AUTHOR: Marie Richardson
Marie Richardson is a Senior Pharmacist at Our Lady of Lourdes Hospital (OLOLH) in Drogheda. Marie holds an MPharm from the University of Strathclyde, has over 6 years hospital pharmacy experience, 15 years’ experience working in community pharmacy, has completed an MSc in Clinical Pharmacy from UCC and is currently undertaking an employment-based PhD with UCC, RCSI and OLOLH examining hospital pharmacist prescribing. She has collaborated with a multidisciplinary team alongside consultant anaesthetist Dr Fauzia Bano, consultant orthogeriatrician Dr Helen O’Brien and pain management CNS Gwyneth Mahoko in OLOLH leading to the development and use of post-operative analgesia prescribing guidelines.
Orthogeriatrician Dr Helen O’Brien and pain management CNS leading to the development and use of post- operative analgesia.
60 Second Summary
Post-operative analgesia is crucial in enabling patients to mobilise promptly, commence early rehabilitation, have a greater chance of returning to their pre-operative baseline and therefore better long-term prognosis.
Short-acting opioids are preferable to long-acting opioids in opioid naïve patients due to superior effectiveness in managing acute pain, reduced risk of respiratory impairment, and reduced risk of dependence, misuse and diversion. Short acting opioids should be charted both regularly and as required in the immediate aftermath of surgery. As acute pain subsides, the regular opioid should be weaned down and ceased followed by as required opioids.
Analgesia should be patient specific considering: age, weight, injuries, hepatic function, renal function and titrated to patient functionality and pain.
Post-operative nausea and vomiting, and constipation are very common post-operative side-effects. Patients should have at least one regular laxative prescribed if they are prescribed opioids, except in gastrointestinal surgery where the consultant general surgeon will determine if and when laxatives are needed. Anti-emetics should be prescribed considering the QTc interval, patient’s other regular medicines and if the patient has Parkinson’s disease.
NSAID’s are best avoided in older patients due to the increased risk of bleeding and acute kidney injuries.
Managing pain and associated issues in the post-operative setting
Most of us will undergo a surgical procedure at some point in our lifetime. These can be elective or acute procedures. However, with all surgical procedures, there can be some associated pain and other side-effects in the aftermath which needs to be carefully monitored and managed.
Post-Operative Pain:
Management of post-operative pain can have a significant impact on patient recovery and their long-term prognosis. Inadequate post-operative pain management can result in numerous avoidable consequences that can have a catastrophic impact on patients and their recovery as indicated in Figure 1 below.
Figure: Risk of adequate management of post-operative pain
Delays to early patient post-operative mobilisation has potentially the single greatest impact on the long term prognosis of the patient. Where the patient resides can also be affected: can they be discharged home or do they require additional rehabilitation or are they unable to reside at home independently in the future? All of this can understandably be very traumatic for patients and their families.
A further consideration is that it is predominantly older patients who present to our acute hospitals with orthopaedic injuries such as hip fractures which are generally the most prevalent acute orthopaedic presentation. Every single day a patient is immobile, approximately 4% muscle mass is lost. Most of our acute hip fracture patients tend to be older and frailer, therefore they cannot afford to lose any further muscle mass. To further emphasise the importance of early postoperative mobilisation of hip fracture patients, it has also been associated with reduced mortality.
If patients were to be immobilised unnecessarily, this will have a significant impact on their long term prognosis and their ability to actively engage with and undertake their rehabilitation program. In turn, this can reduce the likelihood of patients returning home or to their baseline mobility and living as active and as fulfilled a life as they did before their presentation to hospital.
In the elective surgical setting, it is now quite common for patients to undertake a prehabilitation programme i.e. they will be given exercises and advice before their surgical procedure to ensure good muscle tone. This has been shown to have a positive impact on patient mobilisation, recovery and prognosis. However, this is not an option for acute presentations.
Pain is cited as the main reason noted by physiotherapists for patients being unable to mobilise post-operatively. Therefore, if we can control and manage postoperative patient pain, we can have a significant positive impact on their prognosis and quality of life.
Work in OLOLH:
A multidisciplinary team in OLOLH including a consultant Anaesthetist Dr Fauzua Bano, consultant Orthogeriatrician Dr Helen O’Brien, Pain Management CNS Gwyneth Mahoko and Senior Pharmacist Marie Richardson worked to develop a post-operative prescribing guideline for the orthopaedic setting.
