Any noxious, unintended effect of a drug when utilized for prophylaxis, diagnosis or treatment.
About one third of adverse drug events are associated with medication errors and are thus preventable.
ADEs are usually considered to have several components, including mistakes, drug interactions, and unpredictable side effects.
Severe adverse drug events contribute 20% of all hospitalizations in older adults, with an associated cost of $900 million in the US per year.
ADEs are estimated to result in over 750,000 injuries and deaths each year, with excess costs of as much as $5.6 million for a large hospital.
Incidence rates of ADEs vary from two to seven per 100 admissions in hospitals.
Adverse drug events associated with an estimated 4.5 million ambulatory care visits per year during 2005-07 (Sarkar IJ et al).
In 1994 estimated 106,000 hospital patients died from adverse drug reactions.
Accounts for 3-5% of hospital admissions, and 5-10% of in-hospital costs.
Aside from adverse drug events many patients experience inappropriateness of their medications, that is unwanted polypharmacy, suboptimal management, therapeutic ineffectiveness, safety issues such as drug to drug interactions, supratherapeutic doses and adherence.
Of the estimated 90,000 emergency department visits each year for adverse reactions related to psychiatric medications, sedatives and hypnotics makeup 34.5%, anti-depressants make up 28.5%, antipsychotics 24.2%, lithium salts 4.1% and stimulants 3.1% (Hampton LM et al).
Older adults have been nearly 7 times more likely risk of having an adverse drug event that requires hospitalization than younger persons.
Older adults have more adverse drug events due to age-related decline in renal and liver function, more comorbid illnesses, use of multiple medications.
Estimated 99,628 emergency hospitalizations for older adults for adverse drug events in the US and the major drugs involves warfarin, a oral anti-platelet drugs, and oral hypoglycemic agents.
Estimated cost annually of drug related problems in the ambulatory setting $76.6 billion dollars.
Drug related adverse reactions more common in older patients because they are frequently on multiple drugs and therefore at risk for drug interactions, and because age is associated with pharmacokinetic and pharmacodynamic changes (Aronson JK).
Estimated 40% of adults in 5 years or older take 5-9 medications, while additional 18% to 10 or more medications (Budnitz DS et al).
Factors that increase risk of adverse drug reactions include: age, number of drugs, alcohol use, comorbidity, renal insufficiency, hepatic insufficiency, heart failure, and anemia.
Estimated to be the fourth leading cause of death after heart disease, cancer and stroke.
Severe adverse drug reactions in hospitalized patients occurs in greater than 6% of patients.
The most common adverse drug events (ADE) are related to antiplatelet therapy, anticoagulants, diuretics, nonsteroidal anti-inflammatory agents-all of which make up more than 50% of preventable ADE related hospital admissions.
Additional classes of drugs associated with adverse drug events include insulin, oral hypoglycemic agents and anti neoplastic agents.
Hypoglycemic agents and insulin implicated in one fourth of emergency hospitalizations for adverse drug events among older U.S. adults.
Almost all adverse diabetes related drug events are for hypoglycemia.
Sulfonylureas lead to most ED visits for hypoglycemia.
The percentage of adverse drug events are dose related 75%-85% of the time.
Greater then 27% of adverse drug reactions are considered preventable.
Greater tendency for elderly patients to experience adverse drug events.
Women have a 1.5- to 1.7-fold greater incidence of adverse drug reactions than men.
The use of multiple drugs exponentially increases the risk of such reactions.