Chapter 17 The prescribing process and evidence-based medicine
The prescribing of medicines is the most common medical intervention in patient care and drug costs are a major component of NHS expenditure. Ensuring optimum benefits for patients and value for money for taxpayers and other individuals and organizations paying for health care are priorities. A model of ‘good prescribing’ has been proposed that has four aims (Barber 1995). These aims are to: maximize effectiveness, minimize risks, minimize costs and respect patient choice. Maximizing effectiveness is about selecting a drug therapy that will achieve its therapeutic objective in a suitable timescale. Minimizing risks is recognizing that all drug treatments carry an element of risk of causing harm to the patient and that selection of the drug should be about managing the benefits and risks. The cost of therapy should also be taken into account by the prescriber (see Ch. 19). Such consideration should go beyond a simple review of the drug costs to also consider any costs of monitoring treatment such as blood tests, the length of treatment and any additional items that could be required, such as prescribing an additional drug to protect the gastrointestinal tract from adverse effects caused by the first drug. Establishing the views of the patient is a vital part of the process of assessing the relative importance of the first three aims in this model. Patients may differ in their views regarding managing the symptoms of a condition, living with the consequences of a condition, exposing themselves to risks of harmful effects and the amount of money they would be willing or able to pay for treatment. In addition, patients may wish product selection to take their lifestyle into account such that the frequency and route of administration of the selected product fits in with their daily routine. It is accepted that ‘good prescribing’ involves trade-offs between these four aims and that this often involves delicate balancing between each of the aims.
The prescribing process will be considered under five headings, although there is some overlap between these and their sequence may not be the same in all cases. The first is concerned with all the things that must be in place before a prescriber can start to prescribe, the second with collecting information, the third with analysing the information and making the prescribing decision, the fourth with making appropriate records and plans for monitoring the patients progress; and the last with auditing and evaluating prescribing practice.
Prescribing can only be carried out by healthcare professionals with appropriate prescribing qualifications and these will vary depending on the type of prescribing to be carried out. To prescribe prescription only medicines (POM), either on the NHS or privately, the prescriber must have successfully completed training to allow them to act as a supplementary or an independent prescriber (Department of Health 2006). The training course consists of a taught element (around 26 days) and learning in practice (around 12 days), which includes prescribing under the supervision of a medical prescriber. To participate in a minor ailment scheme and prescribe pharmacy only medicines (P medicines) at NHS expense the pharmacist will likely have had to complete appropriate accreditation set by the local primary care organization.
Patients who are to receive their prescriptions from a supplementary prescriber must give informed consent. Patients do not need to sign this informed consent but it is good practice to make a note in the patient’s medical notes when informed consent was given. The exact nature of informed consent is difficult to define and it is likely that the input from the healthcare professional will vary between patients when obtaining consent. Observation of disputes between patients and physicians regarding whether informed consent was given shows that simply handing the patient a leaflet does not discharge the physician from their obligation to obtain informed consent. In any legal dispute it is up to the courts to decide which party they believe. However, the disputes that found in favour of the physician tended to be those where the physician was able to demonstrate that they had given the information to the patient because they had documented the advice they gave in the patient’s medical records.
Prior to the patient consultation the prescriber should ensure that they are suitably prepared. Part of this preparation includes ensuring they have sufficient indemnity insurance that covers their prescribing and that their job description clearly shows that prescribing is part of their role. Another part of the preparation is acquiring the appropriate knowledge and skills (Box 17.1).
Box 17.1 Checklist for knowledge and skills required by pharmacist prescribers
Independent pharmacists can prescribe any licensed medicine except controlled drugs and supplementary prescribers can prescribe any licensed or unlicensed medicine including controlled drugs provided it has been specified in the clinical management plan
It is vital that each prescriber prescribes only within their own area of competence. Knowing one’s own limitations is a key skill for a prescriber. In addition, they must also have an appropriate level of experience dealing with the condition and it might be appropriate to refer a patient presenting with a condition rarely experienced to another prescriber for assessment and any prescribing if required
The administrative arrangements regarding the prescribing process must be fully understood. In the case of minor ailment schemes, these arrangements could include a description of records that should be kept and how payment for the service is to be made. For NHS prescribing, the prescriber should be aware of the categories of patient that are exempt from NHS charges and what payments should be made by those that are not exempt
Pharmacist prescribers must maintain patient confidentiality and take steps to ensure that no unauthorized personnel can gain access to patient medication records by securely storing the data either via lock and key or via appropriate electronic security measures such as passwords for data stored electronically
Prescribers should be aware of the good practice guidance from the Department of Health and the Royal Pharmaceutical Society’s statements on prescribing in the Code of Ethics before they start to prescribe. This guidance addresses prescribers not prescribing for themselves, not normally prescribing for members of their family, and also covers accepting gifts and hospitality for suppliers
Prescribers must be aware of security issues surrounding prescribing and take steps to minimize the risks. Blank prescription forms could be used by drug misusers to try and obtain supplies of prescription medicines for abuse or to sell to others. Care must therefore be taken to ensure that the forms are securely stored. Personal security must also be considered if the prescriber is visiting patients in their own homes or other locations in the community
A pharmacist’s knowledge and skills required for the management of a therapeutic area must be up to date and based upon the best evidence available at the time. The knowledge should extend to non-drug approaches to treatment as sometimes these could be the most appropriate intervention
Prescribers should be aware of other professions they could refer patients to, e.g. general practitioner, the accident and emergency department in the hospital, dentists, the community nursing service (district nurses and health visitors), social services and self-help groups
Where possible, prescribers should familiarize themselves with the patient’s medical history prior to the consultation. Obviously this would not be possible in minor ailment schemes as patients are likely to arrive without an appointment and their medical notes will not usually be available to the community pharmacist.
