The content and quality of information supplied with drug products are among the most specifically defined areas associated
with the products for sale. For patient or drug user, the information is presented in patient information leaflets (PILs)
placed in the package. The readability testing of PILs is an important stage in the process of making the texts contained
in the summary of product characteristics comprehensible to users, as this article discusses.
Despite its small size, drug packaging provides a great deal of information for the patient and user of the treatment - both
on the packaging itself and on the leaflet inside the package. The information on the outer package ensures that the correct
drug is supplied. The patient information leaflet (PIL) within the package contains information concerning the indications,
the dosage and any potential adverse effects. All these details should be based on the approved summary of product characteristics
(SPC) of the drug. The primary responsibility for the accuracy of the information and for its comprehensibility lies with
the marketing authorization holder and the manufacturer. The authorities assess the factual contents of the information at
the processing stage of the marketing authorization.
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Summary of product characteristics
The SPC is a drug description designed on the basis of research results and aimed at medical prescribers and other health
care professionals. The purpose is to give adequate and up-to-date information regarding the drug and, thereby, ensure successful
treatment. The SPC, approved in association with the marketing authorization approval process, is an essential part of the
marketing authorization and should form the basis of all the information given concerning the drug and its marketing. After
approval, the SPC may not be changed without the consent of the authorities.
Patient information leaflet
The marketing authorization holder draws up a legible and comprehensible PIL based on the SPC and intended for the drug user.
Naturally, the text of the SPC intended for drug prescribers is not the same, and is not appropriate, as that directed at
patients. The PIL follows the normative headings given by the authorities and an established order of presentation. The PIL
contains headings taken from questions frequently asked by patients and the replies are presented in clear language. Typical
questions are, for example:
- What does the drug contain?
- What is the effect of the drug?
As an aid in the design of the PIL, a legibility study can be used from which it is possible to assess the clarity of the
information given in the PIL, the sequence of the details offered and the actual presentation.
A good PIL has a clear, simple and short structure that is comprehensible to the user. The user is generally only interested
in the type of information that will give a clear answer to questions regarding what he/she should do and what results/side-effects
are to be expected. Clear instructions for use and dealing with possible emergencies are essential. The text of the PIL should
avoid unnecessary general information that may obscure any message essential for the use of the drug. Positive instructions
and active language targeted directly at the patient are preferred.
The presentation is of great importance from the point of view of readability and comprehensibility. The text should be of
sufficiently large type and easily readable. Different colours and text sizes may be used for distinguishing purposes. Clear
listings of adverse effects, for example, improve the ease of understanding of the message. The following is a list of some
general observations associated with readability:
- It is recommended that the headings be emphasized with different colours.
- Numbering of the main headings will help the reader to follow the text of the PIL; this is particularly important when the
PIL is double-sided or folded several times.
- The main headings should be placed on the left, not centred.
- The text size of the main headings should be a minimum of 13 point.
- The less important information (the marketing authorization holder and manufacturer, addresses) may be written using a smaller
- Types of text should be indicated rather than the texts themselves.
Test of readability of the PIL
The European Union (EU) drug legislation requires that the PILs should be clear and comprehensible. The current guidelines
also mention a readability test, which is to be conducted among the PIL users, and which will allow the comprehensibility
and clarity of the PILs to be studied. The Guideline on the Readability of the Label and Package Leaflet of Medicinal Product for Human Use (published in Rules governing medicinal products in the European Community; Notice to Applicants, Vol. 2C) was approved in
1998. The guideline recommends the use of a readability test developed in Australia to be used in the assessment of clarity
and comprehensibility of PILs. If other methods than the EU model are used in the design of the PIL, the testing of readability
is entirely the responsibility of the marketing authorization holder.
For several years, there has been particular attention paid to associating the readability test with the centralized procedure
of marketing authorization approval processes. The PILs of a number of drug products have been put through the readability
test in accordance with the EU guideline. These tests have permitted better understanding of the problems associated with
The readability is tested with a series of questions, some of which directly concern the factual content of the PIL. A typical
question could be, for example: Imagine that you are allergic to penicillin; could you, in that case, use this medicine? Some
of the questions are aimed at testing the general structure of the PIL (for example, the ease or difficulty of finding required
information) and could typically be: What are the disadvantages of the PIL, and how could the PIL be improved? The time allowed
for the test is naturally limited. The readability test can be done in two stages, which will provide an opportunity to find
out whether the improvements made on the PIL have had any effect on its readability.
There are complexities involved in the readability test. The test methods are not yet quite established and the testing of
the reliability of the various methods is inadequate. The question is, are we testing the readability of the PIL or the comprehensibility
of the list of questions?
In accordance with the EU guideline, the various languages are divided into three groups, and one language of each group is
required for the testing of readability:
- (A) French, Italian, Portuguese and Spanish
- (B) Dutch, English and German
- (C) Danish, Finnish, Greek and Swedish.
Some of the languages, particularly those in group C, are not related to each other, which makes it doubtful whether any conclusions
can be drawn from the results. A review of the analysed tests shows that there have seldom been any important differences
between the results from different countries, which is why the testing of various language versions should be expanded.
The content and quality of information supplied with the drug products are among the more specifically defined areas associated
with the products for sale. The size of drug packaging is rather small; inserting adequate labelling that would satisfy everybody
on the outer package is consequently impossible. Including all information essential for the choice of over-the-counter (OTC)
drugs in the PIL is, of course, difficult. In the selection of services they offer, pharmacies should focus on whether it
is possible for patients to familiarize themselves with the information leaflet.
Patient information leaflets are sources of information that complement the package labelling. The readability testing of
PILs is an important stage in the process of refining the texts contained in the SPCs to make them comprehensible to the users.
Readability testing of PILs is not legally required by the authorities, but such tests may improve PILs. The responsibility
of PILs lies distinctly with the marketing authorization holder, whereas the correctness of the factual contents is checked
by the authorities. From the patient's viewpoint, the implementation of readability testing could be a step towards improved
The European Council of Ministers has adopted the new EU pharmaceutical directive. As part of the proper use of medicinal
products, the rules on packaging have been updated to take into account the experience acquired. Based on the new directive:
"The package leaflet shall reflect the results of consultations with target patient groups to ensure that it is legible, clear
and easy to use." Additionally, more requirements are set for the applicants of the marketing authorization as it is stated
that concerning packages and PILs: "The results of assessments carried out in co-operation with target patient groups shall
also be provided to the competent authority."