GS - Palliative Care Calculations Flashcards
What are some First Line opioids and their uses?
Codeine (either alone or combined with paracetamol in co-codamol) is a weak opioid which may be
suitable for certain patient groups with moderate to severe pain.
Morphine is the first line strong opioid that should be used when managing severe pain. It can be given orally and is available in both immediate and modified release formulations (often abbreviated to I/R and M/R respectively on drug prescriptions). Morphine can also be given as a single bolus dose by subcutaneous (SC), intramuscular (IM) or intravenous (IV) route or added to a syringe driver which delivers analgesia slowly by infusion over a 24-hour period.
Diamorphine is not commonly used in palliative care in Scotland but may be first line in other countries. It is not available in an oral formulation. It is, however, useful if the patient requires 24-hour analgesia via a syringe driver and has reached more than 180mg SC Morphine in 24 hours. Diamorphine is more water soluble than morphine and therefore smaller volumes are required. This is particularly helpful when the required dose of injectable morphine would be too large a volume to be comfortable for the patient.
What are some Second Line opioids and their uses?
Oxycodone is useful if morphine is not tolerated and can be given orally, SC and IV.
Fentanyl is useful for topical application (as patches) in patients with severe, stable pain and in patients who have difficulty swallowing oral medication. As it can take a few hours to reach maximal analgesic effect it is not useful for those patients experiencing severe acute pain. Fentanyl tends to be less constipating and more appropriate for patients with renal impairment. It is also available as an injection (reserved usually for use in intensive care or during surgery) and buccal/sublingual/nasal formulations – see below.
What are some Third and Fourth Lines opioids and their uses?
Third- and fourth-line opioids;
These include alfentanil, methadone, buccal/sublingual/nasal fentanyl (for breakthrough cancer pain under specialist advice only).
What is the standard dose of a strong opioid for breakthrough pain ?
The standard dose of a strong opioid for breakthrough pain is ROUGHLY one-sixth to one-tenth of the regular 24-hour dose, repeated every 2–4 hours as required – this is subject to inter-patient variability so should be tailored to the individual. Dose conversions should be conservative, and doses are usually rounded down.
What should we monitor when giving a patient opioids and in what patients?
Any drug/dose/formulation/route adjustments should be monitored closely; taking extra care if patient is frail, elderly or has renal / hepatic impairment.
A 75 year old patient with newly diagnosed colorectal carcinoma is being reviewed by his palliative care nurse specialist. He is complaining of abdominal pain for which he is taking 5mg of immediate release oral morphine only – this helps at the time but wears off quickly. He has used six of his 5mg doses in the past 24 hours. He is not getting good background pain relief and in discussion with his GP, the nurse specialist advises starting 12-hourly modified release oral morphine.
- What total dose of morphine is he using in 24 hours?
Answer - 6 doses of 5mg =30mg
A 75 year old patient with newly diagnosed colorectal carcinoma is being reviewed by his palliative care nurse specialist. He is complaining of abdominal pain for which he is taking 5mg of immediate release oral morphine only – this helps at the time but wears off quickly. He has used six of his 5mg doses in the past 24 hours. He is not getting good background pain relief and in discussion with his GP, the nurse specialist advises starting 12-hourly modified release oral morphine.
- What dose of oral modified release (M/R) morphine will you prescribe, morning andnight?
The patient needs to get better background analgesia as the immediate release (I/R) version is not lasting long enough so giving the M/R version will help. Total daily requirement (30mg) can be given as two 12- hourly modified-release doses = 15mg in the morning and 15mg at night. This is prescribed as modified release (M/R) morphine and each dose should last 12 hours.
Prescription would look like this: Morphine M/R 15mg tablets orally twice daily.
This will help improve background pain, though consideration should be given to also prescribing a small dose of morphine for breakthrough pain - this would be approximately 5mg “if required for breakthrough pain” and patient’s response and requirement for breakthrough doses monitored closely.
A patient is taking oral morphine modified release (Zomorph®) 30mg twice daily and requires some breakthrough analgesia, for example when they are transferring from the bed to have a shower.