During the consultation, prescribers must take a full history of the presenting condition and any other factors such as other conditions the patient has and any other medications, including over the counter medicines and complementary medicines, that the patient may be taking. It may be necessary to carry out further investigations such as measuring the patient’s blood pressure. This information must be recorded in the patient’s medical notes.
Before any prescribing can take place a diagnosis must be made. If the pharmacist is acting as a supplementary prescriber, the diagnosis will have been made by an independent prescriber, but the pharmacist should interpret the information obtained before and during the consultation to check that the patient’s diagnosis remains valid. Independent prescribers must establish a working diagnosis based upon the information they have gathered on the patient. At this stage it may be necessary to request laboratory tests such as urea and electrolytes, red blood cell count and haemoglobin tests to help confirm the working diagnosis.
With increasing complexity of health care and increasing specialization of the roles of healthcare professionals there is a growing need for different professions to work together. Pharmacists must ensure that they are aware of the different professions they could call on for support or to refer patients to. Examples of referrals include the patient’s general practitioner, the accident and emergency department in the hospital, dentists, the community nursing service (district nurses and health visitors), social services and self-help groups.
Where patient care is shared between healthcare professionals there is an obvious need for clear communication links, especially around monitoring and reviewing the patient’s therapy. Clear communication links are particularly crucial in supplementary prescribing where two different professions can prescribe for a patient. There must be a clear description of the criteria that would require the supplementary prescriber having to refer the patient back to the independent prescriber. Examples of such referrals could be failure of the patient’s condition to respond to the therapy outlined in the clinical management plan or the patient suffering an adverse drug reaction (ADR) to the prescribed medication. With supplementary prescribing, both independent and supplementary prescribers must have access to a common medical record.
Upon analysis and interpretation of the patient’s signs, symptoms and laboratory test results, the pharmacist prescriber must consider the treatment options, including the option of offering no treatment to the patient. The consideration of therapy options must include concurrent diseases and medication and the patient’s lifestyle (would the treatment regime fit in with the patient’s schedule or would side-effects of drugs affect their ability to perform their usual activities).
A key component of this phase is involving the patient in the decision making in order to achieve concordance. The prescriber must communicate the benefits and risks of the different treatment options to the patient or their carer. The principles of concordance dictate that patients should fully participate in the decision-making process, and a consultation style where patients are treated as equals and have the opportunity to ask questions and to raise any concerns or worries they might have is more likely to achieve this.
Following selection of the drug and its formulation, the dosage regime must be determined. The dosage guidance in the summary of product characteristics, British National Formulary or local and national clinical guidelines should be used to work out the dosage to be prescribed. In general, it is recommended that dosage be started at the lower end of the dosing schedule and that the dose should be gradually increased until the required therapeutic benefits are seen while minimizing side-effects. However, there are many exceptions to this, such as prescribing a loading dose for certain antibiotics or prescribing drugs where the therapeutic benefits are not obvious, such as drugs used in prophylaxis.
The prescriber must also indicate the quantity to be supplied on the prescription. The quantity to be supplied will depend upon whether the treatment is likely to be acute or chronic. If the treatment is acute then the quantity is likely to be enough for the recommended course of treatment. When determining the quantity to be supplied for a chronic condition, prescribers should bear in mind how often they would wish to review the patient, whether the patient has to pay for the item, the patient’s ability to pay the prescription levy and whether there are any dangers from accidental or deliberate overdose. In general, smaller quantities offer the opportunity to review patient’s therapy more frequently and reduce waste if patients are unable to take their medicine through the occurrence of troublesome side-effects or ADRs. However, smaller quantities can cause greater inconvenience as patients will have to visit their healthcare professional more frequently and will incur greater expense if they have to pay for their medication. Smaller quantities will also increase the prescriber’s workload as they will have to write more prescriptions.
