SALG was asked to justify  support for the removal of postoperative pain as an indication for modified-release opioids, based on the Public Assessment Report published in March 2025, and highlighted in the previous edition of the  Patient Safety Update (published May 2025). The correspondent requested evidence of patient harm when modified release opioid medications were used in enhanced recovery protocols following arthroplasty and caesarean section.

The response by the chairs of SALG, Dr Plaat and Dr Barclay is reproduced in abridged form below.

The letter explaining our position, including references for some of the evidence for the recommendation is available on the SALG website: https://www.salg.ac.uk/media/l3sjmffw/letter-to-mhra-opioid-stewardship-002.pdf 

CPOC has also produced a position statement on MR opioid use.

Guidelines from the USA, UK and Australasia all now advise against use of MR opioids for acute pain, including this publication from the FDA and the revised CDC guidelines for prescribing opioids for pain.

Below are some additional references regarding the risk of persistent post-operative opioid use. following prescription of modified release opioids:

Lam T, Xia T, Biggs N et al. Effect of discharge opioid on persistent postoperative opioid use: a retrospective cohort study comparing tapentadol with oxycodone. Anaesthesia 2023; 78(4): 420-31

Gong J, Beyene K, Yan Chan AH et al. Persistent opioid use after hospital admission due to trauma: a population-based cohort study. Pain, 2025; 166(1): e1-9

Shah A, Hayes CJ, Martin BC. Factors Influencing Long-Term Opioid Use Among Opioid Naive Patients: An Examination of Initial Prescription Characteristics and Pain Etiologies. J Pain 2017; 18(11): 1374-83:

In the context of enhanced recovery protocols, not only is there risk of dependence, but also a lack of evidence of benefit. You mention post operative LSCS and arthroplasty in your email, so we have focused on these two patient groups in our response.

As obstetric anaesthetists ourselves we were interested to read that some hospitals routinely prescribe modified release opioids to patients who have had a Caesarean section. The ​NICE guideline committee for Caesarean Birth¹ did not find evidence to support the use of modified release opiates.  ​Current NICE guidelines published in 2021 recommend paracetamol, NSAIDs and dihydrocodeine.  This was echoed by Roofhoft et al in the  PROSPECT guideline for pain management after elective Caesarean section,² ​ both NICE and PROSPECT encourage multimodal approaches to minimise post-operative opiate usage and enable it to be discontinued as soon as possible.

1. Caesarean birth NG192. 2021
2. Roofthooft E, Joshi GP, Rawal N, Van de Velde M. PROSPECT guideline for elective caesarean section: updated systematic review and procedure-specific postoperative pain management recommendations. Anaesthesia, 2021; 76(5), 665–80.

Regarding arthroplasty, below are links to European guidelines about pain management after arthroplasty from the PROSPECT Group, which is the group that generates evidence-based guidelines for the European Society of Regional Anaesthesia

1. Lavand’homme, P. M., Kehlet, H., Rawal, N., & Joshi, G. P. . Pain management after total knee arthroplasty: PROcedure SPEcific Postoperative Pain ManagemenT recommendations. EJA, 2022; 39(9): 743–57. Lippincott Williams and Wilkins.
2. Anger M, Valovski H, Beloeil P, et al. PROSPECT guideline for total hip arthroplasty: a systematic review and procedure-specific postoperative pain management recommendations. Anaes, 2021; 76(8), 1082–97.

Neither of these guidelines recommends the use of modified-release opiates.  Immediate release opiates are only recommended for rescue analgesia.