It is predominantly Non-Consultant Hospital Doctors (NCHDs) who prescribe in the post-operative setting. The goal was that a comprehensive guideline was available for NCHDs to consult, in order to safely and appropriately prescribe analgesia and associated medicines to manage pain and common post-operative side-effects.
Contra-indications to use, cautions in use, dosing guidance, agents in order of preference, dosage adjustments for older patients, and items that needed to be reviewed before prescribing were laid out under 6 distinct headings. The areas on the guideline included: paracetamol, NSAIDs, opioids, laxatives, gabapentenoids and anti-emetics.
Patient Specific:
In line with best practice and optimal patient care, analgesia prescribing should always be patient specific. Analgesia should consider the patient age, weight, renal function, hepatic function, subjective pain analysis, patient functionality, the type of procedure the patient has undergone, the nature of their injuries, if several pain inducing injuries are noted and any other medication the patient is prescribed.
To put this in context, the postoperative opioid needs of a 93 year old female patient, weighing 50kg, with mild renal impairment presenting with a hip fracture will be markedly different to 45 year old male patient weighting 110kg presenting with polytrauma from a traffic collision who has normal hepatic and renal function, no co-morbidities and no regular medication.
All analgesia prescribed should be carefully monitored, reviewed regularly and titrated to the individual patient requirements and functionality.
What is new in post-operative pain management:
The recommended management of post-operative pain has undergone significant changes in the last decade. Prior to this, it was acceptable to prescribe long-acting opioids in the post-operative setting. However, significant issues were arising globally due to misuse, dependence and diversion of long acting opioids.
In addressing this challenge, Hah et al published a paper in 2017 Levy et al published an editorial in 2018 indicating that long-acting opioids should be avoided in opioid naïve patients in the post-operative setting.1,2 An opioid naïve patient is a patient not routinely prescribed or taking opioids.
In 2020, it was followed by the publication of a multidisciplinary international general consensus guideline reinforcing earlier publications, offering clear, concise guidance on how to target the issues of opioid abuse as detailed above.3 Avoidance of long-acting opioids, setting realistic patient pain expectations, regular review and down titration of opioids to cessation,3 utilising only shortacting opioids and short-duration discharge prescriptions were offered as guidance on how to deal with the challenges.
The HSE issued a guidance document in January 2022 “GUIDANCE FOR OPIOID PRESCRIBING FOR ACUTE NONCANCER PAIN, POSTOPERATIVE PAIN AND POST-PROCEDURE PAIN” which sets out clear goals for opioid prescribing in this setting.4 The overall objective of the document is to avoid misuse, diversion and misappropriation of opioids. Furthermore, it indicated patient information and education should be provided about opioids and that unneeded opioids and medicine should be safely disposed of at their community pharmacy. It also recommends short-acting opioids are to be prescribed regularly and as required for opioid naïve patients, with a maximum 4 days’ supply of opioids on discharge prescriptions, patients should be down titrated as soon as possible and doses reviewed regularly.
Opioid analgesia is predominantly initiated in acute hospitals and discharge prescriptions are generally prepared by the most junior doctors for patient return to the community setting. It is important that prescribers are aware of this and prescribe safely and appropriately in order to help manage the issues of inappropriate opioid use.
Plan for management:
The WHO pain ladder has been the mainstay for a rational stepwise approach to pain management. The original ladder had 3 steps and solely focused on upward management of pain as it was originally formulated for the management of cancer pain. However, it was subsequently adopted as a tool for all pain management.
The latest version as detailed in Figure 2 has the addition of a fourth step for interventional treatments and is also bidirectional. This is particularly relevant for the management of acute post-operative pain where treatment starts higher up the pain ladder and is then titrated down as the patient recovers and pain levels reduce alongside their analgesia needs.5
Opioids:
Opioids are routinely required to manage acute post-operative pain. As detailed above, only short-acting opioids should be used in opioid naïve patients. However, age, renal function, other prescribed medicine and co-morbidities are also a significant consideration, especially for older patients. As we age, our ability to metabolise and excrete medicines naturally declines resulting in accumulation of medicines. This is more likely with long-acting opioids and can result in drowsiness, delirium, respiratory depression, confusion and hallucinations.
Short-acting opioids should be prescribed regularly and as required in the immediate aftermath of surgery. Doses should be as per individual patient requirements. Both the regular and as required doses should be reviewed regularly in the context of patient functionality and pain, and titrated to the individual patient needs.