It is important to realize that the responsibilities of the prescriber do not end with signing the prescription. The prescriber must make appropriate records of the medicine(s) prescribed and any advice given to the patient in the patient’s medical notes. For paper held records, the prescriber will obviously have to write the name of the prescribed item, the formulation, the strength and the dosage instructions in the notes. In the case of electronic prescribing the details of what was prescribed, the date of prescribing and the directions will be stored automatically in the patient’s records. However, there may be a need to record additional information such as when the patient should next be reviewed and the monitoring that is recommended.
All prescribing should be followed up with some monitoring although in some cases this may be left to the patient or carer to do themselves. Monitoring should address the anticipated benefits from therapy such as control of the patient’s symptoms and harmful effects such as the patient suffering from adverse effects. In many situations the patient or their carer will be given advice regarding what to do should the beneficial effects not materialize or if the harmful effects are troublesome. However, there may be situations where these are not apparent, such as monitoring blood cell counts following administration of a drug known to affect blood cell formation. These patients should be informed when they will next need to have their therapy reviewed.
Prescribers must appreciate any drug can cause an ADR, but that certain drugs are more likely to cause an ADR. Therefore, they must be aware of the action required if patients suffer from an ADR. Minor ADRs that are known to occur with established medicines do not need reporting while serious suspected and actual ADRs for new and established medicines and all ADRs for new medicines should be reported via the yellow card reporting scheme (see Chs 19 and 47).
Like all areas of practice it is important that prescribers reflect upon their practice and use their continuing professional development (CPD) to develop professionally. Prescribing audits and prescribing reviews can assist the process of reflection. The availability of prescribing reviews will depend upon the area of prescribing practice and, to some extent, the location. The collation and analysis of prescribing data in secondary care is the responsibility of the trust and there is great variability in the availability of such data.
All parts of the UK produce prescribing reports for primary care prescribing although different organizations are responsible for these reports in different parts of the UK and there will be differences in the types of report produced. The majority of the reports are concerned with medical prescribing which is, perhaps, not surprising considering doctors are responsible for the majority of prescribing activity. Non-medical prescribing reports are produced locally by primary care organizations and therefore subject to greater variation between different localities. Prescribing data include the number of items prescribed and the cost of prescribing. It should be noted that these data allow questions for reviewing prescribing practice to be formulated but very rarely ever provide answers. There are many reasons why prescribing figures can be skewed one way or the other. These can make it difficult to make comparisons between practices. Examples of factors affecting prescribing rates include above average numbers of patients living in residential or nursing care or a practice being located in an area with a higher prevalence of disease such as a former coal mining area. Prescribing data do not contain any patient-specific data so it is not possible to differentiate 10 items prescribed for 10 different patients and 10 items prescribed for a single patient. Prescribing data do not contain any drug indications, which can make it difficult to review the prescribing of drugs with several indications. There are usually major differences between the case mix of different professional groups, which makes comparing prescribing across professional boundaries a particularly difficult task.
Evidence-based medicine (EBM) has been described as ‘a means of closing the gap between research and everyday practice and ensuring that clinical decisions are based upon the best available scientific evidence’ (MeReC Bulletin 1995). It allows healthcare professionals to compare the evidence for different treatment options. This comparison may sound straightforward but unfortunately the available evidence is frequently of variable quality and different studies may use different methodology or may measure different aspects of health, which makes comparisons difficult.
The process of EBM involves four stages (Eccles et al 1998). The first involves identifying the question to be answered, such as: ‘Does treatment with drug X prevent more cardiovascular events than treatment with drug Y?’ The second stage involves searching the literature to find studies that have compared drug X with drug Y. The third stage is a critical appraisal of the studies that have been identified, which involves making judgments about the quality of the studies, comparing the evidence supporting drug X with that supporting drug Y and determining whether the balance of evidence favours one drug over the other. The final stage is applying the evidence to clinical practice, which could involve recommending one drug be prescribed by clinicians rather than the other.
