Prescribing tips - How to start an opioid
Information on how to initiate and titrate an opioid, and ongoing management
Titrating an opioid
Preventing opioid side-effects
- For patients with normal renal and hepatic function, start with a low dose (eg, morphine 20-30mg per day [10-15mg sustained release every 12 hours or 5mg immediate release every 4 hours] with 5mg immediate release rescue doses 1 hourly as needed for breakthrough pain
- For elderly or frail patients, the starting doses should be halved
- Advise the patient to seek health care professional advice if 3 consecutive rescue doses have not relieved pain
- Patients with severe, unstable pain should be reviewed frequently until their pain is controlled. Increase the regular dose until there is adequate relief, taking into account the use of rescue (breakthrough) doses.
- When stable analgesia is achieved, the opioid requirement over a 24 hour period can be estimated. This should be converted to the equivalent dose of a long-acting preparation, either as a once or twice daily dose depending on the medication used, to provide background analgesia.
- Patients should always be prescribed a short-acting rescue opioid medication to use for breakthrough pain alongside the long-acting (background) opioid.
- Regular laxatives must be prescribed when starting regular opioids, and the patient should be educated about managing constipation.
- Nausea and drowsiness can be a problem at first, and antiemetics may initially be required, but most patients rapidly become tolerant to these symptoms.
- In the case of nausea and vomiting, bowel obstruction, or difficulty swallowing, use the subcutaneous route.
- In renal failure - use lower doses and increase the dose interval to at least six hours. Observe carefully for side effects, especially drowsiness, respiratory depression, or myoclonus, until a safe dosage regime is established. Consider opioids which accumulate less in renal failure (hydromorphone, fentanyl).
- Counsel about driving issues associated with opioid use - especially during the titration phase or after rescue doses have been used.
See Assessing Fitness to Drive
- Regularly assess and treat opioid side effects (especially constipation).
- Regularly review the effectiveness of the current analgesics and number of rescue doses required, and adjust the background dosage accordingly.
- Educating patients about pain management, their opioids and side effects can improve compliance and analgesia.
See Patient Information - Overcoming Cancer Pain
- Providing written information or encouraging the use of a pain diary may be very helpful.
See Patient / Caregiver resource - Pain diary
- Ensure the patient has access to a breakthrough at an effective dose.
- Pre-emptive doses of pain relief can be given half an hour before an activity which usually causes pain may prevent incident pain. Offer this in addition to regular background pain relief.
- Use caution in up-titrating analgesics if the reason for extra rescue doses is incident pain, and if rescue doses are taken pre-emptively. If these patients are comfortable at other times, increasing their background dose may not be needed.
- Patients who are bedbound or in a residential care facility may need a planned rescue dose charted for 'prior to nursing care or procedures'. Ensure it is being given 20-30 mins prior to the care activity.
- Reasons why opioid switching may sometimes be needed include:
- Severe renal failure
- Adverse effects thought to be due to a particular opioid
- If a change in route of administration is required
- Problems with large volumes needing to be given orally or subcutaneously.
- Published guidelines for opioid conversion are based on estimates, often from single dose studies rather than chronic use, and there is also significant inter-individual variation
See EviQ Opioid Conversion Calculator
- Different conversion factors may be used in different settings
- Equianalgesic tables should only serve as a guideline to estimating equivalent opioid doses
- Clinical judgement should always be used, and doses must be titrated to both pain and side effects
- Frequent assessment of the patient is required to ensure a safe opioid switch.
Assessing fitness to drive - Medical standards for licensing and clinical management guidelines
The national guidelines provide general advice about prescription drugs and driving (see section 4.8.1). The specific advice about opioids is:
There is little direct evidence that opioid analgesics such as hydromorphone, morphine or oxycodone have direct adverse effects on driving behaviour. Cognitive performance is reduced early in treatment, largely due to their sedative effects, but neuroadaptation is rapidly established. This means that patients on a stable dose of an opioid may not have a higher risk of a crash. This includes patients on buprenorphine and methadone for their opioid dependency, providing the dose has been stabilised over some weeks and they are not abusing other impairing drugs. Driving at night may be a problem due to the persistent miotic effects of these drugs reducing peripheral vision.
Ref: Austroads. Assessing Fitness to Drive [Internet]. 2015 [updated 2015; cited 2015 Mar 05].
Last updated 17 February 2020