Adverse Drug Effects On the Rise

Increase Is 'Cause for Alarm,' Researchers Say

By Kathleen Doheny
WebMD Health News

Reviewed by Louise Chang, MD

September 10, 2007 - Reports of adverse drug effects reported to the U.S. Food and Drug Administration (FDA) more than doubled in the last decade, according to a new study. Deaths associated with the serious effects also more than doubled.

"A change of this magnitude ought to be cause for alarm," says Thomas J. Moore, senior scientist, drug safety and policy, for the Institute for Safe Medication Practices in Huntingdon Valley, Pa., and the lead author of the study.

Moore and his colleagues analyzed serious adverse drug events voluntarily reported to the FDA though the Adverse Events Reporting System (AERS), known as the "MedWatch" reports, from 1998 to 2005. A serious adverse drug event is defined as one that results in death, a birth defect, disability, hospitalization, was life-threatening, or needed intervention to avoid harm.

The "hit list" of drugs often associated with adverse side effects includes the over-the-counter pain reliever acetaminophen (Tylenol) as well as insulin, the antidepressant paroxetine (Paxil), the anti-inflammatory drug celecoxib (Celebrex), and the painkiller fentanyl.

The report is published in the Sept. 10 issue of the Archives of Internal Medicine.

In all, 467,809 serious adverse events were reported during the years 1998 to 2005. But annually, the number of reports rose 2.6-fold from the years 1998 to 2005, Moore found. In 1998, 34,966 adverse events were reported, but by 2005, the number had grown to 89,842.

Fatalities from adverse drug events rose from 5,519 in 1998 to 15,107, a 2.7-fold increase.

The Drug List

On the list of drugs most commonly identified in fatal events:

  1. Oxycodone (OxyContin and others)
  2. Fentanyl (Duragesic and others)
  3. Clozapine (Clozaril)
  4. Morphine
  5. Acetaminophen (Tylenol)
  6. Methadone
  7. Infliximab (Remicade)
  8. Interferon beta (Rebif, Betaseron, Avonex)
  9. Risperidone (Risperdal)
  10. Etanercept (Enbrel)
  11. Paclitaxel (Taxol)
  12. Acetaminophen-hydrocodone (Vicodin, Lortab, and others)
  13. Olanzapine (Zyprexa)
  14. Rofecoxib (Vioxx)*
  15. Paroxetine (Paxil)

Drugs on the list of those most commonly identified in disability or serious outcomes:

  1. Estrogens
  2. Insulin
  3. Infliximab (Remicade)
  4. Interferon beta (Rebif, Betaseron, Avonex)
  5. Paroxetine (Paxil)
  6. Rofecoxib (Vioxx)*
  7. Warfarin (Coumadin)
  8. Atorvastatin (Lipitor)
  9. Etanercept (Enbrel)
  10. Celecoxib (Celebrex)
  11. Phentermine (Pro-Fast)
  12. Clozapine (Clozaril)
  13. Interferon alfa (Alferon N, Infergen, Intron A, Roferon-A)
  14. Simvastatin (Zocor)
  15. Venlafaxine (Effexor)

* This drug is no longer available in the U.S.

What the Numbers Mean

"We are losing substantial amounts of ground in protecting people against serious injury and death from prescription drugs," Moore says. The rise in reports, he says, can't be explained by the fact that doctors are more willing to report adverse events under the voluntary reporting system.

Nor can the increase be explained totally by the rise in prescriptions, Moore says. The overall relative increase in adverse events was four times more than the growth of outpatient prescriptions, he says.

"About 25% of the change [in numbers of reports] is explained by more drug prescriptions to a growing, aging population."  As expected, the number of adverse drug effects was higher in older people than younger ones. While people 65 and older account for 12.6% of the total U.S. population, they accounted for 33.6% of the reported adverse drug effects, Moore says.

Children under age 18 accounted for 7.4% of the serious adverse effects, he says, although they make up 25.8% of the population.

Biotechnology drugs, a whole new kind of drugs and products created by genetic engineering, is another reason for the increase, Moore tells WebMD. An example is Remicade, prescribed for rheumatoid arthritis and other problems, which is on the list of drugs that commonly cause adverse effects, including death.

"Painkillers have always been a problem, especially the opioids, but it seems to be getting worse," Moore says. "They are being used more." Fentanyl patches, for instance, made the list of common offenders, and Moore say they are "hugely powerful and very addictive."

Other Experts Weigh In

Another expert on medication safety agrees that the new report is cause for concern. And the numbers reported in the recent study are probably "the tip of the iceberg," says David W. Bates, MD, director of the Center of Excellence for Patient Safety Research and Practice at Brigham and Women's Hospital in Boston and professor of medicine at Harvard Medical School in Boston.  Many more adverse drug events, he suspects, go unreported.

Consumers may avoid problems, he says, by taking advantage of pharmacist consults about drugs and knowing the potential side effects. "There is some evidence that if patients know about the possible adverse effects, they are less likely to have a problem," Bates says.

"If I were taking any of the drugs on that list, I would indeed learn a significant amount about their adverse effects," Moore tells WebMD. "Consumers need information. They really need to know more about the drugs they take."

Moore says the FDA also needs to have much more authority to govern drug safety.

SOURCES: Thomas J. Moore, senior scientist, drug safety and policy, Institute for Safe Medication Practices, Huntingdon Valley, Pa. Moore, T. Archives of Internal Medicine, Sept. 10, 2007; vol 167: pp 1752-1759. David W. Bates, MD, director, Center of Excellence for Patient Safety Research and Practice, Brigham and Women's Hospital; and professor of medicine, Harvard Medical School, Boston..

©2007, WebMD Inc. All rights reserved.


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