20% of US adults get prescriptions for analgesics, yet little is known about the safety of these drugs. In recent years, a number of high profile lawsuits have caused an upheaval in the public’s trust of prescribed pain medication. If you haven’t been concerned about the safety of your pain medications, you should be.

According to Solomon, et. al, authors of „The Comparative Safety of Analgesics in Older Adults With Arthritis“, published in Archive of Internal Medicine this month, most randomized clinical trials – which includes studies the FDA requires of a drug maker before their product can be sold on the market – look at how well a pain med works, but NOT how safe it is. They say that most of the time, study subjects are healthy, unlike the people for whom the drug is meant. Add to this the fact that as a general rule, long term side effects are rarely evaluated in studies, and you have cause for doubt about pain med safety, in my opinion.

Two studies evaluating health risks associated with taking pain meds made the news recently. The news reports I read focused on the findings that giving opioids (narcotic pain medications) to people over the age of 80 increased their risk of complications, health problems and even death. Of course, conventional pain doctors who commented in the news reports tried to refute the results by saying the study had serious problems with confounding. Little information about exactly what skewed the results was given in the news reports.

Confounding happens when a researcher observes people to find out what causes or at least is associated with a particular effect. Investigators may hypothesize that one characteristic is responsible for a disease or condition.  But another characteristic, related to the one they are evaluating, emerges as a possible cause during the course of the study.  So the hypothesis just got more complicated.  In the two recent studies, confounders included any possible role that obesity, smoking, drinking and the use of over the counter pain meds (NSAIDs) may have played in the safety of those who took opioids or Cox-2 inhibitors.  In other words, the researchers were unable to factor these things in when they looked at safety events resulting in hospitalization and/or death in seniors taking opioid pain medication.

The study authors talked about this problem in their report, acknowledging the possibility that something other than the medication was at work here. They described the way in which they created comparable groups of pain med taking seniors. And as it turns out, these remaining factors (smoking, drinking, being overweight and taking NSAIDs) occupied only a small fraction of the overall possible causes of the health risks identified in the two studies.

The study compared opioid use to NSAID use, as well as to the use of Cox-2 inhibitors.

The studies found that:

  1. opioids are likely not as safe as previously thought and
  2. the different opioid medications each have different degrees of risk.

Hopefully these studies will trigger more safety studies, but the authors rather doubt that.

As with most studies, the authors end by saying more studies are necessary before we can definitely know the best course of action for patients.

Sources:

Solomon, D. MD, et. al. The Comparative Safety of Analgesics in Older Adults With Arthritis. Arch Intern Med. Vol 170 Dec 13/27 2010. Accessed: Dec 21 2010.

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