Assessing the quality of the evidence involves comparing the studies reported in the literature (see Ch. 23). There is a hierarchy of type of studies in terms of quality with meta-analysis of more than one randomized controlled trial at the top, then single randomized controlled trials, then controlled trials without randomization, then descriptive or case control studies and finally reports from expert committees (Eccles et al 1998; see Table 17.1 for a description of these terms). A key point to note concerning the method used in the study is whether the study was double blind or not (double blind is where the researcher and the subjects did not know which treatments were given to the subjects). The review of a study should also consider whether there is a potential for bias in the study by considering who funded the study and the affiliations of the authors. It is important to review the doses of drugs used as some studies do not use equivalent doses of drugs, particularly where one drug is compared with a competitor’s drug. The reviewers should consider whether the study used healthy volunteers or patients suffering from the condition and whether the demographic profile of the subjects was similar to the general population. Generally, the larger the study, in terms of the number of subjects included, the higher the quality of the study. However, the number of subjects needed to show an effect is dependent on the magnitude of the effect, with larger numbers needed to demonstrate smaller differences between the different arms of the study. The length of the study is another important consideration. This should be related to how the drug will be used in practice as the benefits reported in a study lasting 10 days would have more relevance to a drug used to treat acute short-term conditions compared to long-term chronic conditions where the benefits could wear off after the study ends. The review should consider the endpoint reported in the study (what was measured in the study) and whether the endpoint was the same as the intended outcome (e.g. the intended outcome of a treatment in a study could be a reduction in the incidence of cardiovascular events but the endpoint used in the study might just address one risk factor for cardiovascular events).
Table 17.1 Studies investigating health care
| Type of study | Description |
| Meta-analyses | A statistical method of combining the results of more than one trial |
| Double blind randomized controlled trial (RCT) | A study where one group of subjects is randomly assigned to receive one treatment and the other group to receive an alternative treatment or placebo. Double blind is where neither the researchers nor the subjects are aware of which group they have been assigned to |
| RCT | A study where one group of subjects is randomly assigned to receive one treatment and the other group to receive an alternative treatment or placebo |
| Case control studies | A study that compares one group of patients with another |
| Cohort studies | A study that follows the progress of a group of patients (a cohort) and compares their progress to the characteristics of the group members |
| Expert opinion | A report from an expert committee or opinions expressed by a respected group of experts |
The evolution of modern medicines and appliances has resulted in a tremendous increase in the range of products available on prescription and a corresponding increase in the amount of information available to support their use. This vast array of information originates from many sources including the pharmaceutical industry, academic institutions, professional bodies, government agencies and patient groups. Much of this information is aimed at prescribers and other professional groups, but, with the increased availability of this information through advances in information technology and the upsurge of public demand, many patients also have greater access to information about medicines. With such a variety of sources all competing for the attention of the prescriber there is a danger that they could be overloaded with information of variable quality and which is potentially conflicting.
Reports of studies published in the literature can be obtained by using online resources and archives such as Medline, Embase or PubMed, although it is likely that most searches will result in large numbers of hits and reviewing the quality of such a large number of papers will be very time-consuming. Alternatively, there are several sources of evidence-based medicine reviews. The Cochrane Library is a collection of databases that contain evidence-based reviews and is available through the National Electronic Library for Health and University Libraries. Clinical Evidence from the BMJ Publishing Group provides a summary of the evidence available for managing a wide variety of conditions and includes an assessment of the quality of the evidence (see Ch. 23).
There has been a recent proliferation in the number of guidelines produced in developed countries to assist practitioners in a wide variety of clinical roles. They have been defined as ‘recommendations on the appropriate treatment and care of people with specific diseases and conditions’ (National Institute for Health and Clinical Excellence 2008). However, it should be noted that the foundations on which guidelines are based could range from guidance based on good quality evidence to those based upon expert opinion. The quality of guidelines can also vary and prescribers must decide whether a guideline is suitable for use in their practice. In addition, there are few, if any, guidelines that can provide guidance that is appropriate for 100% of patients. Prescribers should not follow guidelines blindly but consider in which situations the guideline should be used and those when it should not. If a prescriber decides to deliberately deviate from a guideline, they should document their reasons for deviation in the patient’s medical notes.
The National Institute for Health and Clinical Excellence (NICE) is an independent organization responsible for providing ‘national guidance on the promotion of good health and the prevention and treatment of ill health’ (NICE 2008). NICE provides guidance to support the management of a wide range of clinical conditions. The Scottish Intercollegiate Guidelines Network (SIGN) produces evidence-based clinical guidelines for use by people working in the health service and for patients.
Software is available that can assist the healthcare professional with diagnosis and prescribing. Relevant patient information such as the age, sex, symptoms 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.
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 general practices or one 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 of medicines. Formularies that span different 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 effectiveness, 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 the formulary such as the practice nurse, health visitors, district nurses and community pharmacists. In larger organizations it would not be feasible to include everybody in the formulary group. 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 non-formulary 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?).
The National Prescribing Centre (NPC) is an NHS organization 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’. The NPC has 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.