American College of Physicians: Internal Medicine — Doctors for Adults ®


Drug switching: lowering costs vs. adverse interactions, potential errors

From the July/August 2000 ACP-ASIM Observer, copyright 2000 by the American College of Physicians-American Society of Internal Medicine.

By Deborah Gesensway

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One day this spring, the fax machine at the Jacksonville, Fla., office of endocrinologist Yank D. Coble Jr., MACP, was particularly busy. It spewed forth letters from a health plan's pharmacy benefit manager (PBM) asking the doctor to switch six osteoporosis patients from Fosamax to another drug.

Dr. Coble dutifully had his office manager pull the patients' charts and reviewed them, "just to make sure there wasn't something that had escaped me." He soon realized, however, that the PBM was suggesting the voluntary switch not for clinical reasons, but because it was getting a special deal on the replacement drug and would save money if physicians like Dr. Coble switched their patients to it.

Dr. Coble did not switch his patients to the new drug, in part because he had questions about how well the alternative drug would work for these particular patients and whether it could produce troublesome side effects. Perhaps even more importantly, he said, he was not inclined to switch patients from a drug that was working simply to help improve the bottom line of a drug distribution firm. "We all want to be as cost-effective as we can be," he explained, "but the most important thing is to have the right medication and the right continuity of that medication."

More and more, however, physicians like Dr. Coble are under growing pressure to change how they prescribe drugs. As health plans try to stem double-digit increases in drug costs, many are relying on drug switching schemes, also known as therapeutic interchange or substitution.

While many physicians say they see drug switching as just one more exasperating part of managed care, the issue has more serious implications. Critics worry that as patients are switched from drug to drug in larger numbers, the number of adverse interactions and prescription-writing errors will rise. There are also concerns about the financial incentives behind drug switches and how those incentives are affecting health care's bottom line.

As lobbying over proposals to enact a Medicare drug benefit heats up, drug switching is poised to attract even more attention. Medicare drug benefit proposals from both Republicans and Democrats would allow PBMs to manage benefits and use formularies, a move that critics say will surely lead to even more drug switching. That has worried some because drug switching raises particularly troubling issues in elderly populations.

A growth industry

Drug switching takes a variety of forms. Frequently, pharmacists paid by PBMs call physicians and behave much like telemarketers trying to "move market share." In other cases, patients themselves initiate a switch after a pharmacist tells them their co-pay will go up if they don't switch. Although most switches require a doctor's sign-off, patients' medications are sometimes changed without warning.

Despite their growing use, drug-switching programs have never been studied to determine the effects on quality of care, potential adverse clinical outcomes, patient and physician satisfaction or even costs, according to a paper in the March/April issue of the health policy journal Health Affairs. Moreover, PBMs have attracted the attention of everyone from consumer advocates to government regulators, who are concerned that the companies' practices may represent fraud or abuse.

Part of the problem is that PBMs often solicit payments from drug manufacturers and wholesalers in return for switching patients to their products. James G. Sheehan, JD, the assistant U.S. Attorney based in Philadelphia, is heading an ongoing investigation examining whether those financial incentives amount to kickbacks. Last year, his office subpoenaed documents from PBMs and drug manufacturers to examine the financial incentives used in drug-switching schemes.

According to Mr. Sheehan, doctors tend to see drug-switching programs as just one more managed care hassle, and most simply don't have the time or energy to serve as an adequate check on the system. "The doctors are being buried in faxes and telephone calls from people who know nothing about the patients saying they want the doctors to switch their drugs," he said. "Some of the calls are misleading, either representing a drug as not covered when in fact it is, or misrepresenting information the company has about a patient's condition."

Supporters of drug switching are quick to point out that for the vast majority of patients, switching from one drug to another within the same class creates few problems. For some, it may actually prompt physicians to prescribe a better and cheaper drug that they may have otherwise overlooked.


But for some patients, results of the switch range from annoying to life-threatening. While physicians often know which patients won't be able to handle a different drug--certain H2 blockers, for instance, are contraindicated for patients with liver problems--that's not always the case.

First, all drugs within a therapeutic class aren't always the same. "Antidepressants are a good example," explained Jerry Avorn, MD, associate professor of medicine at Harvard Medical School and chief of the division of pharmacoepidemiology and pharmacoeconomics at the Brigham and Women's Hospital in Boston. "There is certainly anecdotal evidence that a patient who does well on Prozac will not necessarily do as well on Zoloft." Making matters worse, he said, is that no one is really sure how many milligrams of Prozac equals how much Zoloft.

Even when scientists agree that drugs within a therapeutic class are equivalent, patient confusion can lead to problems with compliance. That factor alone makes some clinicians wary of switching drugs even within the same therapeutic class.

