Добавил:
Sekretar
kiopkiopkiop18@yandex.ru
t.me/Prokururor I Вовсе не секретарь, но почту проверяю
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5351_Библиотеки_им_академика_М_И_Перельмана.pdf
The prescribing process and evidence-based medicine CHAPTER 17
and any laboratory tests are entered on to the computer and this software compares these to information held on a database to suggest a diagnosis or
further investigations that might be required. The
NHS funds a service that helps ‘health care professionals confidently make evidence-based decisions
about the health care of their patients and provides
them with the know-how to safely put these decisions
into action’ (Clinical Knowledge Summaries 2008).
This service is called the Clinical Knowledge Summaries (CKS) service and is available through the National Library for Health on the NHS website. The
CKS is replacing PRODIGY which was the original
NHS decision support software. CKS also provides a
clinical summary of recommendations for managing
the patient’s condition and information to enable the
writing of a prescription, as well as providing access
to patient information leaflets developed by NHS
Direct.
Formularies
Drug formularies are lists of medicines that prescribers use (see Ch. 18). These range from personal
formularies from an individual prescriber to formularies used by one or more gen eral practices or o ne
or more trusts. It has been claimed that formularies
can improve prescribing by improving prescriber
familiarity with medicines as they only need knowledge of a limited range o f medicines. Formularies
that span diff erent organizations have the potential
to improve consistency of prescribing across the
primary–secondary care interface.
The process of producing a formulary can be very
time-consuming but it can be educational for those
contributing to the process. It provides organizations
with the opportunity to compare different medicines within a class on the grounds of effectivenes s,
safety, patient acceptability and cost and to consider
which medicines they wish to see prescribed by
prescribers in their organization. Deciding whom
to invite on to a formulary group to produce a new
formulary is an important stage in the process. In
small organizations, such as a general practice, it is
likely that all prescribers would be involved in the
selection of formulary drugs, but care should
be taken to include the views of those affected by
theformularysuchasthepracticenurse,health
visitors, district nurses and community pharmaci sts.
In larger organizations it would not be feasible to
includeeverybodyintheformularygroup.Where
possible each section or department should send a
representative who should be able to voice their
views and provide feedback.
The methods used to inform prescribers regarding
the formulary is another important step in the process, especially in large organizations as prescribers
could be unaware of its existence. The cost of printing
and distributing paper copies of the formulary will
depend upon the quantity involved and type of binding that is used. These can range from a printed book
to a ring binder with photocopied sheets. The formulary group should consider how often the formulary
will be updated and how user friendly the format is
to its prescribers, i.e. is it small enough to take on
ward rounds or to visit patients in their home. With
computer generated prescribing, the formulary medicines can often be highlighted or listed before nonformulary medicines.
In general, formulary groups should not expect
100% compliance with a formulary because there
are always likely to be exceptional patients who do
not respond to or have an ADR to certain drugs. The
formulary group should therefore decide what level of
compliance with the formulary they wish to see and
also how they can monitor the actual compliance with
the formulary. In some areas they will have no power
to insist that formulary medicines are prescribed
and they will have to persuade prescribers to consider
formulary drugs first. If compliance with the formulary is particularly low then the formulary group
should reflect on the suitability of the formulary
(are the right drugs in the formulary?) and method
of disseminating the formulary (are prescribers aware
of the formulary and is it in a format they can use
easily in their work?).
Competency framework
The National Prescribing Centre (NPC) is a n NHS
organiz ation whose aim is ‘to promote and support
high quality, cost effective prescribing and medicines management across the NHS, to help improve
patient care and service delivery’.TheNPChas
produced a competency framework which brings
together the knowledge, skills, motives and personal
traits that are considered to be required by a prescriber working effectively (NPC 2006). This
framework should be used as a checklist by prescribers preparing to prescribe for the first time and also
by prescribers reviewing their own practice as part
of their CPD.
