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Emma Graham-Clarke is a locum consultant pharmacist,
and Nigel Langford is a locum consultant physician, from Birmingham
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Concern exists over look-alike or sound-alike drug names such as Losec
and Lasix and the possibility that error may arise.1 It has been shown
how error can exist when two products can also look similar, such as
sodium chloride and lidocaine ampoules.2 A brief search on Medline, looking
at medication errors and drug packaging, produced nearly 400 hits. Similar
searches using PJ Online showed over 1,000. Although not all the citations
are directly relevant, it is an indication of the thought and concern
that is generated by the medicines we supply in whatever form. Undoubtedly,
much confusion has been caused for patients by similar packaging and
names, let alone for the health care professionals concerned with their
care.
Preventing such errors is not simple. For example, with labelling, two
opposing camps appear. One supports the development of similar packaging
on the basis that there is no substitute for reading the label. As a
corollary it is often pointed out that there is a limited number of colour
combinations, especially when colour blindness problems are taken into
consideration. The other camp looks for some degree of differentiation
using colour or pack design to minimise errors.3 Although these are all
important areas to be addressed, a more fundamental problem involving
the identity of tablets themselves has been discovered.
Toothill recently reported in The Pharmaceutical Journal that tablets
of IVAX gliclazide and Goldshield captopril4 are identically marked.
In a similar vein, we recently reported Goldshield captopril and Milpharm
gliclazide tablets being identical and the subsequent confusion that
arose.5 As far as the manufacturers were concerned they had done nothing
wrong; the markings were their licensed marks for those tablets. When
we contacted the Medicines and Healthcare products Regulatory Agency,
it helpfully pointed out that the tablet markings were there for identification
purposes! In order to identify our tablets we had to resort to our toxicology
laboratory. The problem is compounded when one company manufactures tablets
that are then packaged by other companies into their respective liveries.
This situation will worsen with the expansion of the generic houses.
In hindsight it would have been easier if the tablets had had no markings.
Markings are there not only to help the manufacturers identify the tablets,
but also to assist health care professionals in the identification of
loose tablets. We are so used to tablets being issued in strip packaging
that much thought has been expended in improving the design and layout
of such packagings. Indeed, from the packaging, these two tablets would
not have been confused. However, in the concern to improve this area
we have lost sight of the single unit — the tablet or capsule — and
the ability to identify them quickly.
As the population ages the number of medical ailments people have increases,
leading to an ever-increasing number of medicines being prescribed. Facilitating
patient compliance with treatments becomes increasingly difficult. To
help with such problems various compliance aids
have been introduced. Unfortunately, most of these involve removal of
the solid dosage form from its packaging. Furthermore patients have always
had a tendency to keep their medicines in unconventional and usually
unlabeled containers (coffee jars and cigarette packets among them).
Pharmacists have had to become increasingly skilled at trying to identify
them. As a result of this need and the expanding number of different
tablets and capsules available various tablet identification methods,
such as TicTac, have been introduced. More recently various internet
sites (eg, drugs.com) have also been developed to assist patients and
other concerned adults in the troublesome field of tablet identification.
However, all these methods are only as good as the information that is
supplied to them. At the moment there is no central registry office that
specifically compiles tablet markings. New tablets are added on an ad
hoc basis to the commercial databases,which depend on users to alert
them to the presence of new medicines. The degree of serendipity attached
to this method means that the database organisers always have to act
reactively, rather than, ideally, in a proactive manner. Having discovered
the presence of a tablet not on the database they have moved swiftly
to add it, but it is unrealistic for this to be a long-term viable method.
The commercial identification companies suggest that drug manufacturers
should check that potential tablet markings are unique by using their
databases. Unfortunately there appears to be no legal requirement for
this to be performed. Furthermore at present there is no requirement
that tablet markings have to be unique to the tablet concerned.
We strongly believe that part of the licensing procedure should include
checking of the uniqueness of the preparation. This should include not
only the name of the drug and packaging but also the tablet’s shape,
colour and markings. Additionally we wish for solid dosage forms to have
their markings recorded centrally, so that as products receive their
licences, a current and updated registry would be assembled.
However. perhaps a more far-sighted approach, as advocated by other authors,
would be the simple procedure of assigning a code to each individual
drug. Such a code could be generated at the same time as the approved
name. Although there are some practical difficulties, most solid dosage
forms could cope with a four-digit code being added to one side. It has
been calculated that using such a code consisting of letters and numbers
over 1,185,921 different identifiers could be created.6 Had such a method
existed, our problem of a woman presenting with her unlabelled dose administration
aid would have been resolved with minimal fuss and it would have been
a simple process to check if medication errors had occurred.
Reference
1. Hoffman J, Proulx S. Medication errors caused by confusion of drug
names. Drug Safety 2003;26:445–52.
2. Malhotra A, Matson M, Chan O. ... and packaging of
lignocaine must be changed. BMJ 2001;322:549.
3. Ferner R. Misleading drug packaging. BMJ
1995;311:514.
4. Toothill C. Two almost identical tablets (letter). Pharmaceutical
Journal 2004;273:149.
5. Graham-Clarke E, Langford N. Lancet 2004. In press.
6. Ferner R. Reducing medication errors. JAMA 2001;286:2091. |
The
Pharmaceutical Journal