Medication errors are a major cause of patient morbidity and mortality in
nearly all medical specialties. More than 7,000 deaths each year in the United
States are attributed to medication errors, according to a recent Institute of
Medicine report, and researchers have estimated that nearly 60 percent of all
adverse events are the result of medication errors. Nonetheless, few studies
have examined medication errors in psychiatry.
Medication errors can result either from a prescribing error or a
dispensing error or a combination of both. A new study by a group of British
pharmacists suggests that in psychiatry, prescribing errors are fairly
David Taylor, Pharm.D., the chief pharmacist at Maudsely hospital in
London, teamed with pharmacists at other U.K. National Health Service mental
health centers to evaluate all prescriptions written in a one-week (five
working days) period in June 2004. Their report appears in the July
Journal of Psychopharmacology. The study was funded by the United
Kingdom Psychiatric Pharmacy Group.
A total of 22,036 prescriptions were reviewed from eight outpatient acute
mental health centers and one inpatient psychiatric hospital to identify
errors in the writing of the prescription that could result in "an
unintentional significant reduction in the probability of treatment being
timely and effective, or an increase in the risk of harm when compared with
general accepted practice."
Prescribing errors were categorized by pharmacists at the nine sites as
grade 1, an error or omission of doubtful or negligible importance; grade 2,
an error or omission likely to result in minor adverse effects or worsening of
condition; grade 3, an error or omission likely to result in serious effects
or relapse; or grade 4, an error or omission likely to result in fatality. A
panel of five "expert psychopharmacologists" reviewed all grade 3
and grade 4 errors and assigned a consensus
Of the more than 22,000 prescriptions checked, 11,668 (52.9 percent) were
for psychotropic medications. Prescribing errors meeting the study definition
were detected in 523 (2.4 percent) prescriptions. More errors occurred with
prescriptions for antipsychotics (17 percent) than for any other category.
Hypnotics and anxiolytic medications were involved in the second highest
proportion of prescription errors (13.2 percent).
Taylor and his colleagues found that "prescription-writing
errors" were far more common (77.4 percent) than "decision-making
errors" (22.6 percent). Errors categorized as involving the writing of
the prescription most frequently involved writing an incomplete prescription
(27.5 percent of total prescribing errors), such as not specifying a start
date or failing to completely specify dosage, dosage route, or frequency of
administration. In 13 percent of prescriptions, the prescriber neglected to
sign the prescription. The problem with 1.5 percent of the prescriptions was
illegible handwriting that could not be accurately transcribed by a
pharmacist. Other prescription-writing errors involved writing milligrams when
the drug strength should have been written as micrograms or misspelling a drug
"Decision-making errors" most frequently involved the"
prescribing of a dose regimen that is not recommended for the
drug/formulation prescribed" (9.8 percent of all prescriptions). Other
errors were categorized as involving prescribing a drug for a longer period
than recommended or approved (2.7 percent) or prescribing two drugs for the
same indication (1.9 percent). Dosages below the recommended effective dose
range for a patient's condition were somewhat less common (1.7 percent), as
was the failure by the prescriber to consider a potentially significant drug
interaction (1.1 percent).
The majority of patients receiving a prescription containing an error were
inpatients (83.4 percent) and were between the ages of 18 and 64 (69.2
percent). In 280 of the 523 errors (53.5 percent of prescription errors), the
medication was administered to the patient before the error was
Fortunately, the majority of the errors identified in the study were grade
1 (47.8 percent) or grade 2 (45.9 percent). Only 17 errors (3.3 percent) were
classified as grade 3 or grade 4. Most of these 17 errors involved the
prescribing of high doses of single drugs or of multiple drugs that when taken
together could result in serious central nervous system depression,
potentially precipitating respiratory failure.
Overall, Taylor and his colleagues concluded, "pharmacy staff
detected on average one prescribing error for every 42 prescriptions
checked." Over three-fourths of the errors amounted to "slips of
the pen," that is, were a prescription writing error. Thankfully, they
noted, "most errors were of doubtful or minor importance, but "1
in 33 errors was deemed likely to result in serious effects or
"Prescription Error in Psychiatry: A Multi-Center Study"
is posted online at<http://jop.sagepub.com/cgi/content/abstract/20/4/553>.▪