169
SECTION THREE Pharmacy prescribing and selection of medicines
*
KEY POINTS
Evidence-based medicine closes the gap between
research and clinical decision making
*
Prescribing involves reaching a balance between
risk and benefit. Cost and patient choice are both
additional factors
*
The prescribing process can be viewed as having
five stages: having prerequisites, gathering
information, analysis, records and monitoring,
audit and evaluation
*
Pharmacists, with appropriate training, can
act as supplementary or independent
prescribers
*
Clear and complete records of all prescribing and
instructions must be kept in the patient’s medical
record
*
There are four stages to evidence-based medicine:
identifying the question, searching the literature,
making a critical appraisal, applying the evidence
to practice
*
The quality of evidence can vary and must be
appraised
*
Useful information sources include: Medline,
Embase, PubMed, Cochrane Library, NICE
publications, clinical evidence, computer based
clinical knowledge summaries, together with
formularies
*
The National Prescribing Centre has produced a
competency framework
170
Chapter Eighteen
Formularies
Janet Krska
18
STUDY POINTS
*
Different types of formularies
*
The benefits of using a formulary
*
Developing a formulary
*
Formulary management systems
Different types of formularies
Formularies were originally compilations of medicinal
preparations, with the formulae for compounding
them. The modern definition of a formulary is a list
of drugs which are recommended or approved for use
by a group of practitioners. It is compiled by members
of the group and is regularly revised. Drugs are usually
selected for inclusion on the basis of efficacy, safety,
patient acceptability and cost. Drugs listed in a formulary should be available for use. Information on
dosage, indications, side-effects, contraindications,
formulations and costs may also be included. An introduction, giving information on how the drugs were
selected, by whom and how to use the formulary, is
usually provided.
The most common formulary in use in the UK is
the British National Formulary (BNF), which compiles details of all the drugs available for prescribing in
the UK. It is produced by the Joint Formulary Committee, whose members include doctors and pharmacists as well as representatives from the Department
of Health. It is revised every 6 months and is issued to
all prescribers and registered pharmacies in both hospitals and the community. Formularies for dentists,
the Dental Practitioners’ Formulary, and for nurse
prescribers, the Nurse Prescribers’ Formulary, are also
included in the BNF. More recently a BNF for children was launched, in recognition of the need for
different, more detailed information about prescribing in children.
Local formularies, or lists of recommended drugs,
have been widely used in hospitals and increasingly in
primary care throughout the UK for many years.
Some are designed for small groups, such as one general medical practice, some are for all prescribers
within a hospital; others may be intended for all prescribers within a large geographical area. The latter are
often known as joint formularies, since they are compiled and intended for use by prescribers in both
primary and secondary care. A recent survey found
that 64% of primary care organizations have some sort
of formulary and 47% are joint initiatives with secondary care. The increasing availability of a funded minor
ailments service in community pharmacy, providing
selected medicines free of charge to certain patients,
has necessitated the development of formularies from
which local pharmacists can supply the recommended
products. Local formularies are usually developed and
maintained by an Area Drug and Therapeutics Committee (ADTC). These committees involve pharmacists, hospital doctors, general practitioners and nurses
who practise within a locality, and often also include
management, public health and financial expertise.
Worldwide, formularies are a concept which is promoted by the World Health Organization (WHO).
The essential medicines list (see Ch. 7) which is
recommended as necessary for basic health care in
developing countries is similar to a formulary. Any
country can modify this list to meet its own particular
needs and arrive at a ‘national formulary’. The basis of
any list is that the drugs it contains are of proven
SECTION THREE Pharmacy prescribing and selection of medicines
Table 18.1 Examples of formularies
Purpose Example formulary
General use British National Formulary
Hospital formulary University College London Hospitals NHS Trust Formulary
General practice Cambridgeshire Primary Care Trust Formulary
Joint formulary Tayside Area Prescribing Guide
Lothian Joint Formulary
Specialist formulary Palliative Care Formulary
Developing countries WHO Essential Drug List
therapeutic efficacy, acceptable safety and satisfy the
health needs of the populations they serve. Some
examples of formularies are given in Table 18.1.
A formulary may be thought of as a prescribing
policy, because it lists which drugs are recommended. Prescribing policies should, however, be
much mo re detailed than a formulary, giving details
of drugs which should be selected for use in specific m edical conditions. Examples of prescribing
policies in common use are antibiotic policies, head
lice eradication policies and malarial prophylaxis
policies.
