Prescribing Safety Assessment Series Session 5 Calculation Skills

Topic: Calculation Skills
Presenter: Dr Sona Petrosyan
Feedback & Certificate: https://app.medall.org/training/feedb...
Description: This session will cover Calculation skills: Section 5 of the Prescribing Safety Assessment Blueprint.

Read more: https://mindthebleep.com/prescribing-...

Q1&2 have been removed due to discrepancies

You may find the following helpful in regards to palliative care prescribing, breakthrough doses and dose increments of morphine:

1. Please refer to the Prescribing in Palliative care guidance section in the BNF. There is a table in there that has Equivalent doses of opioid analgesics [for example codeine, tramadol, morphine, oxycodone etc] if you are asked to convert from one formulation to another. There are also tables in this guidance to help convert from a total daily dose of morphine to a fentanyl or buprenorphine patch.

2. In terms of breakthrough doses, the Prescribing in Palliative Care guidance in the BNF recommends the following: If pain occurs between regular doses of morphine [‘breakthrough pain’], an additional dose [‘rescue dose’] of immediate-release morphine should be given. An additional dose should also be given 30 minutes before an activity that causes pain, such as wound dressing. The standard dose of a strong opioid for breakthrough pain is usually one-tenth to one-sixth of the regular 24-hour dose, repeated every 2–4 hours as required [up to hourly may be needed if pain is severe or in the last days of life].
- As an example, If someone was on 30mg BD MR morphine, their total dose would be 60mg.
- Breakthrough dose would be 6mg -10 mg [1/10th to 1/6th of total daily dose]

3. In terms of dose increments of the background MR morphine, the guidance suggests: the number of rescue doses required and the response to them should be taken into account; increments of morphine should not exceed one-third to one-half of the total daily dose every 24 hours.

Some approaches to this include:
1. Calculate the total daily morphine dose by adding the regular dose to the number of breakthrough doses and giving this in 2 instalments of MR morphine
- for example, total MR dose = 60mg, pt received another 20mg in breakthrough doses — increase to 40mg BD MR
2. Increasing the regular MR morphine by 30-50%
— for example, regular MR morphine is 60mg, pain still not controlled — new dose can be between 80mg and 90mg daily.

If you do some research on the internet, there seems to be varied approaches to the above.

It would be sensible in practice to go with whatever option gives the lower dose increase and monitor the patient closely.

As an FY1 or even senior, I would recommend contacting the palliative care and pain nurses to review your patient and provide guidance on what to prescribe - they are a valuable member of the team and experienced in this field and will be able to assess the patient in an individual basis and advise accordingly.