In accordance with Figure 2 above,6 the analgesia prescribed should be reduced, and titrated down as the patients pain reduces and correspondingly their need for opioid analgesia. Patient’s in the acute post-operative setting would usually commence on strong opioids or step 3 of the WHO pain ladder.5,6
Oxycodone:
OxyNorm® should be prescribed for regular administration four times per day with additional as required doses charted. The as required doses are crucial for administration approximately 30 minutes before physiotherapists approach the patient and enhance mobilisation and rehabilitation and ultimately ensure optimal pain management and therapeutic outcomes. They can also be administered if needed in between regularly prescribed doses.
Morphine
It can be administered either as Sevredol® 10mg tablets or Oramorph® liquid and should be prescribed as four times a day for regular administration with additional as required doses if needed.
Tapentadol:
Palexia® FC tablets can be prescribed three times a day for regular administration with additional as required doses charted.
Opioid metabolism and excretion:
Due to the predominant renal metabolism of opioids, dose reduction may be necessary for patients with renal impairment who are prescribed morphine or oxycodone. However, tapentadol should avoided in patients with severe renal impairment.
Opioid weaning and tapering:
To ensure the safe and effective management of opioids, it is recommended to gradually reduce the regular dose before discontinuing it when appropriate. Additionally, it is important to reduce as-needed doses along with regular short-acting opioid doses and keep them charted for possible future use.
When stepping down to step 2 of the WHO pain ladder and utilizing weak opioids such as tramadol and codeine,5 it is necessary to exercise caution and consider their relative potencies compared to morphine as indicated in Figure 3 below.
Although patients can be reduced to tramadol or codeine products caution should be exercised with older patients. Tramadol can interact with other medicines such as SSRI’s and SNRI’s to increase the risk of serotonin syndrome and seizures. It can also cause drowsiness, mood changes and dizziness.
Paracetamol:
Paracetamol is the most commonly prescribed analgesic and is on the first step of the WHO pain ladder.5 It is very well tolerated and can be prescribed for oral, intravenous or rectal administration. However, consideration of patient weight and hepatic function must be made prior to prescribing. If a patient is <50 kg, the dose should be reduced to 15mg/kg.
Hepatic function should always be reviewed by prescribers. If the patient exhibits elevated liver function tests (LFTs) indicating impaired ability to metabolise medicines hepatically; paracetamol dosing should either be reduced or alternatively not prescribed to avoid further deterioration of hepatic functionality.
Non-Steroidal Antiinflammatories (NSAIDs):
NSAID’s would be a rational choice for use in patients post-surgery to reduce pain and inflammation in accordance with the WHO pain ladder. However, they should not be routinely be prescribed to older patients for long periods of time due to:7
• Older patients are at naturally higher risk of bleeding due to their age, but this risk is exacerbated by the common prescribing anti-platelets and anti-coagulants in this patient group.
o Additionally, non-selective NSAID’s increase the risk of bleeding 4 fold, while selective NSAID’s increase the risk of bleeding 3 fold.
o Regular use of NSAIDs has been found to increase the mortality rate for gastrointestinal bleeds to 21%, in contrast to the 7% mortality rate observed in patients who do not take NSAIDs.
• Risk of acute kidney injury is doubled within 30 days of commencement of an NSAID
• All NSAIDs double the risk of hospitalisation due to heart failure
• Increased blood pressure, fluid retention and increased risk of fatal cardiovascular events
If NSAID’s are required for older patients in the post-operative setting, they should be prescribed for a short period of time and always prescribed with a proton pump inhibitor. Low dose as opposed to maximum doses is also preferable.7 In community pharmacy, regular OTC purchases of NSAID’s should be borne in mind.
For younger patients, NSAID’s can be routinely used. However, consideration should be given to their co-morbidities, medical history and other medications prescribed. As with older patients short-term NSAID use with coprescribing of a proton pump inhibitor is preferable.
Laxatives:
Reduced mobility relative to presurgery mobility is normal. This can increase the risk of constipation in its own right. However, in the post-operative setting, patients are routinely prescribed opioids to manage post-operative pain which commonly cause constipation. This can be uncomfortable and potentially debilitating for patients and reduce their ability to mobilise thereby impeding rehabilitation. Bowel motion is routinely monitored on surgical wards.8
With this in mind, patients should be prescribed at a minimum one regular laxative if they are prescribed an opioid. The only exception is patients who have undergone gastrointestinal surgery. In this instance laxatives should only be prescribed on and in accordance with the explicit instructions of the consultant general surgeon.
Lactulose should always be prescribed and administered regularly to ensure effectiveness. Movicol® and senna are also commonly used in this setting. Phosphate or Microlax® enema’s can be prescribed for as required use.