Clinical guidelines contain more detailed information than a formulary about how a service should be
delivered or patients treated and do not always specify
the drugs to be used. Many are developed nationally,
such as by the National Centre for Health and Clinical
Excellence (NICE), Scottish Intercollegiate Guidelines Network (SIGN), British Thoracic Society,
British Society for Haematology and so on. Local
guidelines may be developed by ADTCs and are more
likely to include recommendations which specify
drugs included in the local formulary.
Benefits of formularies
Drug costs are a major component of the total cost of
the NHS and are constantly rising. As the resources
of the NHS are finite, it becomes increasingly necessary to contain the escalation in drug costs. Much
evidence shows that drugs are not always prescribed
appropriately. Therefore improving prescribing could
reduce expenditure on drugs. Local formularies
which recommend specific drugs and exclude others
are one means of achieving this. Prescribing policies
assist prescribers in using the drugs in a formulary and
specific treatment protocols make them even more
useful. Clinical guidelines help to ensure that the
treatment of patients is based on evidence of best
practice. Used together, formularies, clinical guidelines and treatment protocols can ensure that standards of prescribing are both uniform and high quality.
All these are tools used to promote rational and costeffective prescribing.
Rational prescribing
Prescribing which is based on the four important factors of efficacy, safety, patient acceptability and cost
should be rational. While many drugs may be available
to treat any particular condition, the process of selecting the most appropriate one for any individual patient
should take account of all these factors, plus other
patient factors, such as concurrent diseases, drugs,
previous exposure and outcomes. The four factors
can also be applied to selection of drugs to treat populations of patients and it is for this situation that formularies are developed. Providing drug selection is
based on good quality evidence of efficacy and toxicity, formularies then assist in making decisions regarding individual patients.
Cost-effective prescribing
Formularies often provide information on the cost
of products to help users to become cost conscious.
172
Formularies CHAPTER 18
Local formularies usually include only a small proportion of the drugs listed in the BNF, often between 200
and 500. If prescribers only use the range of drugs
included in a local formulary, the range stocked by
pharmacies can decrease, which reduces unnecessary
outlay. Using a restricted range of drugs may allow
pharmacists to buy these in bulk, further reducing
costs. Formularies also encourage generic prescribing
which may reduce costs even further. If fewer products are stocked, monitoring of expiry dates
becomes easier and cash flow may improve. Any money saved on hospital or on GPs’ budgets by using a
formulary may be used to benefit patients in other
ways. For example, reducing the prescribing of drugs
which have little evidence of therapeutic benefit,
such as peripheral vasodilators, could enable more
to be spent on lipid-lowering drugs. Formularies
may also recommend using more cost-effective alternatives to some expensive modified-release formulations. In addition, as safety is also a key factor in drug
selection, formularies may contribute to reducing the
incidence of adverse drug reactions, which often carry
a high cost.
Educational value
Compilation of a formulary involves researching the
literature to gather evidence of efficacy and toxicity. For those involved, this is a highly demanding
task, but one which is of considerable educational
benefit. There are also benefits for users of formularies. Prescribers who use a restricted range of
drugs should know more about those drugs and
their formulations through frequent use. Ultimately this should result in benefits for the patient, as
prescribers’ increased knowledge should r educe the
risk of inappropriate prescribing, which could contribute to adverse effects, interactions or lack of
efficacy.
Continuous care
A joint local formulary which covers both primary and
secondary care encourages the same range of drugs to
be prescribed, which makes continuing drug treatment across the interface easier. As patient packs
are increasingly dispensed, patients are more likely
to use their own drugs during a hospital stay. A joint
formulary helps this, as there is less chance of drug
therapy having to change to comply with a different
formulary on admission to hospital.
Formulary development
Formularies take a very long time to produce: several
years is not uncommon. Obtaining everyone’s opinions and discussing the drugs to be included are the
main reasons, for this prolonged time. A formulary
then needs to be updated regularly if it is going to
be useful, which is a further time commitment. There
are two basic ways of producing a new formulary –
either start from scratch or modify an existing one.
Adapting another formulary to suit local needs is
much less time-consuming than starting from scratch.
Although much can be learned from looking at someone else’s formulary, simply deciding to adopt it without any changes is not a good idea. Producing a
formulary is an educational process, during which all
concerned learn from each other’s experience and
update their clinical pharmacology and therapeutics
along the way. Producing a formulary also brings a
sense of ownership, which encourages commitment
to it and increases the chance of it being used. Local
needs should also be addressed by a local formulary, so
copying someone else’s may not be satisfactory.
