Even worse, according to two recent studies, the possibility of being told by the plan that you either can’t get an expensive brand-name drug because it’s not on its “formulary” list or will need prior authorization has grown significantly. 

And that can be bad for your health, considering that people with Medicare Part D plans take an average of four or five prescription drugs a month.

Branded medications often have Medicare restrictions

“When you’re talking about branded products, almost seven out of 10 have either some restriction or they’re excluded. That’s pretty high,” says Geoffrey Joyce, director of health policy at the USC Schaeffer Center, citing data from the March 2024 Health Affairs article he coauthored, “Medicare Part D Plans Greatly Increased Utilization Restrictions on Prescription Drugs, 2011–20.”

Joyce and his colleagues found that restrictions in Part D plans (what plans call “utilization management”) grew dramatically between 2011 and 2020 for both traditional Medicare and private insurers’ Medicare Advantage plans. In 2011, 21% of medications they reviewed had restrictions. In 2020, 44% did.

Sometimes, the plan’s list of covered medications (known as its formulary) didn’t include certain prescriptions. That was truer for traditional Medicare Part D plans than for Medicare Advantage Part D plans.

The three biggest pharmacy benefit managers excluded 1,356 medications for at least a year from 2019 to 2022, according to a Pembroke Consulting study.

Prior authorization, step therapy, and exclusions

Other times, beneficiaries needed to take a prescription similar to the one they wanted before they could get the one that they and their physicians preferred, a practice known as step therapy.

In many instances, people needed prior authorization: Their doctors had to prove to the Part D plan that the drug was medically necessary for them to get it covered.

Health insurers want to “steer patients and doctors toward what they think are lower-cost, more cost-effective therapies,” says Joyce. “So, in theory, it’s not necessarily bad.”

Formulary exclusions prevent “all but the few who successfully appeal or can afford to pay out-of-pocket from getting a restricted medication if it is prescribed by their physician,” the Health Affairs article said.

Zarek Brot-Goldberg, a University of Chicago public policy professor, says a 2023 National Bureau of Economic Research (NBER) study he and Harvard Medical School researchers conducted found that between one-fifth and one-quarter of all prescription drug spending from 2007 to 2015 required prior authorization.

Jumping through hoops

“If you take a really expensive drug, you’re going to have to go through prior authorization,” says Brot-Goldberg. “You would never want prior authorization for things like statins and beta blockers that are cheap and everyone should be getting. Those don’t have prior authorization that often.”

But some people do need expensive medications and “we’re making them jump through hoops,” he noted.

In Brot-Goldberg’s study, all the Part D plans had some degree of prior authorization, but each plan targeted different drugs.

More than 60% of primary care physicians surveyed by the Commonwealth Fund health research group said the amount of time they spend getting patients needed medications or treatments because of coverage restrictions is a “major” problem.

“You talk to doctors and they say, ‘I want the whole range’” of related medications to be available for my patients, says Joyce. “If drug A doesn’t work, I want to switch them to B and then C. But I’m not able to do that in a lot of these plans.”

Things could get worse in 2025

Leigh Purvis, the prescription drug policy principal at AARP, believes Medicare’s $2,000 annual out-of-pocket cap on prescriptions taking effect in 2025 could lead to more Part D plan prior authorization restrictions.

“I do think there’s a possibility that we could see plans changing their formularies and potentially becoming less generous because of the cost they’re facing” from the $2,000 cap, she says.

Already, many prescription drugs advertised on television—like Eliquis, Xarelto, Trulicity, and Enbrel—can cost Medicare beneficiaries thousands of dollars.

Prices for some of those medications have soared far more than the inflation rate.

A 2023 AARP Public Policy Institute report found that list prices for the top Medicare Part D drugs increased in price by an average of 226% since entering the market. The median price of new prescription drugs approved by the Food and Drug Administration tops $200,000.

The problem for low-income Medicare beneficiaries

The NBER paper found another Part D prior authorization problem among people eligible for Medicare’s low-income subsidy.

