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“Independent prescribing is neither for the faint-hearted nor for those lacking experience as a pharmacist”

by Mark Tomlin, MSc, MRPharmS

UK pharmacists have been able to train as prescribers for several years. Here a consultant pharmacist for critical care describes the kind of interventions where independent prescribing comes into its own


Clinical pharmacists in hospitals have evolved from suppliers of medicines to advisers on the safe use of medicines and providers of evaluated information about drug therapies. Historically when pharmacists offer professional advice to hospital doctors they have required them to make the changes physically.

As experience increases and practice evolves many clinical pharmacists feel they are effectively dictating therapy changes to medical colleagues. Some pharmacists simultaneously explain the situation to the doctor, obtain approval and make the changes. Is this latest evolution assertive professional advice or a form of prescribing?

A prescribing qualification offers clinical pharmacists the facility to take this one step further by replacing professional advice with action that directly benefits patients. Supplementary prescribing is restricted by the need for a clinical management plan.

I believe independent prescribing is a more efficient tool than supplementary prescribing because it allows new situations to be managed quickly, dynamically and professionally.

In this article I describe how, as a pharmacist independent prescriber, I have been able to enhance the quality of patient care through improved prescribing.



In the critical care units at Southampton General Hospital, I review patients’ medication charts each weekday morning. Patients in this setting are often complex, with comorbidities, pre-existing conditions and changing diagnoses, and medicines need to be optimised for these patients individually. I am able to amend patients’ prescriptions without delay to correct errors or enhance safety.

To ensure effective team communication and education of junior doctors, medical staff members are informed about any changes at the next opportunity, often on the daily ward round.

To demonstrate the benefit of such interventions, I recorded my prescribing over three months (February to April 2008) on a hand-held digital device. The data were uploaded into Microsoft Excel and analysed for trends in what was prescribed and its contribution to patient care.


Prescribing trends

Over 56 working days I prescribed 128 items, comprising 30 different products for 69 patients. The most frequent item prescribed was parenteral nutrition (TPN), for which I am the main prescriber. During this time 84 bags of TPN were prescribed for 27 patients.

Excluding TPN henceforth, I made 44 prescribing interventions (events) for 42 patients, using 24 different medicines. Over half of these involved antibiotics and four involved anticoagulants — both of these notably high-risk groups of medicines.

Twelve of the prescriptions involved adjustment of vancomycin doses for individual patients. On several occasions I was able to ensure a new guideline for vancomycin — involving continuous 24-hour infusion — was used appropriately. This facilitated the education of junior doctors who were unfamiliar with this technique.

Eight out of 44 events related directly to therapeutic drug monitoring. Some involved pharmacokinetic calculations but mostly they were professional judgements about likely doses in response to blood levels or changes in renal function. Five prescriptions were for gentamicin dose modification.

As an example, one patient with endocarditis was being treated with 80mg twice a day, with a blood sample taken in the morning. When I reviewed the patient’s blood results, I found a rising creatinine and a high gentamicin level (2.9mg/L). I immediately suspended the gentamicin doses for that day, wrote a plan in the patient’s notes detailing further sampling, and continued to review the situation during the week. The patient was stabilised over the next few days without further deterioration in renal function.

Twelve of 44 prescribing events related to doses. Two thirds of these concerned dose modification due to changes in renal function. On three occasions allopurinol doses were reduced for patients with degrees of renal dysfunction. The doctors on duty were unaware that one of the metabolites of allopurinol (oxpurinol) is eliminated renally and toxic to the kidneys.

Early dose reduction can eliminate the risk of increased renal impairment. As a prescriber this can be dealt with immediately; for a clinical pharmacist without prescribing qualifications the doctor must be paged, the details of metabolism and toxicity explained, and the prescriber must then return to the ward and amend the chart in accordance with the pharmacist’s advice.

Four prescribing events related to selecting a more appropriate formulation for an individual patient (eg, changing pantoprazole tablet to lansoprazole orodispersible tablet to enable administration via nasogastric tube). In many cases junior doctors are unaware of the formulation of different products (and changing to a liquid product is not always possible).

On a separate occasion I identified a patient with a critically low serum phosphate level but with a potassium level of 6mmol/L. Because standard therapy with dipotassium hydrogen phosphate was inappropriate, I prescribed and supplied sodium glycerophosphate. Nursing staff were able to manage the situation quickly and the patient avoided potential harm through excess potassium.

On two occasions I believed the doctor’s prescription was unsuitable and prescribed an alternative. In one instance, a high-dose low molecular weight heparin (LMWH) had been prescribed for a patient with acute coronary syndrome whose renal function was less than 30ml/min.

LMWHs are eliminated renally and can accumulate in renal impairment. Because no factor Xa assays were available (to monitor the LMWH’s effect), and with antidotes only partially effective, the consequence of a bleed in such a patient would be severe. In line with trust guidelines I changed the prescription to an unfractionated heparin infusion.


Expanding roles

From intervention data (gathered over many years), it can be predicted that during the three months of this study, pharmacists could have made some 250 interventions or contributions to the care of patients in intensive care or high dependency areas at Southampton General Hospital.

This project only recorded 44 (non-TPN) prescribing events. It is therefore apparent that prescribing by clinical pharmacists is still a low frequency activity across a narrow (but expanding) range of medicines.

Designing guidelines is only part of the work of clinical pharmacists to improve patient care; implementing these guidelines is a major hurdle that can be overcome with the support of the pharmacist as a prescriber. It is also important to close the governance loop by designing safer systems of working and providing feedback to hospital doctors about errors that have occurred.

The main role of clinical pharmacists will remain the active contribution of information and advice when medicines are used. Nonetheless, prescribing offers a mechanism for efficiently translating this advice into action to the benefit of patients, doctors and nurses. It further integrates the pharmacist into the clinical team and maximises patient benefit from medicines. There are risks, but these can be managed with good communication and respect for colleagues’ roles.

This is only possible, however, when trust has developed through a good working relationship. Active participation of medical colleagues in the training of non-medical prescribers can help develop the trust that is needed. Accordingly, I believe prescribing courses for pharmacists should remain a post-graduate activity.

Drafting a proposed scope of practice is a valuable starting point in developing the dialogue with medical and nursing colleagues before commencing a prescribing role.

I believe it is good practice to first work as a supplementary prescriber to help understand the politics, negotiation and supervision required and to developing the right psychology for the new discipline.

Independent prescribing is neither for the faint-hearted nor for those lacking experience as a pharmacist.


Mark Tomlin is consultant pharmacist for critical care at Southampton University Hospitals NHS Trust.


Citation: Clinical Pharmacist URI: 10984737

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