Research suggests that 237 million medication errors occur at some point in the medication process in England per year.

When errors occur in prescribing high-risk medications for older patients with multiple medical problems, there is a significant risk of serious harm. High-risk medicines are those which risk significant patient harm or death when used in error, such as warfarin.

Reference event

The reference event in this investigation is an incident where a hospital inpatient was administered repeated doses of warfarin in error and suffered significant harm as a result. The error was detected after six days by a ward-based clinical pharmacist.

Investigation summary

This patient safety investigation looks at the:

  • Systems and processes which underpin the identification, prescribing and administration of warfarin for older inpatients.
  • Main patient safety risks arising from the prescribing and administration of warfarin and other high-risk drugs.
  • Main patient safety defences that act to protect people from medication errors with high-risk medicines.

Download and read the full report.

Safety recommendations

We made three safety recommendations as a result of this investigation, to NHS England and NHS Improvement, the Royal Pharmaceutical Society, and the NHS Specialist Pharmacy Service.

We have now received responses, which are shared below.

NHS England and NHS Improvement

It is recommended that NHS England and NHS Improvement carry out work to understand and further define the work of hospital clinical pharmacy teams, including the period between initial medicine reconciliation and discharge, in consultation with relevant stakeholders.

NHS Specialist Pharmacy Service

It is recommended that the NHS Specialist Pharmacy Service should update its resource on the prioritisation of hospital clinical pharmacy services to facilitate the dissemination of developments in good practice and policy with respect to pharmacy prioritisation and the issues highlighted in this report.


Joint response from NHS England and NHS Improvement, and NHS Specialist Pharmacy Service

Your report identifies a recommendation for NHS England and NHS Improvement and another for the NHS Specialist Pharmacy Service (SPS). The NHS SPS is directly commissioned by NHS England and NHS Improvement, and so we have combined our response.

As you clearly identify, medicines safety is an important responsibility for every member of the hospital-based multidisciplinary team. Research has shown how much of an important role ward-based clinical pharmacy services play in helping to support the multidisciplinary team to identify and reduce medication errors.

Putting in place this approach has been the cornerstone of our work in hospitals since the inception of NHS England and NHS Improvement and there have been many productive improvements.

NHS England and NHS Improvement published The NHS Patient Safety Strategy in July 2019. As part of the strategy we incorporated our existing Medicines Safety Improvement Programme (MSIP) which had been set up in response to the 2017 World Health Organisation’s Third Global Patient Safety Challenge: Medication Without Harm.

The MSIP is ongoing, and will continue to focus on the most important causes of severe harm associated with medicines. This includes the prescribing of high-risk medicines such as anticoagulants and the optimisation of systems that improve the safety of processes.

In addition, we’re continuing our ongoing programme for the roll out of Electronic Prescribing and Medicines Administration Systems. By the end of 2021, this will provide electronic prescribing systems across 79% of acute, adult, in-patient medicines, reducing the likelihood of errors in prescribing.

Aligned with the work of these programmes, and in response to your findings which show ward-based clinical pharmacy provision in hospitals is varied, and that its important role in helping to address medication errors may not be fully understood, NHS England and NHS Improvement is now scoping an additional piece of work to define the work of hospital clinical pharmacy teams.

This will ensure we have the correct processes, support and guidance in place for medical and clinical staff in relation to the prescribing of high-risk medications.

The programme would include scoping the work to update the NHS SPS resource on the prioritisation of hospital clinical pharmacy services to facilitate the dissemination of developments in good practice and policy. To do this, we’re collaborating with internal professional and policy colleagues and a range of external stakeholders, including organisations representing those who provide hospital clinical pharmacy services.

Our key partner in this work will be the Royal Pharmaceutical Society, specifically its Hospital Expert Advisory Group, to ensure there is alignment with the work they’re planning in response to their recommendation.

The COVID-19 pandemic and ongoing vaccination programme continues to put the NHS under significant pressure. Nationally, our priority is to continue supporting this while restoring non-COVID-19 services for patients, and letting NHS staff to have the rest and recuperation they need.

NHS hospital clinical pharmacy teams of pharmacists and pharmacy technicians have played a pivotal role in helping to manage the impact of COVID-19 on patients and staff in hospitals for the past year. This includes working in multidisciplinary teams, focusing on the very complex matter of the safety of prescribing for COVID-19 patients, particularly in intensive care units, and playing their part in the deployment of COVID-19 vaccinations – and their contribution has been outstanding in every respect.

We believe that to carry out the scoping exercise, meaningful engagement with the service would best be undertaken from Spring 2021 at the earliest.

Updated response received 26 March 2021

Royal Pharmaceutical Society

It is recommended that the Royal Pharmaceutical Society, supported by NHS England and NHS Improvement, should provide guidance on models of hospital clinical pharmacy provision. The guidance should provide information on the models’ ability to enhance safety and healthcare resilience and include consideration of the appropriate skill mix and experience within the clinical pharmacy team.


The Royal Pharmaceutical Society welcomes HSIB’s report.

We are the professional body for pharmacy with a mission to put pharmacy at the forefront of healthcare, and our vision is to be the world leader in the safe and effective use of medicines.

Through our Hospital Expert Advisory Group we will work with the NHS to support the recommendations made, which we believe will reduce variability and underpin patient safety.

Clinical Ward pharmacy is an important part of the "safety net" in operation in hospital. In addition to improved understanding, definition and guidance on models of care, it is important to instil a culture where everyone constantly questions the medicines that are being prescribed and administered, and the reasons why.

We will develop professional guidance on models of hospital clinical pharmacy provision, to define the work of hospital clinical pharmacy teams.

Response received 16 December 2020


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