January 10, 2011
(Ivanhoe Newswire) -- Top-selling drugs, known as atypical antipsychotic medications, lack evidence that they'll actually be beneficial, according to a new study. Drugs in this class may cause serious effects such as weight gain, diabetes, and heart disease, along with costing Americans billions of dollars.
"Because these drugs have safety issues, physicians should prescribe them only when they are sure patients will get substantial benefits," Randall Stafford, M.D., Ph.D., associate professor of medicine at the Stanford Prevention Research Center and senior author of the study, was quoted as saying. "These are commonly used and very expensive drugs."Prescriptions for these drugs have risen steadily since they first came on the U.S. market in 1989. The U.S. government's original stamp of approval for the new drugs was for treating schizophrenia, but they're used more today for other conditions, including other psychoses, autism, bipolar disorder, delirium, dementia, depression and personality disorders. Some of these uses have recently been approved by the U.S. Food and Drug Administration but many have not.
These drugs' cost represented the largest expenditure for any single drug class in 2008 -- accounting for nearly 5 percent of all drug spending. According to a 2004 study, a quarter of all residents of U.S. nursing homes had taken them. Some of these drugs include quetiapine, aripiprazole (brand name, Abilify), olanzapine (Zyprexa) and risperidone (Risperdal). Each of these has annual U.S. sales exceeding $1 billion.
"Most people think, 'If my doctor prescribed this, the FDA must have evaluated whether this drug was safe and effective for this use.' That's not true," said Dr. Stafford. When doctors prescribe drugs for purposes other than those approved by the FDA, it's called "off-label" use.
Though it's riskier for patients, there's nothing illegal about it, and can make sense medically in some instances, Stafford said, especially if there are no approved treatments or if a patient has not responded to approved drugs.
The researchers analyzed the results of a physician survey conducted by the health care information company IMS Health. About 1,800 physicians participated each calendar quarter, and each was randomly assigned two days per quarter to provide data.
After finding out which antipsychotics were being used, and for what purpose, the researchers assessed the strength of the evidence supporting those that lacked FDA approval using efficacy ratings from the widely-used drug compendium, Drugdex.
They found that antipsychotic treatment prescribed during the surveyed doctors' visits nearly tripled from 6.2 million in 1995 to 16.7 million in 2008 (the most recent year for which they had data). During this period, prescriptions for first-generation antipsychotics decreased from 5.2 million to 1 million. Antipsychotic use for indications that lacked FDA approval by the end of 2008 increased from 4.4 million prescriptions during surveyed doctors' visits in 1995 to 9 million in 2008. In 2008, more than half (54 percent) of the surveyed prescriptions for the new-generation antipsychotics had uncertain evidence. An estimated $6 billion was spent in 2008 on off-label use of antipsychotic medication nationwide, of which $5.4 billion was for uses with uncertain evidence. Prescriptions for antipsychotics began dropping slightly in 2006, shortly after the FDA issued a warning about their safety.
Stafford suggests the upswing in prescriptions for antipsychotics despite the absence of good evidence for their value in many instances is the result of marketing, whether legal or illegal, and ingrained cultural tendencies. "Physicians want to prescribe and use the latest therapies, and even when those latest therapies don't necessarily offer a big advantage, there's still a tendency to think that the newest drugs must be better," Stafford said.
SOURCE: Pharmacoepidemiology and Drug Safety, published online January 7, 2010