Inappropriate drug prescribing for the elderly is still common, with possible risks in about one in five prescriptions, a Dutch systematic review found.
In 19 published studies, the median rate of inappropriate prescriptions was 20%, with a range of 2.9% to 38.5%, according to Dedan Opondo, PhD, of the University of Amsterdam, and colleagues.
The highest rates were for propoxyphene (Darvon and others), doxazosin (Cardura), diphenhydramine (Benadryl and others), and amitriptyline (Elavil and others), all prescribed for older individuals at rates exceeding 3% to 4%, the researchers reported online in PLoS One.
"Despite intensified efforts to scrutinize and improve the quality of medication prescription among elderly persons in the primary care setting, inappropriate medication prescriptions are still common," wrote Opondo and colleagues.
In fact, more than one-third of at-risk older individuals experience drug-related adverse events, even in cases where less hazardous options are available, they noted.
To explore this ongoing problem, the researchers searched the literature for studies assessing the use in older patients of multiple types of drugs including analgesics, hypnotics, antihypertensives, and anticholinergics.
The 19 studies they identified were performed in 11 countries, primarily in Europe and the U.S., and most used the Beers criteria for inappropriate medication use.
Among the nonsteroidal anti-inflammatory drugs, they found that propoxyphene, which is classified as low risk, was the most common inappropriate medication, given at rates of 4.52%. The higher-risk agents pentazocine and meperidine (Demerol) were the least common, being prescribed for the elderly in rates of 0.03% and 0.1%, respectively.
For antiarrhythmics, digoxin was the most commonly used inappropriate medication, at 3.10%, while disopyramide (Norpace) was the least common, at 0.08%. Digoxin is considered low risk and disopyramide is considered high risk.
Within the anticholinergic class of drugs, the high-risk agent diphenhydramine was most often used, with rates of 3.3%, while the least common, at 0.04%, were the belladonna alkaloids, which also are high risk.
The most frequently prescribed inappropriate anti-clotting medications were high-risk ticlopidine (Ticlid), given at rates of 0.86%, and low-risk dipyridamole (Persantine), with rates of 0.65%.
Among antidepressants, amitriptyline was the most common and doxepin was the least used, with rates of 3.2% and 0.6%, respectively, with both agents being considered high risk.
Doxazosin, a low-risk agent, was the most common inappropriate antihypertensive prescribed, at 3.96%, while guanethidine, a high-risk drug, was the least prescribed, at 0.05%.
For muscle relaxants, cyclobenzaprine (Flexeril and others) topped the list, at 1.95%, while metaxalone (Skelaxin) was lowest, at 0.05%. Both are high risk.
And among sedative hypnotics, all of which are considered high risk, diazepam (Valium) was the most used, at a rate of 2.74%, and both alprazolam (Xanax) and oxazepam (Serax) had the lowest rates, with both at 0.05%.
Because the risks can vary widely in the elderly within drug classes, clinicians should attempt to avoid the riskiest agents and systems need to be in place to assist them, according to the authors of the review.
"There is therefore a need to move towards interventions that can improve the quality of medication prescriptions among the elderly in primary care such as by employing clinical decision support systems," they wrote.
These systems, when well designed, can alert the clinician at the time the prescription is written of potential side effects and interactions, they noted.
Primary source: PLoS One
Source reference: Opondo D, et al "Inappropriateness of medication prescriptions to elderly patients in the primary care setting: a systematic review" PLos One 2012; DOI: 10.1371/journal.pone.0043617.