"Switching is very confusing to the patient," explained Paul A. Dolinsky, FACP, a general internist in West Hartford, Conn. "Which drug are we stopping? Which drug are we starting? If patients are on six different medicines, they sometimes end up taking two very similar medicines because they never stopped taking one medicine when we supposedly switched them to a substitute."

Patients aren't the only ones who find drug switching confusing. Lawrence L. Faltz, FACP, a rheumatologist in Sleepy Hollow, N.Y., and the College's Interim Governor for New York Hudson Valley Chapter, said he finds therapeutic substitution programs disturbing because they increase the odds that someone will make a mistake. "I don't have an infinite brain," he said. "I always prefer to not have to memorize the dosages of lots of different drugs, especially in classes that I don't use on a regular basis."

Drug interactions are another concern. "One of the things drug switching does is completely sabotage your attempt to manage drug interactions," said David Trachtenberg, MD, a psychiatrist in Bethesda, Md. "For example, if somebody is on erythromycin and I give them a certain antidepressant, they can get blood levels far beyond what I intended."

"When drug companies go to the FDA for permission to market a new antidepressant, for example, they go to great lengths to prove that it should be approved because it is so different from other drugs out there," Dr. Trachtenberg said. "But then they put the same drug into the formulary and make an about-face and say all the drugs in one class are the same. Well, they are not."

Problems in the elderly

These concerns are only heightened when it comes to the elderly, for whom drug switching has even more potential for harm. Frail elderly people tend to have more comorbidities and often are being treated by numerous physicians. They can also be more disconcerted by changes in pill color, shape or packaging and they often have a physiological make-up that causes different formulations to work differently for them.

"In an elderly person, all bets are off," said David B. Nash, FACP, associate dean and director of the office of health policy and clinical outcomes at Thomas Jefferson University Hospital in Philadelphia. Co-author of a recent report entitled "Why the Elderly Need Individualized Pharmaceutical Care," Dr. Nash said policy-makers need to pay attention to the switching issue as they debate a Medicare drug benefit. "Anybody can write a formulary, but doing it for the elderly is a little bit more complicated," he said.

In part because of such concerns, the College says that any Medicare prescription drug benefit must include consumer protections, "particularly if the benefit is to be restricted by a formulary or administered by a PBM." (For more information on the College's policy positions, go to

One switching program that some researchers say might ease some concerns about complications, particularly in the elderly, is being used in the Canadian province of British Columbia. The program uses "reference pricing," where the government selects a drug in each therapeutic class; it then agrees to pay the full cost, or the reference price, of that drug. The government is hoping that manufacturers will price competing drugs to match the reference price, or that patients will switch to lower-priced drugs to avoid co-pays for their medications.

Sebastian Schneeweiss, MD, instructor in medicine at Harvard Medical School, has been studying the new program. He said that one early lesson is that to reduce--or eliminate--clinical complications caused by therapeutic substitutions, clinicians who suspect a problem must have an easy way to opt out.

"British Columbia had very generous exemption rules," he explained. "A physician only had to fax a form that said the patient was frail and elderly and needed the more expensive medication. In 95% of the cases, the benefits plan approved it. If you are convinced that these drugs really are equivalent, you don't need exception rules, but we often don't have the science to prove that."

Concerns about cost

While drug switching theoretically helps cut health care costs, there are lingering concerns that it may actually do just the opposite. Some critics, like Mr. Sheehan of the U.S. Attorney's office, charge that most of the money saved from switching to cheaper drugs isn't being passed back to health plans--and to consumers in the form of lower health insurance premiums. Instead, critics say, any savings are being kept by benefit management companies.

Physicians say they have seen direct evidence that drug switching can actually raise overall costs. Dr. Dolinsky, for example, the general internist from West Hartford, said that when patients are confused about a new drug they have been switched to, they typically make another office visit, which consumes health care resources--and may generate another co-pay for the patient. "And if it's a drug to lower cholesterol," he added, "you want to make sure that the new product is working, so you have to do more laboratory testing and follow-up."

In addition, Mr. Sheehan said, some critics suspect that switches sometimes occur from less expensive to more expensive drugs, because manufacturers offer PBMs rebates to designate their products "preferred" drugs in the PBMs' formularies. "Sometimes, if the drugs are not more expensive now, they will be next year after the patent expires on the older drug," he said. (Mr. Sheehan urges any physician with comments on the practice to contact him at

For physicians like Dr. Faltz from New York, the bottom line isn't one of costs, but responsibility. "This scheme is just one more example of physicians losing their authority while still having all the responsibility," he said. "As a physician, you are responsible for the outcome. If the patient doesn't have a good response, you are the one in court."

Deborah Gesensway is a freelance writer in Glenside, Pa.

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