Switching insulins
Individuals maintained on insulin may need to switch product. The process of switching insulin products may introduce additional risks associated with insulin use.
Establishing the clinical need to switch insulins, choosing an alternative insulin and associated monitoring is an individualised clinical decision. The choice of insulin product depends on the indication, the relative properties of the available insulins, patient-specific parameters and response. This article focuses on insulin product factors which, following this clinical decision, should be considered during the switching process to support safe use. Patient-specific factors, such as dexterity, and clinical factors such as monitoring requirements following the switching process are not covered in this article.
Planned switches
Planned switches, due to a clinical need, are typically initiated and overseen by specialists. A planned switch allows for comprehensive clinical assessment, patient education and device training, and close monitoring and dose adjustment.
Unplanned switches
Often driven by supply shortages or unavailability of an individual’s usual insulin, unplanned insulin switches may bypass critical clinical checks. This substantially increases the risk of dosing errors, inappropriate product selection and consequent patient harm.
Biosimilar switches
An increasing number of individuals may be switching insulin products as a result of national or local initiatives to utilise insulin biosimilars. Implementation of biosimilar insulin switching is explored in our webinar Primary care discussions: biosimilar insulin (SPS page).
Our guidance Understanding biological and biosimilar medicines (SPS page) defines biologic and biosimilar medicines, as well as their regulation and interchangeability.
Device considerations
Insulins are available in different formulations using various device types. Switching without considering the device used for delivery can leave patients unable to deliver the intended dose.
In addition to device considerations, the individual needs of the person living with diabetes should be taken into account, including whether the device is appropriate for their manual dexterity.
Dose steps
The term ‘dose step’ refers to how an insulin dose (in units) is selected on a pen device. While older devices delivered insulin in 1-unit dose-step increments, some newer high-strength pens use larger increments (for example, 2 units). There are also formulations aimed at paediatric patients that deliver 0.5-unit dose increment.
If the specific device’s dose-step functionality is not taken into account, accurate delivery of the prescribed dose may not be achievable. The Summary of Product Characteristics (SPC) for the insulin product can be used to determine the device functionality and ensure the prescribed dose is achievable.
Volume of insulin
Some pens of the same insulin strength or same brand may contain different fill volumes and therefore contain a different total amount of insulin. If the device type and volume are not accounted for during an unplanned switch, the insulin supply may be depleted sooner than anticipated, which could lead to missed doses.
Compatibility
Where a reusable device is used, any new insulin supplied must be compatible; failure to do so will prevent accurate dose delivery, potentially leading to loss of glycaemic control.
Failure to consider device compatibility may lead to unsafe practices such as withdrawing insulin from a pen or cartridge device using a needle and syringe. This can lead to extra manipulations of the injectable, which increases the risk of dosing errors and contamination.
The BNF has information on reusable hypodermic insulin injection pens. Manufacturer guides can also be referred to for compatibility information.
Consumables and sundries
Failure to supply or provide access to necessary consumables and sundries (such as pen needles or sharps bins) when switching to a new insulin product or device means patients may be unable to administer their insulin or may lead to unsafe practices.
Switching strength
Switching to another strength of the same insulin brand does not require a dose adjustment, because pen devices count and deliver units of insulin, irrespective of product strength.
When switching between insulin products of different strengths, harm has been reported when the dose has been mistakenly halved or doubled in an effort to compensate for the supply of a different strength product.
Communication
Failure to effectively communicate the insulin brand, device and strength or to update patient‑held records, particularly when undertaking an insulin switch or during transfers of care, can lead to outdated or incorrect information being used. This increases the risk of the wrong insulin being prescribed, supplied, or administered.
Insulin is often prescribed ‘as directed’ in primary care to support dosing flexibility within an agreed individualised plan. Failure or inability to adequately communicate the prescribed dose range and insulin management plan may increase the risk of incorrect insulin doses being prescribed or administered.
Involvement of people living with diabetes
Failure to involve the individual using insulin, or their carers, in the switching process may result in them being supplied with insulin that they are unable to use and may to dosing errors or omissions.
If a person is not suitably trained or is unable to use the new device (for example, due to dexterity issues), this may result in incorrect or missed doses.
Shared decision-making can support the safer use of insulin following a switch. After establishing that an insulin switch is necessary, and agreeing the new insulin regimen, a strategy for planning when to switch and subsequent monitoring should be decided in conjunction with the person living with diabetes.
Mitigate risks associated with switching
Organisations and systems can take actions to support healthcare professionals in undertaking insulin switches.
Standardise clinical practice
Rationalise and standardise the range of insulin products routinely used and included in local guidelines, formularies and prescribing systems to reduce confusion between different brands, strengths and devices. Provide information on insulin strengths and devices, including compatibility for reusable devices, device volume and product-specific ‘dose steps’.
Ensure local clinical guidelines, protocols and formularies are consistent in the indication and place in therapy for biosimilar insulin products. Guidance should be provided on how to switch to these, ensuring patients are engaged through shared decision making.
Awareness and knowledge
Ensure healthcare professionals responsible for the prescribing and supply of insulin are aware of the risks associated with insulin product switches and key considerations to support safer use.
Review prescribing and supply processes to ensure individuals using insulin, or their carers, are adequately informed about any switch to a new insulin product, including the need to update any patient-held materials.
Digital systems
Review and utilise electronic prescribing functionality, including ensuring that prescribed doses can be delivered as an appropriate ‘dose step’ from the specified insulin device.
Device and sundries
Ensure processes are in place to guarantee access to all necessary compatible consumables and sundries when insulin is used and supplied. When switching to a new product consideration should be given to ensuring appropriate quantities are supplied.
Documentation and communication
Ensure clear documentation and communication of brand name, strength and device type at prescribing and during all transfers of care. Systems should ensure the prescribed dose range and insulin management plan are communicated and accessible for all parts of the care pathway.
Ensure all patient‑held documentation accurately reflects any change in insulin product or regimen to support safe ongoing use.
Associated resources
Further guidance on strategies to improve insulin safety across systems, including standardisation of clinical practice and upskilling of healthcare professionals can be found on our page Developing insulin safety across a system (SPS page).