Drug Switching Raises Risks

Changes Prescribed by Drug Plans Have Side Effects

Medically Reviewed by Gary D. Vogin, MD
From the WebMD Archives


July 19, 2002 -- Switching from one medication to another, less expensive one due to prescription drug plan restrictions may produce some unwanted side effects, especially for older Americans. A new survey shows that more than one in five American adults over 50 have been prescribed or switched to a lower cost substitute, but 13% of them said the new drug was ineffective in treating their condition.

The survey, commissioned by Project Patient Care and conducted by Harris Interactive, suggests that drug plan formularies may have a negative impact on the health of Americans who rely on prescription drugs.

Formularies are lists of prescription drugs that are covered on more favorable terms for the enrollee than other drugs. If a person is prescribed a drug that is not on the formulary list, he or she will often have to pay significantly more for the drug. A drug substitution or switch occurs when a doctor, or a pharmacist in consultation with the doctor, chooses a similar drug from the formulary list to avoid additional costs to the patient.


But the survey found that these drug switches actually wind up costing the patients an average of $58.50 per person in additional out-of-pocket costs related to higher drug costs or additional medical follow-up. And of the estimated 9 million adults over 50 who were given a formulary substitution, 22% said they experienced side effects from the new medication.

Some of those side effects can be serious. For example, 14% of those who said they experienced more than minor side effects from a drug formulary substitution had to visit an emergency room due to the drug switch, and 11% had to be hospitalized.

Marilyn Moon, a health policy expert at the Urban Institute, says the survey is important because it questions the practice of judging the success of prescription benefit plans by how efficiently they curb costs.

"The genuine belief that people think healthcare is just a business, and you can just substitute one drug for another is called into question by this study," says Moon. "It's important to not assume that all statins [a group of cholesterol-lowering drugs] are the same, and that all drugs in same class will have the same effect."


David Chess, MD, founder and chairman of the nonprofit patient advocacy group that initiated the survey, Project Patient Care, says a separate survey also looked at doctor's attitudes about drug formularies and found striking similarities.

"A remarkable 23% of physicians thought the formularies were hazardous to people's health," says Chess. More than three-fourths of the healthcare providers surveyed said they should be the ones to decide which medications to prescribe their patients.

More than a third of the healthcare providers said they consider the patient's drug coverage when choosing a prescription medication and that the patient's ability to pay has a strong impact on what medications are prescribed.

Chess says the additional hassle and risks associated with drug formularies are having a negative effect on how both patients and doctors view the healthcare system as a whole. He says the drug substitutions that seem to save a few dollars for the benefit plans eventually end up adding to rising healthcare costs in other ways that put the patient's health at risk.

"The more medications a person is on, the more likely the person will get in trouble if there is a switch," Chess tells WebMD. "If a drug is not a preferred drug, chances are that there's good reason why."