A local ADTC is most likely to oversee the task of
developing a formulary. Although the committee will
include different healthcare professionals, pharmacists usually play a key role. Small subgroups of local
experts may do most of the development work, but
the opinions of potential users should also be sought.
This is a very important point in formulary development. The people expected to use a formulary must
have the opportunity to give their views on its content. If their opinions are not asked, they may feel that
it does not apply to them and will be less likely to use
it. Smaller formularies, such as for one general medical practice or ward, should be developed by all the
prescribers working in that practice or ward together
with a pharmacist. Such formularies may draw on the
work of ADTCs and select even fewer drugs from the
area formulary, but may add others. It is important
that formularies reflect the needs of the population
being treated. So obviously a formulary for a surgical
ward will differ from that for a general practice, but
both may be derived from the area formulary.
Content
The formulary should start with an introduction, giving the names of those who have compiled it, stating
who is expected to use it and explaining its format
(Fig. 18.1). It is important to state whether all the
173
SECTION THREE Pharmacy prescribing and selection of medicines
174
Formulary introduction and formulary recommendations for respiratory drugs, illustrating presentation as a Pocket Guide (reproduced with permission from Tayside
*
Figure 18.1
Area Prescribing Guide Pocket Guide 2007, copyright: NHS Tayside Drug and Therapeutics Committee).
Formularies CHAPTER 18
drugs included are recommended for all users, and if
not, how different recommendations can be distinguished. The BNF, for example, lists drugs the Joint
Formulary Committee considers less suitable for prescribing in small type. The examples in Figures 18.1
and 18.2 illustrate how the recommended first choice
drugs are highlighted. Local formularies may choose
to place restrictions on some drugs, for use by specialists only, for certain indications only or in certain
locations only. These drugs should also be easily distinguishable from the others in the formulary; in
Figure 18.1 these are in italic. A list of contents and
an index should be included to make the formulary
easy to use.
Most UK formularies follow the BNF to classify
medicines. Reference to the relevant BNF section is
helpful if a local formulary is designed to be used in
conjunction with it. Users can be directed to the
monographs there for information on dosage, indications, side-effects, contraindications and precautions.
Some formularies include all this information, but
only for the recommended drugs. Other important
information which may be given is local drug costs
and the reasons for selecting the drugs included.
Drug costs are one of the factors taken into account
when compiling a formulary(see below). Theprice of a
drug can be expressed in several different ways. The
prices given in the BNF are the prices of different pack
sizesor for20 doses ofgenericsat drug tariff prices. The
cost of a period of treatment may be more useful if
comparisons are being encouraged. A suitable period
may be 1 day, 1 month (28 days) or a standard course of
treatment (e.g. 5 days for antibiotics). Since the price
of the drug usually varies with the pack size, this may
not be as easy to calculate as it first appears. A further
complicating factor is the differing prices in hospital
and community. If a formulary is designed to be used
in hospital only, the hospital price may seem most relevant. However, the price of the drug may be different
in general practice and patients may takethe drug while
living in the community for much longer than they take
it in hospital. Therefore the price in the community is
also of relevance, especially in joint formularies.
When large numbers of prescribers are to use a
formulary, it is possible that not all of them will have
been consulted about its content. If that is the case,
providing explanations of how drugs have come to be
included in a formulary is of particular importance.
Many formularies state the general basis of drug selection as being efficacy, safety, patient acceptability
and cost. Sometimes additional information is given
about specific drugs, which can assist furthering drug
selection. The BNF gives this type of information in
introductory paragraphs to each section. An example
is the statement that ‘other thiazide diuretics do not
offer any significant advantage over bendroflumethiazide and chlortalidone’. It may be desirable to reference the formulary to give readers the opportunity to
see the evidence on which statements such as these
are based. It may also be useful to explain local
preferences, particularly in the case of antibiotic
selection, which should take local microbiological
sensitivities into account.
Some or all of the formulary may be presented as
prescribing policies. While this is most likely for antibiotics, policies may be included for any group of
drugs. If this approach is taken, details of which drugs
are to be used in specific medical conditions should be
given. It may be necessary to include alternatives and
the particular occasions when they should be used. In
a prescribing policy, details of the recommended dosage, route and method of administration and duration
of therapy should also be included.
