According to a recently released study every year, as many as 700,000 people end up in hospital emergency departments because they experience an adverse drug effect, and 117,000 of those have to be hospitalized.
It is common in this day and age for people to be using least one doctor prescribed medication, along with over-the-counter medications, or a dietary supplement.
It was estimated in 2004 that 82 percent of the U.S. population reported doing so with 30 percent using 5 or more such drugs.
The study says that while these medications may offer substantial benefits, there also may be risks.
Collecting information on outpatient adverse drug events (ADEs) is not an easy task but the researchers say the problem is large and can be expected to increase.
Daniel S. Budnitz, M.D., M.P.H., of the Centers for Disease Control and Prevention, Atlanta, and colleagues analyzed data from January 2004 through to December 2005, from 63 hospitals taking part in the National Electronic Injury Surveillance System-Cooperative Adverse Drug Event Surveillance project (NEISS-CADES).
They wanted to determine the frequency and characteristics of ADEs in the U.S. that have led to emergency department visits.
They found that over that period 21,298 adverse drug event cases were reported and they estimate that more than 700,000 patients would have been treated for ADEs in U.S. emergency departments annually in 2004 and 2005.
One out of every 6 of those required subsequent hospital admission, transfer to another health care facility, or emergency department observation admission.
People aged 65 years or older were more than twice as likely to be treated in emergency departments for such an event and were almost 7 times as likely to require hospitalization than younger individuals.
Emergency department visits for ADEs in this age group were apparently almost as common as those for motor vehicle occupant injuries.
Most patients who were hospitalized due to unintentional overdoses and two-thirds of these were due to toxicity from a relatively small set of drugs for which regular monitoring is commonly required to prevent acute toxicity.
The researchers say sixteen of the 18 drugs most commonly causing ADEs have been in clinical use for more than 20 years, and insulins or warfarin and digoxin, drugs that typically require ongoing monitoring to prevent overdose or toxicity, were implicated in 1 in every 7 estimated ADEs treated in emergency departments.
Some commonly used medications were also often responsible for adverse events with nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, causing about 3.3 percent of the adverse drug events, while antihistamines and cold medications were responsible for about 4 percent of the problems.
The research is published in the current issue of the Journal of the American Medical Association.