What dose of oral immediate release morphine should be prescribed?
Total dose of oral morphine being taken is 60mg in 24 hours.
From the guided study we read that breakthrough dose should be between 1/6 to 1/10th of the 24 hour dose, with careful monitoring of patient’s response.
Acceptable answer would be either 5 – 10mg if required. Reasoning:
If we choose 1/6 of dose (60mg) = 10mg.
The prescription would look like this: Morphine I/R 10mg orally if required for breakthrough pain.
If we choose 1/10 of dose (60mg) = 6mg. However it is easier to administer oral morphine in multiples of 5mg so can round down to this and monitor patient response.
The prescription would look like this: Morphine I/R 5mg orally if required for breakthrough pain. Whether we choose to 5 or 10mg would ultimately depend on age and renal function of patient – if more elderly choose 5mg - then review response.
A patient has been taking morphine modified release (MR) (Zomorph®) 60mg 12-hourly plus a total dose of 40mg of oral immediate release (IR) morphine tablets (Sevredol®) in 24 hours for breakthrough pain. They are now unable to swallow and reaching the end of their life. To make the patient comfortable the patient is to be switched to a subcutaneous morphine infusion over 24 hours, via a syringe driver.
How many milligrams of morphine should be added to syringe?
Patient on total of 120mg oral Morphine M/R (in form of Zomorph) + 40mg oral Morphine I/R (in form of Sevredol) in 24 hours = 160mg total oral morphine dose.
Using table in guided study we see that converting from oral to subcutaneous route requires dividing by 2.
160mg oral morphine divided by 2 is equivalent to 80mg subcutaneous morphine over 24 hours.
The patient should be closely monitored for efficacy and toxicity of the drug.
A patient has been taking morphine modified release (MR) (Zomorph®) 60mg 12-hourly plus a total dose of 40mg of oral immediate release (IR) morphine tablets (Sevredol®) in 24 hours for breakthrough pain. They are now unable to swallow and reaching the end of their life. To make the patient comfortable the patient is to be switched to a subcutaneous morphine infusion over 24 hours, via a syringe driver.
What dose of injectable (by sub-cutaneous route) morphine should be prescribed for any breakthrough pain if needed?
The 24 hourly dose is 80mg by subcutaneous route. Breakthrough doses are approximately 1/6 to 1/10 of 24 hour dose. As before the dose we choose will depend on age and renal function of patient but let’s estimate our initial choices then we can review response after a few doses:
If we choose 1/6th of dose = 80mg/6 = 13mg.
It is easier to measure morphine in multiples of 5mg so suggest could round down to 10mg if required and monitor response.
If we choose 1/10th of dose = 80mg/10 = 8mg.
Suggest could round down to 5mg and monitor patient.
A patient is taking 80mg modified release morphine, 12-hourly. Although their pain is quite well controlled, they are experiencing some unpleasant side-effects from the morphine. It is decided to switch them to oxycodone orally in modified release (M/R) tablet formulation.
What dose of oxycodone M/R orally should be prescribed every 12 hours?
Patient on 80mg oral morphine M/R twice daily.
From table in guided study, to convert oral morphine to oral oxycodone divide by 2.
So this is equivalent to 40mg oral oxycodone M/R every 12 hours. Patient should be closely monitored when any switches are made and dose adjusted accordingly.
A patient is taking 80mg modified release morphine, 12-hourly. Although their pain is quite well controlled, they are experiencing some unpleasant side-effects from the morphine. It is decided to switch them to oxycodone orally in modified release (M/R) tablet formulation.
If this dose of oxycodone had to be switched to a subcutaneous infusion of oxycodone in a syringe driver, what dose would you prescribe over 24 hours?
Syringe drivers contain sufficient drug for 24 hours so we need to work out 24-hourly dose by subcut route. The patient is currently on 40mg M/R Oxycodone 12 hourly – giving a total daily oral dose of 80mg. From the second part of table in guided study, converting from oral to SC route for oxycodone requires division by 2.
Answer is 40mg oxycodone S/C in syringe driver over 24 hours.
