Tool to calculate estimated dose equivalences of oral morphine to other oral opioids

Samantha Owen, Principal Pharmacist Critical Evaluation and UKMi Medicines Q&A Lead, Southampton Medicines Advice Service, University Hospital of Southampton NHS Foundation TrustPublished

Use our tool to obtain approximate dose equivalences of oral morphine to other oral opioids and help you calculate an estimated equivalent dose

Refer to our full advice first

If you’ve not done so already, refer first to our full advice on morphine and opioid switching included in this series.

About the tool

Use our tool to calculate an estimated equivalent dose of oral morphine to other oral (non-morphine) opioids for pain management in adult cancer/palliative care patients.

Important note: the dose you calculate may not be the final dose recommended for your patient. You may need to apply a dose reduction – check whether this applies in our full advice on morphine and opioid switching.

The tool uses approximate potency equivalences obtained from a variety of information sources, including manufacturers’ data, specialist references, and published medical literature, to provide equivalence information for morphine and a selection of the more commonly prescribed oral opioids used in cancer and palliative care.

To convert from a non-morphine oral opioid to oral morphine, you will need to multiply the total daily dose of oral opioid by its potency equivalence, and to convert from oral morphine to a non-morphine oral opioid, you will need to divide the total daily dose of oral morphine by the potency equivalence for the oral opioid you are converting to.

The tool is not suitable for clinical settings other than palliative cancer care pain in adults, and is not suitable for routes of administration other than the oral route.

Select whether you're switching from morphine to a non-morphine opioid; or from a non-morphine opioid to morphine.

Medicines selection

To switch from oral morphine to an oral non-morphine opioid, select the non-morphine oral opioid you're switching to.

To switch from a non-morphine oral opioid to oral morphine, select the non-morphine oral opioid you're switching from.

Conversions

Divide the total daily dose of morphine by 0.1 to obtain an equivalent dose of codeine.

Divide the total daily dose of morphine by 0.1 to obtain an equivalent dose of dihydrocodeine.

Divide the total daily dose of morphine by 5 – 10 to obtain an equivalent dose of hydromorphone.

Divide the total daily dose of morphine by 1.5 – 2 to obtain an equivalent dose of oxycodone.

Divide the total daily dose of morphine by 0.3 – 0.8 to obtain an equivalent dose of tapentadol.

Divide the total daily dose of morphine by 0.1 – 0.17 to obtain an equivalent dose of tramadol.

Multiply the total daily dose of codeine by 0.1 to obtain an equivalent dose of morphine.

Multiply the total daily dose of dihydrocodeine by 0.1 to obtain an equivalent dose of morphine.

Multiply the total daily dose of hydromorphone by 5 – 10 to obtain an equivalent dose of morphine.

Multiply the total daily dose of oxycodone by 1.5 – 2 to obtain an equivalent dose of morphine.

Multiply the total daily dose of tapentadol by 0.3 – 0.8 to obtain an equivalent dose of morphine.

Multiply the total daily dose of tramadol by 0.1 – 0.17 to obtain an equivalent dose of morphine.

Example oral opioid switch from morphine to oxycodone

Use our example scenario to help you understand how to apply the tool in clinical practice.