A local formulary may have sections relating to
prescribing in certain types of patients, such as the
elderly, children, those with renal or hepatic impairment, or in pregnancy and breastfeeding. As there
is little point in reproducing the BNF, these too should
reflect local recommendations.
Presentation of a formulary
The appearance of a formulary is an indicator of the
importance attached to it by those who have produced
it. If it is presented on a few tattered sheets of paper,
those who are expected to use it are unlikely to have a
great deal of respect for its content. This may lead to
poor adherence to itsrecommendations.It is therefore
worth creating a document which is attractive and
looks professionally produced. It is also important to
consider whether a paper or electronic format is desirable or whether both should be available.
Paper formats can be portable, making for ease of
use in any clinical setting, from the hospital bedside to
the patient’s home. However, they are expensive to
produce and still require regular updating. The size of
the document is an important consideration. Ideally, it
should be no bigger than pocket-sized, perhaps compatible in size with the BNF, to make it easy to use the
two together. A simple list of formulary drugs is a
useful option, such as that illustrated in Figure 18.1,
produced by NHS Tayside Drug and Therapeutics
Committee. This can be supplemented by a larger
175
SECTION THREE Pharmacy prescribing and selection of medicines
176
Formulary recommendations for bronchodilators, illustrating presentation as a detailed prescribing guide (reproduced with permission from http://www.
*
Figure 18.2
nhstaysideadtc.scot.nhs.uk/TAPG%20html/Section%203/3-1.htm).
Formularies CHAPTER 18
document in either paper or electronic form. If the
formulary is only available as a large paper document
which cannot be carried around, it is much less likely
to be available when needed, which may mean its
recommendations are ignored. Colour and a durable
cover to withstand regular use can both add further to
the appearance of a paper formulary, but also increase
its cost.
Electronic formats are increasingly popular, but
not all professionals use a computer when prescribing, so it may still be necessary to produce a paper
version, ev en if this is only the list of drugs. A CD
version is one option, but like a paper document,
requires re-distribution whenever it is updated.
Local organizations, such a s hospital and primary
care trusts, have an intranet, on which the formulary can be published. Linking the local formulary
to electronic prescribing systems is perhaps the
ideal option. Some prescrib ing systems incorporate
decision support tools, which can include the formulary. Electronic v ersions may also make it easier
to evaluate the formulary by examining prescribing
adherence.
Ensuring that the formulary is up to date is extremely important and its presentation must allow
for this. Loose-leaf binding will enable easy updating,
but relies on everyone modifying their own copy. It is
much easier to update an electronic version which is
distributed via the Internet or intranet.
Whatever format is used, the formulary should
be easy to use, to encourage prescribers to refer to
it when necessary. This will be helped by a contents
list, which for a paper version means the pages have
to be numbered. Arranging the drugs in the same
order as the BNF will a lso help to make the formulary easier to use, as prescribers should be familiar
with this order. Using different typefaces and print
size can make a formulary easier to use. Highlighting the drug names can be useful, as often the name
of the recommended drug may be all that someone
is seeking (see Fig. 18.1).
Itmayalsobeappropriatetoprovideaccess
to the formulary for local patients. Increasingly,
patients have access to clinical guidelines and are
informed about what treatments are recommended
for their medical problems. Providing a formulary
has been developed using transparent methods and
drugs selected on the basis of efficacy, safety, patient acceptability and cost, there is no reason to
prevent patients from knowing of its existence. Access can be via the Internet, so need not a dd to
publication costs.
Selection of products for
inclusion
It is important to decide at the outset the range of
indications which the formulary should cover.
Some hospital formularies do not attempt to include drugs to treat all possible conditions. Some
deliberately exclude certain drugs, such as those
used in cancer chemotherapy and anaesthetics.