When those beneficiaries hadn’t signed up for a Part D plan and Medicare randomly assigned them a free version, the researchers discovered, half were required to get a different but related drug, and half were turned down for the prescription altogether.

But many low-income Medicare beneficiaries who learned at the pharmacy that they’d need prior authorization to get the similar drug never took steps to do so and wound up not taking any medication for their medical issue.

An inefficient system

“Prior authorization is not administered in what I would call the most efficient way,” says Brot-Goldberg. “What should happen is the patient should go back to their doctor and get them to submit a prior authorization request.”

Instead, he noted, they sometimes get discouraged and don’t bother.

“It’s puzzling because you’d think that many of these people have chronic diseases that doctors should be following up on,” Brot-Goldberg added. “Where are the doctors in all this, getting patients onto these drugs?”

Harm to Medicare patients

Exactly how much harm Part D prior authorization delays cause Medicare beneficiaries is hard to say, because data is scarce. “I don’t think we really have an idea of how bad this is,” says Brot-Goldberg.

In a 2022 American Medical Association survey, though, roughly a third of the 1,011 doctors polled said prior authorization led to a serious adverse event for a patient.

Joyce says that when he and his colleagues looked at people with Part D plans who were told they needed to take the generic blood thinner warfarin for Medicare coverage instead of pricier brand-name alternatives, “we showed some higher rates of stroke.”

Joyce’s research team is now studying whether patients with MS are facing health problems because they’re unable to get the drugs their doctors prescribed.

An October 2023 American Medical Association journal study found that roughly 15% of patients with cancer whose medication required prior authorization saw treatment delays of more than four weeks as a result; nearly 40% waited one to four weeks.

“Dealing with prior authorization issues adds an extra layer of stress, which is known to increase anxiety and can worsen treatment-related and disease-related symptoms and adverse effects,” the study authors wrote.

Frequent formulary changes

Part D prescription drug plans can, and do, change their formularies and prior authorization rules at any time. So, just because your Part D plan covers your expensive medication now doesn’t mean it will in the future.

“There are absolutely a lot of changes that take place from year to year,” says Purvis. That frustrates Medicare beneficiaries, Joyce noted.

The Biden administration has begun cracking down on prior authorization in Medicare Advantage plans, setting time limits on the delays. A few states have passed prior authorization laws exempting certain doctors in Medicare Advantage networks, too. Some large health insurers say they’re working to reduce prior authorization for Medicare beneficiaries.

In a small number of states, prescription drug affordability boards have tried to limit costs of certain medications, though pharmaceutical companies have challenged them.

Advice to avoid Part D prescription snags

So, what can people with Medicare Part D plans or those looking to enroll do to help ensure that the medications their doctors want them to take are covered?

Start by diving into Medicare’s online Plan Finder tool, which lets you see how each Part D plan works and compare alternatives.

“During Medicare Open Enrollment [generally Oct. 15 to Dec. 7], you really need to look at the Part D plans available to you and figure out whether the drugs you’re taking are subject to utilization management,” says Purvis. (People eligible for Medicare’s low-income subsidy can switch Part D plans anytime.)

Even if you have a Part D plan, study its latest documents online since the rules for what’s covered could be different than when you signed up.

When using Plan Finder, you’ll likely need to spend time unearthing the prior authorization rules and seeing which medications are on the plan’s formulary.

Brot-Goldberg did this last year for his father when he enrolled in Medicare for the first time.

“I avoided my dad facing prior authorization on one of his drugs,” says Brot-Goldberg.

But, he adds, doing the research for this was hard. “And I’m an expert.” He’ll go through the process again for his mother next month.

You might also call your State Health Insurance Assistance Program, known as a SHIP. Here, knowledgeable staffers and volunteers can answer your Medicare questions and guide you through the Part D puzzle.

The Part D appeals process

If your Part D plan denies you coverage for a medication, you can try to appeal.

The process can be cumbersome and exhausting, but it could lead to a reversal.

“They string you along and make it hard,” says Joyce. You need to make a stronger medical case than just saying your doctor wanted you to take the drug, he notes.