Drugs most frequently reported for adverse reactions

by Michael R. Cohen, R.Ph.

You may be surprised to learn that in 2011, the Food and Drug Administration received 179,855 reports of serious or fatal adverse drug reactions. This was an increase of 15,386 reports (9.4 percent) from the 2010 total. Reports reached the FDA through two mechanisms. Voluntary reports from health professionals and consumers and reports from manufacturers. There were 21, 002 voluntary reports and 158,853 from manufacturers. Manufacturers must report serious events within 15 days of becoming aware.

The 10 drugs with the largest numbers of reports sent directly to the FDA by healthcare practitioners and consumers in 2011 in order of frequency are Pradaxa, Coumadin, Levaquin, Carboplatin, Zestril, Cisplatin, Zocor, Cymbalta, Cipro and Bactrim. Keep in mind that this is not a scientific study of the frequency of adverse drug events in clinical practice. These are the medications that health professionals and consumers told the FDA were causing serious and fatal side effects during 2011. It is interesting to note that just two of these drugs were first introduced in the last decade (Pradaxa and Cymbalta), and only one in the previous year (Pradaxa), suggesting that major drug safety issues are not confined to recently approved drugs.

Pradaxa surpassed all other monitored drugs in several categories, including overall number of reports (3,781), deaths (542), hemorrhage (2,367), acute renal failure (291), and stroke (644). It was also suspect in 15 cases of liver failure. Coumadin has been prominent in the rankings for many years. It accounted for 1,106 reported ADEs overall, including 731 reports of hemorrhage and 72 deaths.

In 2011, Remicade, a drug used for rheumatoid arthritis, psoriasis, ulcerative colitis and other conditions, accounted for 159 reported cases of severe liver injury, and acetaminophen (Tylenol), 139 cases. The liver has the capacity to recover from moderate injury, a problem reported with many drugs, but a few drugs can overwhelm the liver, leading to severe liver injury or liver failure. Two drugs accounted for the most reported cases of severe skin reactions – the epilepsy drug Lamictal and the anti-smoking drug Chantix. The most reports involving thoughts of injury to self or to others, with 197 reported cases, was Seroquel, a drug developed for psychosis but now used for a wide variety of conditions including depression and off label as a sleep aid. Ranked second was Chantix (187 cases).

Among the nine drugs resulting in severe side effects most carry some form of FDA-approved warnings - often prominent ones. On one hand, this shows that FDA and manufacturer safety surveillance programs have identified these significant safety risks. On the other, it illustrates that placing warnings in product information only begins the process of managing the risks.

The suspect drugs identified in this annual report include some of the most widely used and valuable prescription drugs currently available. But, the substantial health benefits achieved only increase the need to do a better job managing their risks.

The data above come from QuarterWatch™ an Institute for Safe Medication Practices surveillance program that monitors all serious and fatal adverse drug events (ADEs) reported to the Food and Drug Administration through MedWatch, its adverse event reporting system.

The goal is to identify signals that may represent important new drug safety issues. The term "signal" as we use it means evidence substantial enough to warrant mention but which usually requires further investigation to determine how frequent an ADE happens and to establish a causal relationship to a drug. Our latest edition examines annual reporting totals, trends, and ADE signals from 2011.

The growth in reported events is primarily due to reports from manufacturers. The intense marketing of newer brand name drugs, like drug specific Web sites and communication systems, results in frequent contact with healthcare providers and patients, which allows the drug manufacturers to learn about more adverse events. However, reports from health professionals and consumers, who are concerned enough to report an observed ADE to the FDA, remain one of the best resources available to assess drug safety risks.

There is a general consensus in the drug world that only about 1 percent of serious events ever get reported to the FDA. If that is true, and taking the 179,855 events that were actually reported, a conservative estimate is that there may have actually been as many as 18 million serious reactions last year. If 10 percent were reported then a lower estimate of 1.8 million would be the case. Obviously, that's still an enormous number.

The full QuarterWatch™ report can be viewed at: www.ismp.org/QuarterWatch.

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