These areas are extremely specialized, so drugs in
these groups are never likely to be used by most
prescribers. A formulary for use in general practice
should aim to include enough drugs to treat between 80% and 90% of all common conditions
which present to a GP. It is also useful to include
emergency drugs, such as those which should be
carried by GPs in their emergency bags. Clearly if
a formulary includes all the available drugs, as does
the BNF, it will not only be bulky, but also will not
have many of the advantages that a local formulary
can provide. It should be possible to cover most
needs, either in hospital or general practice, with
about 300–500 drugs. In selecting drugs for inclusion in a formulary, it is important to remember
that recommendations are being made to treat the
majority of the population. However, individual
patients’ needs and preferences should, where possible, be taken into account. This means that there
may be individuals for whom the recommended
formulary drug is not suitable, but the formulary
should attempt to make provision for most commonly encountered situations. This usually means
that, out of the ran ge available, two dru gs from a
pharmacological class may be included rather than
one.
While the four important factors are efficacy, safety,
patient acceptability and cost, other factors are also
usually considered (Box 18.1). Formulary drugs must
be effective for whatever indications they are to be
used, with minimal toxicity. Evidence of efficacy
should be basedon well-conducted clinical trials rather
than anecdotal reports. Generally, prescribers’ personal preferences are not a sound basis for selection of a
particulardrug or product. This is especially true when
the formulary is to be usedby many prescribers, as each
may have their own preference. Occasionally there
may be a range of similar drugs from which to select,
but not all are licensed for all the indications the formulary is to cover. An example is beta-adrenoceptor
antagonists, some of which have a range of licensed
indications (Ta b le 1 8 . 2 ). In this situation, selection of
177
SECTION THREE Pharmacy prescribing and selection of medicines
Box 18.1
Factors influencing selection of drugs for
inclusion in a formulary
*
Efficacy for the indications to be included in the
formulary
*
Side-effect profiles and contraindications of
individual drugs
*
Interaction profile of individual drugs
*
Pharmacokinetic profiles of individual drugs
*
Acceptability to patients – taste, appearance, ease
of administration
*
Formulations available
*
General availability, including generic availability
*
Cost
*
Usage patterns
the drug which covers most indications may be appropriate. Alternatively, separate drugs could be selected
for different indications. This option resultsin difficulties when auditing adherence, as it is impossible to tell
from looking at prescribing data only whether the drug
is prescribed in line with the formulary recommendations.
If two drugs are equally efficacious, as is often the
case within a group of pharmacologically similar
drugs, the least toxic one is preferable. Any differences between the drugs in terms of their pharmacokinetics, contraindications, adverse effects and
potential for interaction then become important.
Pharmacokinetic profiles of drugs are important
in selecting drugs with an optimum half-life for
their indications. It m ay also be possible to select
drugs which are minimally affected by either liver
or renal impairment. Among the benzodiazepine
group, for example, those with short half-lives
and which have no active metabolites are usually
preferredashypnotics,astheyhavenohangover
effect. Differences in drug handling in children and
the elderly may require different drugs to be
recommended for use with these patients. Selection of drugs for use in pregnancy and breastfeeding
will be influenced by their passage into the placenta
and secretion into breast milk.
The range of contraindications, precautions and
adverse effects may differ for drugs within a therapeutic class. While class effects are common, sometimes there are differences between individual drugs;
again beta-adrenoceptor antagonists are a good example of this. Differences are most often found in the
frequency and severity of adverse effects between
drugs in a class. Where possible, formulary drugs
should have the lowest frequency of, and least severe,
adverse effects.
Table 18.2 Example using beta-adrenoceptor antagonists of how factors can be used to select drugs for a formulary
Factor Examples of information to be taken into account Examples of possible selection
Licensed indications For hypertension there are many to select from Atenolol, propranolol, metoprolol, etc.
OR For arrhythmias, few are licensed Sotalol, esmolol
Evidence of efficacy For secondary prevention of myocardial infarction Atenolol injection, metoprolol, propranolol
For heart failure Bisoprolol, carvedilol
Toxicity Water solubility results in less nightmares Atenolol, sotalol
Intrinsic sympathomimetic activity causes less
cold extremities
Contraindications Cardioselectivity is preferable in asthma and diabetes Atenolol, bisoprolol, metoprolol
Pharmacokinetic profile Long-acting drugs/products require fewer doses Atenolol, modified-release propranolol
Generic availability Usually reduces cost Atenolol, propranolol, metoprolol, bisoprolol
Acceptability to patients Once-daily doses, combination products may be useful Atenolol, co-tenidone
Cost Cheapest preferable if all other factors equal Atenolol, propranolol, metoprolol
Oxprenolol, pindolol
178