Gabapentenoids:
Post-surgery, certain patients may encounter neurological pain, based on the complexity of the procedure. Gabapentin and pregabalin are potential treatment options that can help manage this type of pain. It is important to note that these medications, like opioids have a high likelihood of being misused leading to misappropriation and dependence. Careful monitoring of their use is essential to prevent any adverse consequences.
When they are prescribed, they should be initiated and used at the lowest effective dose for the shortest period of time necessary. For instance, gabapentin 100mg three times a day or pregabalin 25mg three times a day prescribed regularly only.
They should be reviewed regularly and ceased when appropriate. It is also prudent to exercise caution when prescribing these agents to older patients, as they may be more susceptible to orthostatic hypotension symptoms.
Anti-emetics:
Post-Operative Nausea and Vomiting (PONV) is a common issue for patients. It can be a side-effect of anaesthesia used during the surgical procedure and can be very prevalent in the first 24 hours post-surgery. PONV is also a common side-effect of opioids which are routinely prescribed in this setting.9,10
PONV is very unpleasant and uncomfortable for patients. It is especially important patients are prescribed an anti-emetic at a minimum on as required basis for the first 24 hours post-surgery to ensure they can rest and recover from the procedure. They should be prescribed separately for oral and/ or intravenous administration. It is often advisable that post-operative anti-emetics remain charted as required for the duration of their hospital admission.
However, the choice of anti-emetic must consider the patient’s comorbidities, other medications prescribed and QTc interval.
Parkinson’s Disease:
Parkinson’s disease is a neurodegenerative condition leading to motor symptoms such as tremors, bradykinesia, rigidity, and postural instability due to depletion of dopamine in the substantia nigra of the brain. 15,000 people are currently affected by Parkinson’s disease in Ireland, however as it is the fastest growing neurodegenerative condition, we can anticipate seeing more patients with this condition.
It is treated by administration of medicines that act on the dopaminergic neurological system to aid stimulation of the dopamine receptors in diverse ways:
a) levodopa a precursor of dopamine.
b) dopamine receptor agonists e.g. pramipexole and rotigotine.
c) monoamine oxidase B inhibitors e.g. rasagiline.
Nausea and vomiting are mediated in part by the release of dopamine and the activation of dopaminergic pathways in the gastrointestinal tract and chemoreceptor trigger zone. This in turns stimulates the vomiting centre. Several anti-emetics exert their effects by antagonising the dopaminergic pathway.
However, given the aetiology and treatment of Parkinson’s disease as detailed above, anti-emetics whose pharmacological actions are mediated via the dopaminergic pathway should be avoided in patient with Parkinson’s disease due to drug-drug interactions which may lead to impaired control of Parkinson’s symptoms.11
The anti-emetics of choice in Parkinson’s disease are:
a) domperidone
b) ondansetron
c) cyclizine
Heart Failure:
Cyclizine should be avoided in heart failure or acute myocardial infarction as it can cause a reduction in cardiac output.9)
QTc interval:
Many anti-emetics can prolong the QTc interval. Furthermore, patients are commonly prescribed other regular medication, which they may have been taking pre-admission, which can also cause QTc prolongation. There is an additive effective of adding an additional QTc prolonging medicine to a patient’s medication regimen.12
Common medicines which can prolong the QTc interval includes* citalopram, escitalopram, amitriptyline, amiodarone, clarithromycin, lithium, haloperidol, ivabradine, ranolazine, venlafaxine, tolterodine and sotalol.
*Note this is not an exhaustive list of QTc prolonging medicines; check medicine SPC’s and interaction resources for information.
When we examine commonly prescribed anti-emetics; domperidone, ondansetron, prochlorperazine and metoclopramide, they can all potentially cause QTc prolongation.9 They should therefore not be prescribed to patients who have a prolonged QTc on ECG or if a patient is already prescribed another agent which could prolong the QTc interval. Cyclizine prescribed intravenously and/ or orally is preferred in this instance.
Conclusion:
Acute post-operative pain management plays a pivotal role in promoting patient mobilisation. This in turn has a significant impact on the patient’s longterm prognosis, quality of life and their ability to return to their pre-operative baseline. Short-term use of short-acting opioids as regular and as required analgesia is preferred to avoid dependence, misuse and misappropriation.
The orthopaedic post-operative prescribing guideline in OLOLH, has led to a notable 30% improvement in post-operative mobilisation of patients as noted by our orthopaedic physiotherapists.
Whilst prescribing analgesia correctly and safely is a significant part of post-operative care, other common side effects must also be managed to ensure patient comfort and expedite recovery.
References available on request
