NPSA dosing guidelines

Q.         What are NPSA guidelines?

A.         In 2007 the National Patient Safety Agency (NPSA) issued ‘Patient Safety Alert 18’ which contained a set of recommendations aimed at increasing the safety of warfarin dosing.

In section 8 the guidelines state:

“Patient and carer groups have informed the NPSA that warfarin regimens with the following characteristics would promote safer use:

• use the least number of tablets each day;

• use constant daily dosing and not alternate day dosing;

• not require the use of half tablets – patients find it difficult to break tablets in half and instead, when necessary, would rather use 0.5mg tablets.

The NPSA recommends that NHS organisations should review their local practice to

incorporate these characteristics. All strengths of warfarin tablets should be used to best meet the needs of individual patients. Not all patients will need all strengths of tablets.

It is recommended that oral anticoagulant doses should be expressed in mg and not as the number of tablets.”

Read the full guidelines at [ARCHIVED CONTENT] Actions that can make anticoagulant therapy safer: Alert and other information (nationalarchives.gov.uk) select document titled 'Anticoagulation Compliance Checklist'

Q.         How does INRstar incorporate the NPSA dosing guidelines?

A.         INRstar complies with the NPSA guidelines by adopting the following rules when calculating a suggested warfarin dose:

·         All warfarin doses (greater than 3.0mg/day) are rounded to the nearest 0.5mg. This ensures that the dose of warfarin will be the same for each day of the week.

·         All strengths of warfarin tablets (including 0.5mg) are made available for use in calculating dosing schedules.

·         Split tablets are excluded from suggested dosing schedules

Q.         I don’t like the guidelines. Can I turn them off?

A.            Yes, you can switch the guidelines on or off at any time for individual patients.

To disable the NPSA guidelines for an individual patient:

·         Click on the ‘Clinical Details’ tab in the patient’s treatment plan

·         Click the ‘Edit Treatment Plan’ button

·         Uncheck the ‘ Use NPSA Guidelines’ box in the ‘Tablet Selection’ section

·         Select the warfarin tablet strengths you prefer for the patient

·         Click ‘Save’

 Q.         Can I prevent the NPSA guidelines from being the default dosing method for new patients?

A.         Yes, The default dosing method for new patients can be configured by the organisation clinical lead to prevent NPSA dosing being applied as the default dosing method. See Help files for further information on this.

Q.         How does INRstar round the warfarin doses?

A.         If NPSA dosing is enabled, when a new INR result is added INRstar will calculate a new INR dose and then apply rounding to the dose as follows:

·         For in-range INR results the existing warfarin dose will be rounded to the nearest 0.5mg

·         For a low INR result the new suggested dose will be rounded up to the nearest 0.5mg

·         For high INR result the new suggested dose will be rounded down to the nearest 0.5mg

Note: Dose rounding will not be applied to doses less than 3.0mg/day

Q.         Why are low doses not rounded even if ‘Use NPSA guideline’ is selected?

A.         For low doses (<3.0mg) rounding to the nearest 0.5mg could cause proportionately excessive dose changes which might lead to under or over anticoagulation. For this reason doses of <3.0 mg are not rounded even when NPSA dosing is enabled

Q:         Since migrating from an earlier version. INRstar is changing the doses of some patients with in-range INR results. Why is this?

A:         Previous versions of INRstar did not apply rounding to doses when an in-range INR was entered. This did not fully meet the NPSA recommendation so this been changed in the latest version. This will mean that, if you have recently migrated from an earlier version and you have NPSA dosing enabled, you will notice that some warfarin doses will rounded to the nearest 0.5mg even if the new NR is in-range

Q:         Since migrating from an earlier version. INRstar is reducing the review period to 28 days for some patients with in-range INR results. Why is this?

A:         If INRstar changes the existing dose of a patient with an in-range INR result (by rounding it – as described above) it will also limit the associated review period to a maximum of 28 days. This is a safety precaution to prevent a patient having an excessively long review period following a change in the warfarin dose. This will only apply to patients with previous review periods which are greater than 28 days – and will apply to this treatment only.

Q.         We don’t use 5mg strength warfarin tablets at our centre. Can I prevent these being used?

A.         Yes, You can prevent the use of 5mg strength tablets whilst still using the NPSA dosing guidelines.

·         Click on the ‘Clinical Details’ tab in the patient’s treatment plan

·         Click the ‘Edit Treatment Plan’ button

·         Uncheck the ‘ 5mg tablet strength’ box in the ‘Tablet Selection’ section

·         Click ‘Save’