Primary Care Pharmacy March 2000 Vol 1 No 2 p37-39

Medicines resource management

Formularies in primary care

By Lee Furniss MSc, MRPharmS

Some practical aspects of setting up a primary care formulary are considered in this article

Formularies are lists of medicines to which prescribers are encouraged or required to adhere, depending on the type being considered.¹ For example, the Dental Practitioners' Formulary² is a list of the only medicines that dental surgeons are able to prescribe on the National Health Service (NHS) and adherence is compulsory. This is similar for the newly introduced Nurse Prescribers' Formulary² and one hopes that in the not too distant future there will be a "pharmacists' formulary". Formularies, as they are traditionally thought of, have their origins in secondary care and were originally produced to encourage hospital doctors to prescribe from the selection of drugs contained therein. Some hospitals require doctors to adhere to the medicines in the formulary more strictly than others. It is this type of formulary that the remainder of the article will consider, with specific reference to general practitioners (GPs).

Advantages of formulary development

It has been stated that the main reason for developing a formulary is to promote rational prescribing and to limit costs.^1,3 However it should be noted that rational prescribing might lead to increased drug costs (eg, the use of lipid-regulating drugs in the secondary prevention of coronary heart disease). Furthermore, the cheapest drug in a class may not always be considered the drug of choice. It is clear that cost and quality are inextricably linked. Evidence that the quality of prescribing improves after the introduction of a formulary is limited but there are a number of studies that show cost savings.¹ Cost is particularly important now because primary care groups (PCGs), and the Welsh and Scottish equivalents, have a cash-limited prescribing budget. PCG pharmacists and health authority prescribing advisers have access to Prescribing Analyses and Cost (PACT) data, which can help them to make informed decisions.
The construction of a formulary allows GPs in a practice to focus on their prescribing. GPs can reflect on their prescribing patterns and discuss therapeutic issues with their colleagues. The pharmacist can act as a facilitator and provide an objective view - they are ideally placed to chair such meetings. The pharmacist has access to a number of publications that may be used to promote evidence-based decision making, for example, the British National Formulary (BNF), MeReC Bulletin and Drug and Therapeutics Bulletin. There may be a need to appraise critically primary research that is presented by GPs. Such studies as these should include patient groups with characteristics seen in general practice, and outcome measures should be clinically relevant rather than being surrogate markers of disease. Recruitment of a keen GP within the practice can help to move the whole process forward.
Formulary meetings are an ideal educational opportunity for GPs and this continuous professional development can help to contribute towards the clinical governance drive of a practice. The meeting of GPs in this way may take place within a group practice or between groups of single-handed GPs within a geographical area.
A formulary allows the GP to develop an intimate knowledge of a limited range of medicines, which may allow enhanced monitoring of drug therapy and improved patient care. Patients also receive a consistent choice of drugs from partners within a practice and this can add to their confidence in the prescribing process. The formulary informs locums of the preferred medicines that are used within the practice, although the locum may be more familiar with different choices and potential conflict may occur.

Disadvantages of formulary development

The process of formulary development is inherently time consuming. It may be useful to decide to cover a limited number of major areas initially and to ensure that the meetings are short and focused. With acute prescribing (eg, of antibacterials), the effects of the formulary can be immediate. It may be wise to target areas of high-cost or high-volume of prescribing; fine-tuning can take place at a later stage. Here the provision of PACT data is invaluable. formularies take time to develop - Rome was not built in a day.
There may be difficulty in achieving agreement between GPs. Many factors affect choice of drug therapy and pharmaceutical company representatives may influence those GPs working in single-handed practices more than those working in group practices.⁴ The pharmacist can play a vital facilitative role and provide the sound evidence base on which to make decisions. If agreement cannot be made then differences should be accepted;³ formularies are not definitive and some flexibility should be allowed.
When writing some formulary areas, specialist advice may be needed. The local hospital formulary may prove useful or the PCG pharmacist may be able to utilise the local drug information centre. Furthermore, it has been estimated that up to 40 per cent of primary care prescribing may be influenced by secondary care. This emphasises the importance of joint working with local hospitals and the need for the PCG to have some input into both the hospital drug and therapeutics committee and the local area prescribing committee. The setting up of a joint primary/secondary care formulary will largely be dependent on the motivation and collaboration of local GPs and hospital doctors. This is the ideal towards which those involved in formulary development should strive.

Some practical issues

The first step in formulary provision is for everyone involved to agree that it is a good idea. The GPs involved should have ownership of the process and the medicines included. The GP is an independent contractor and is under no obligation to prescribe from the range of medicines within a formulary.
It is usual to arrange medicines into therapeutic categories but there are also other ways of arranging them. For example, the practice may find a disease orientated approach more useful (eg, management of respiratory tract infections). First- and second-line drug choices can be included. As with any support tool, it should not be assumed that the formulary will cover all prescribing decisions. However, there should usually be upward of 80 per cent concordance with the formulary. This allows a GP to maintain clinical freedom to treat a patient as an individual and allows for existing patients to remain on "non-formulary" medicines when it is considered inappropriate to change their existing therapy. The needs of a particular practice population should be considered. For example, a practice with a relatively high proportion of Afro-Caribbean patients may need a wide range of antihypertensives in its formulary because their blood pressure may not be controlled by usual first-line choices.
Formularies are often paper-based but with the development of electronic prescribing systems, access to the formulary at the point of prescribing seems to be the way forward. Similar systems have been in place in some hospitals for a few years. The electronic BNF has a formulary feature and GP prescribing systems are now developed with an option to attach a formulary. For the non-computerised practice, the paper version will prevail for the moment but it is important to find ways to prevent it from being left on a shelf gathering dust.

Drug choice in formulary development

The ideal properties of medicines included in a formulary have been described as:

• Effectiveness
• Safety
• Appropriateness
• Pharmaceutical form
• Cost⁵

Maintenance and monitoring of formularies

Updating and monitoring a formulary is probably as time consuming as setting it up but this process is crucial. Concordance with the formulary can be monitored using PACT data and this is a vital way of ensuring that the GPs do not go back to prescribing drugs that they preferred before the development of the formulary. New drugs are being introduced constantly and they should be carefully considered using the methods described above.

Conclusions

The formulary has traditionally been a way of attempting to rationalise the large number of drugs available and to help control costs. The pharmacist is ideally placed to co-ordinate the development of a local formulary. It should be acknowledged that there is a general move to the production of treatment guidelines, with the argument that drugs should be considered within the overall management of a disease process.⁷ There are pros and cons of having each but it has been suggested that the two are complementary, as in the PRODIGY system.¹ Indeed it can be argued that a collection of a number of treatment guidelines which stipulate drug choices is in fact a formulary. In the current NHS, the need to consider clinically- and cost-effective prescribing is imperative if a PCG is to manage its prescribing budget. The development of a formulary requires prescribers to consider their choice of drugs and is an opportunity to engage GPs in the prescribing debate. Rationalisation of drug choices may enable disinvestment in one therapeutic area so that resources may be deployed in another. Ultimately the development of primary care trusts will allow resources to be shifted between budgets.

Mr Furniss is a liaison pharmacist for North Islington primary care group, London

References