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Some drugs can cause potentially harmful side effects, such as damage to vital organs. Doctors, however, may be able to lower the odds that a patient will be harmed by these side effects by having the patient get certain laboratory tests when he or she starts taking such "high risk" drugs. These tests look for early signs of trouble so patients can be switched to lower doses or different drugs, if needed.

Because older adults tend to have more health problems and take more drugs than younger adults, they run a higher risk of such drug side effects if they don't get proper monitoring while taking such medications.

New Research in the Journal of the American Geriatrics Society

To get a better sense of how often older patients who are taking drugs that can cause harmful side effects fail to get necessary laboratory monitoring, researchers studied the records of nearly 200,000 adults. These adults were all 65-years-old or older, in 10 U.S. health maintenance organizations (HMOs). All of the adults were taking heart mediations that are associated with potentially harmful side effects and that usually warrant laboratory monitoring. These drugs were: angiotensin-converting enzyme (ACE) inhibitors; angiotensin-receptor blockers (ARBs); digoxin; diuretics (or "water pills"); potassium supplements; "statin" drugs; and amiodarone.

The researchers classified instances in which patients did not get the kind of laboratory monitoring that is usually recommended as "monitoring errors." And they found a high rate of monitoring errors-anywhere from 23% to 58%-depending on the particular drug taken. The rate of monitoring errors among patients prescribed potassium supplements was 23%. Among those taking amiodarone, which is prescribed to correct life-threatening heart rhythm problems called ventricular arrhythmias, it was 58%.

Physicians may not have prescribed certain standard laboratory tests for a number of reasons, the researchers note. In some cases, for example, patients may have been prescribed "high risk" heart drugs for just a short period of time, and their doctors may have decided laboratory monitoring wasn't necessary because the drug would be used only briefly.

Interestingly, the researchers found that monitoring errors were lower among patients with more illnesses than among those with fewer illnesses. One possible explanation for this is that their health care providers were more aware of safety concerns among sicker patients.

The study did not determine whether laboratory monitoring errors led to health problems. This is something future studies should do. Ultimately, this information may help physicians better determine when to order laboratory monitoring. And this, the researchers note, could help improve patient safety, and lower both the risk of medical complications, and medical costs.

What Should I Do?

The best way to ensure you're getting appropriate drug treatment-which may include laboratory monitoring-is to discuss your treatment with your doctor.

You should:

• Talk to your health care provider about all the medications that you are taking at least once a year, to find out which are still necessary.
• Ask about possible side effects whenever you are prescribed a new drug, and learn about warning signs of potential side effects.
• Ask about follow-up and monitoring: Are there any monitoring tests you should be getting? When should you return for a follow-up visit to make sure the drug is working, and not causing potentially harmful side effects?
• Tell your doctor, immediately, if you think any of the medications you're taking are causing side effects.

For more information on taking medications safely, including information about drug side effects and monitoring, visit:

http://www.healthinaging.org/agingintheknow/chapters_ch_trial.asp?ch=6#reactions

The summary above is from the full report titled, "Baseline Laboratory Monitoring of Cardiovascular Medications in Elderly Health Maintenance Organization Enrollees." It is in the December 2005 issue of the Journal of the American Geriatrics Society (Volume 53, Issue 12). The report is authored by Steven R. Simon, MD, MPH, Susan E. Andrade, ScD, Jennifer L. Ellis, MSPH, Winnie W. Nelson, PharmD, MS, Jerry H. Gurwitz, MD, Jennifer Elston Lafata, PhD, Robert L. Davis, MD, MPH, Adrianne Feldstein, MD, and Marsha A. Raebel, PharmD.