearly half of patients whose prescriptions were initially denied never filled either the prescribed medication or a similar drug within 90 days, raising concerns about delayed or foregone treatment.
Researchers say growing use of prior authorization, step therapy and formulary exclusions is the primary driver of the increase, reflecting insurers' efforts to control soaring prescription drug costs.
Americans prescribed brand-name medications without generic alternatives are increasingly running into insurance roadblocks at the pharmacy counter. A newly published study found that denial rates rose dramatically between 2018 and 2024.
The study, led by researchers at the Johns Hopkins Bloomberg School of Public Health and the American Enterprise Institute and published in the Journal of the American Medical Association (JAMA), analyzed more than 2 million first-time prescription fill attempts across commercial insurance, Medicare, Medicaid and Affordable Care Act marketplace plans.
Researchers found that insurers rejected 40.7% of initial attempts to fill brand-name prescriptions in 2024, up from 24.3% in 2018—a 67% increase.
The consequences often extended beyond a temporary inconvenience. Among patients whose prescriptions were initially denied, 48.4% did not fill either the prescribed medication or another drug in the same therapeutic class within 90 days. Those who ultimately obtained treatment waited an average of 12 days after the initial rejection.
"We found that insurance restrictions are increasingly shaping whether and when patients receive medications their clinicians prescribe," lead author Joseph Levy, an assistant professor in the Bloomberg School's Department of Health Policy and Management, said in a statement.
"While these policies may help control drug spending, they can also create meaningful barriers to timely treatment and place growing administrative burdens on patients, pharmacists, and clinicians."
Prior authorization a growing hurdle
About one-third of all initial prescription attempts were rejected because of formulary exclusions or utilization management policies, such as prior authorization requirements or step therapy, which require patients to try less expensive medications before insurers will cover the prescribed drug.
The researchers concluded that the growing use of these utilization management tools accounted for most of the increase in denials during the study period. Commercial insurance plans and Medicaid managed care plans experienced some of the largest increases in these restrictions.
Denial rates also varied significantly by drug category. Medications in the incretin class—including GLP-1 weight-loss drugs—had the highest rejection rate at 85%, while oral anticoagulants had one of the lowest rates at 6.7%.
Marketplace plans and Medicaid managed care plans posted the highest overall denial rates, with nearly half of all first-time prescription attempts rejected. Medicare plans generally had lower rejection rates.
Balancing access and costs
The study comes as insurers face mounting pressure to manage spending on expensive brand-name drugs, particularly specialty medications and newer therapies that can cost thousands of dollars per month.
According to the Association for Accessible Medicines, cited by the researchers, brand-name drugs accounted for only about 10% of prescriptions filled in 2024 but represented 88% of total prescription drug spending—about $700 billion. By contrast, generic drugs and biosimilars made up roughly 90% of prescriptions while accounting for only 12% of spending.
The researchers acknowledged that utilization management can help insurers negotiate lower prices and encourage cost-effective prescribing. However, they suggested that simplifying and standardizing prior authorization requirements, along with providing clinicians with real-time information about insurance coverage, could reduce unnecessary delays in treatment while preserving insurers' ability to manage costs.