Nearly a Third of Single-Source Drug Prescriptions Are Rejected at the US Pharmacy Counter

You hand over a new prescription, wait a few polite minutes, and then the pharmacist looks up with an apologetic expression. Your insurer has declined it. Not “come back later” or “we need a signature,” but a flat electronic denial that arrives before the pill bottle is even filled.

This happens more often than many would assume. According to a new analysis of American pharmacy claims, it’s happening a lot more frequently than it used to.

These findings come from a study published on July 9 in JAMA. The numbers are surprising. Between 2018 and 2024, approximately one in three initial attempts to fill a branded, single-source drug in the US was denied on the spot.

Joseph Levy at the Johns Hopkins Bloomberg School of Public Health and his team examined a database most of us never think about: the electronic exchanges between pharmacies, insurers, and the clearinghouses that connect them. Their source, IQVIA’s Formulary Impact Analyzer, includes about 57 percent of all US pharmacy claims. The team analyzed a 10 percent sample covering around 1.17 million people and two million initial fill attempts. Each of these attempts marked the moment a prescription met a formulary. The results showed that this moment increasingly ends in rejection.

Overall, 68 percent of those first attempts were paid immediately. The remaining were categorized into two types of denials. About 14.8 percent were turned down because the branded drug prescription was simply not on the insurer’s list. The other 17.2 percent faced what the industry calls utilization management: prior authorization, step therapy, and the paperwork a patient or doctor must navigate before coverage starts.

The paperwork wall keeps getting higher.

Most of the growth is found in the second category. Formulary-based rejections as a whole increased by 67.4 percent during the study period, from 24.3 percent of attempts in 2018 to 40.7 percent in 2024. Much of this increase did not come from insurers removing drugs from their lists outright. Instead, it resulted from more hurdles for drugs that, on paper, are covered. Among individuals with commercial insurance, utilization-management denials jumped from 13.3 percent to 32.4 percent. For Medicaid managed care, they rose from 15.4 percent to a striking 41.7 percent.

Where you get your coverage matters greatly in this context. Someone on a marketplace exchange plan or in Medicaid managed care faced rejection about half the time (48.7 and 49.8 percent respectively), while Medicare Advantage drug plans denied under a fifth of first attempts. Same prescriptions, vastly different chances, depending on the fine print of a plan most patients chose while looking at a comparison table.

The type of drug also tells a story. Diabetes GLP-1 agonists, which include some of the most talked-about medications of the decade, were rejected 35 percent of the time. The weight-loss incretin products in the same general area fared worse: an astonishing 85.1 percent of first attempts were denied. Direct-acting blood thinners, on the other hand, passed through successfully, with over 90 percent paid on the first try. If you want to understand where the cost battles are occurring in American medicine, the rejection rates highlight the path.

What happens after the denial?

This aspect reveals a more serious issue. Levy’s team tracked each rejected prescription for 90 days to see its outcome. It turns out getting turned away isn’t just a detour; it often leads to a dead end. Of the prescriptions initially denied, 38.6 percent eventually reached the patient as the original drug. Another 13 percent arrived as a substitute in the same therapeutic class. However, nearly half, 48.4 percent, went nowhere at all: no original drug, no equivalent, and nothing else in the same class within three months.

For those who eventually received treatment, the wait averaged 12.2 days. This isn’t a major delay for a mild condition, but it can be significant for someone who needs a medication their doctor considers urgent. The authors point out what they cannot determine. A patient denied one drug may have sensibly started another from a different class entirely, which their strict definition wouldn’t capture. Subsequent health outcomes are beyond the scope of this data. What the study measures is access; it’s simply about whether the prescribed drug or a similar one ever made it to the patient.

Looking at every attempt within the sample, the overall picture becomes clear. About 15.5 percent of individuals, nearly one in six, left the pharmacy without receiving either the drug or a similar alternative within the following 90 days. This share more than doubled over the study period for those on commercial, exchange, and Medicare Part D plans. The authors depict the situation as a trade-off instead of a villain’s story. These tools are known to reduce spending, and insurers argue they guide patients toward more affordable, equally effective options while maintaining leverage to negotiate discounts. Yet, the flip side, as this study starkly indicates, includes delayed care, abandoned care, and mounting administrative barriers that hit at the pharmacy counter rather than at the doctor’s office.

Rejections typically occur not when the prescription is written, but when it is filled. This means doctors often prescribe drugs that their patients’ plans won’t easily cover, unaware until the pharmacist informs them. The authors suggest making coverage rules clear at the moment of prescribing, which could prevent many of these avoidable denials from happening. Whether it’s possible to achieve this in a system with numerous payers and complex rules is another question. For now, the pharmacy counter remains the place where the cost struggle in American medicine is settled, one apologetic pharmacist at a time.

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