Careful liaison between the patient and care teams is necessary for appropriate prescribing and safe management of opioid medication for symptom control. A risk assessment of prescribed drugs and dispensed quantities and frequencies should be agreed and documented in the patient record.
Be mindful that underprescribing could influence people to seek non-prescribed substances. There may be reluctance by either the patient or clinicians to start opioid medication because of previous experience or stigma. Concerns should be sensitively addressed.
Symptom control should be assessed on an individual basis and discussion with specialist palliative care is encouraged. There should be regular clinical review.
Medication-assisted treatment (MAT)
- Always confirm a patient’s MAT dose with pharmacy or substance use services and inform them of any inpatient admission or prescription changes.
- Substance use services may aim to stabilise MAT rather than reduce it.
- MAT should continue as advised by substance use services and should not routinely be titrated for palliative symptom control.
- Treat the MAT as a separate prescription not involved in symptom management or breakthrough dose calculation.
- Opioids should be started and titrated as they normally would for symptom control. In some circumstances, larger opioid doses may be required but the degree of tolerance is variable and difficult to predict.
- Controlled drugs can often be dispensed in instalments several times a week alongside the patient’s usual MAT to avoid dispensing large quantities at once.
- An NHS Scotland fact sheet comparing methadone and buprenorphine for opioid dependence provides further information.
- Naltrexone is an opioid-receptor antagonist that may be used as an adjunct to prevent relapse in patients with a history of opioid or alcohol use disorder. It should be stopped as soon as possible in patients requiring opioid analgesia. Suboxone is an oral preparation which has a combination of buprenorphine and naloxone. The naloxone in this preparation is not active orally and is there to prevent misuse via injection. Opioid therapy introduced after discontinuation of naltrexone requires careful monitoring. There may be initial tolerance whilst naltrexone is on board followed by opioid sensitivity as it wears off. Seek specialist advice.
Specific considerations for methadone MAT
- Methadone is usually given as an oral liquid 1mg/1ml for MAT.
- Doses are taken daily and may be dispensed daily. Some patients have supervised consumption at a pharmacy.
- Typical doses for methadone MAT are 60–120mg/day.
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Missed doses
If 3 or more oral doses have been missed for any reason, contact substance use services for advice on the reintroduction dose. Usual practice is to give 50% of the previous dose and retitrate.
Loss of oral route
If the oral route is not available, methadone (10 mg/ml injectable preparation) can be administered as a continuous subcutaneous infusion (CSCI) under the guidance of specialist palliative care. Usual practice would be conversion to a CSCI of methadone at 50% of the daily oral dose. This should be diluted in 0.9% saline and administered via a syringe pump, without any other drugs, over 24 hours.
Where CSCI is not appropriate or possible, Methadone can be administered at 50% of the daily oral dose split into twice daily subcutaneous bolus injections. Seek specialist advice if considering this.
Practice points
- Methadone can prolong the QT interval. Care should be taken when adding other QT-prolonging drugs.
- Methadone dose may require a 50% reduction where eGFR falls below 10 mL/min or the patient is in hepatic failure.
Specific considerations for buprenorphine MAT
- Buprenorphine MAT is available in different forms including:
- Daily sublingual dose (eg Subutex)
- Daily sublingual combined with an opioid antagonist (eg Suboxone)
- Daily oral lyophilisate dose (eg Espranor)
- Depot subcutaneous injection weekly or monthly (eg Buvidal)
- Buprenorphine MAT is typically used at higher doses (eg 12–24 mg/day) than buprenorphine in the palliative care setting which may result in antagonism when other opioids are required.
- Antagonism is unlikely with daily doses of under 8 mg.
- If Buprenorphine MAT is reduced or withdrawn, the opioid dose for analgesia may need to be reviewed and down-titrated as antagonism wears off.
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Missed doses
Because of the long half-life, patients can miss 2–3 days of buprenorphine before they become symptomatic of withdrawal.
If 3 or more doses have been missed contact substance use services for advice on the reintroduction and dosage.
Loss of oral route
If the oral route is lost when using oral buprenorphine MAT, liaise with substance use services for advice on the most appropriate alternative opioid and route of administration.
Practice points
- A switch from buprenorphine MAT to methadone MAT guided by substance use services could be considered if antagonism is a concern.
- Titration of short-acting opioids to the desired analgesic effect in those treated with buprenorphine might require higher doses. This should be discussed with specialist palliative care and closely monitored.
- Where opioid analgesia is required alongside buprenorphine MAT, opioids with a high µ opioid receptor affinity, such as fentanyl and alfentanil, may be more effective. Use of these opioids should be discussed with specialist palliative care and may be limited by local guidelines and availability.
- Buprenorphine may require dose reduction where eGFR falls below 20 mL/min or the patient is in hepatic failure.
Breakthrough medication
Titration of the background opioid is preferred, with immediate-release preparations of opioids (‘breakthrough doses’) best kept to a minimum..
The MAT dose should not be used when calculating the appropriate breakthrough dose for symptom control.
Multiple breakthrough dose usage may represent inappropriate use or undertreated pain.
Adjuvant therapies
Non-opioid analgesics should be considered as adjuvants when appropriate, but not as substitutes for strong opioids.
There is potential for misuse of adjuvants, especially gabapentin and pregabalin. Amitriptyline has less potential for misuse but can be harmful if taken in excess.
Non-pharmacological interventions such as radiotherapy, surgery and regional anaesthetic techniques should be considered.
Anxiolytics
Where clinically indicated, consider the use of benzodiazepines and seek advice from specialist palliative care. Benzodiazepines are usually introduced cautiously and titrated as required. There may be a degree of tolerance if there is a history of non-prescribed use, but this can be difficult to predict.
Where non-prescribed benzodiazepine use is confirmed or highly suspected consider regular benzodiazepine prescription for inpatients to prevent withdrawal.
Benzodiazepine withdrawal may present as insomnia, sleep disturbance, intrusive thoughts, panic attacks/anxiety, muscle stiffness, sensory disturbance, dizziness, palpitations, hallucinations, delirium or seizures.
Care around dying
When a person is felt to be in the last days of life, take-home naloxone intended for opioid overdose may not be appropriate as it could reduce analgesia. Discuss the potential removal or dose reduction of naloxone with substance use services/palliative care. Patients and carers may require guidance around this, including when and who to call for help. Refer to local services available.
If the oral route is lost, recently consumed substances may be replaced to avoid withdrawal. This may include the use of parenteral benzodiazepines and opioids.
Trauma, challenging social circumstances and mental ill-health frequently experienced by people who use drugs may increase the risk of terminal agitation.
Other considerations
The rules about medication use in certain institutions, such as prisons or homeless units may impact management. Through liaison, solutions should be be facilitated on a case-by-case basis.
Scottish Palliative Care Guidelines
