see also pain, analgesia and analgesics, opiates and opioids, alcohol dependency, drug dependency

• opiate Rx for pain relief may require modification in opiate-dependent patients but there is no cross-tolerance between opioids and most other drugs of abuse (eg. alcohol, benzodiazepines, cannabis, cocaine, amphetamines and thus altered morphine doses are not required in these non-opiate-dependent patients.
• remain open and non-judgemental, promote realistic expectations and set clear limits
• diagnose pain as for other patients
• exclude serious pathology such as epidural abscess or vertebral osteomyelitis / discitis presenting as back pain
• identify addictive disorder where possible, maintain high index of suspicion, consider drug use screening
• look for signs of drug use (intoxication, withdrawal, track marks, etc)
• if drug use identified, take thorough drug history - drugs used, Rx providers, comorbidities (eg. hep), psychiatric disorders
• assess degree of distress and contribution of psychosocial factors
• additional information from family & friends, usual prescriber or dispenser (to confirm current drugs/doses), regulatory authorities such as Medicare Prescription Shopping Program

• consult and collaborate with registered methadone or buprenorphine prescriber or dispenser, drug and alcohol service, pain specialist or psychiatrist
• communicate with patent's usual GP or drug and alcohol service
• consider early referral for interdisciplinary assessment & Mx
• Rx the painful condition (eg. splint fractures, drain abscesses, etc)
• use best practice guidelines where available, empasising non-opiate Rx (eg. chlorpromazine for migraine)
• maximise non-opiate analgesia
• use non-drug Rx (see above)
• consider tramadol, opiates and opioids, other adjuvants such as ketamine, clonidine (Catapres), anxiolytics, antidepressants, and anticonvulsants
• patients booked for elective surgery should have pre-op assessment at least 1wk before surgery to plan pain Mx
  • continue methadone up to surgery & post-op, replace parenterally if needed
  • planned naltrexone cessation may be required
  • no current consensus on whether buprenorphine should be ceased pre-op

• taking methadone invariably results in opioid tolerance and lower pain thresholds
• ensure usual dose of methadone is continued or replaced parenterally to prevent withdrawal
• contact registered methadone prescriber or dispenser to check correct dose
• in general, opioid-tolerant patients with post-op. pain require 2-3x more opioid than opiate-naive patients
  • thus commence with dose 50-100% greater than usual

• buprenorphine is a long acting (up to 72h) partial agonist of mu-opioid receptors which will oppose analgesic effect of opiates
  • thus maximise use of non-opiate analgesia, consider tramadol, local anaesthetic blocks & non-drug Rx

• naltrexone is a long acting (24-72h from oral dose, 3-6mths from implant) opioid receptor antagonist
• receptor antagonism can be overcome by high doses of opioids in a monitored environment
• cessation of naltrexone may cause increased opioid sensitivity and exaggerated response resulting in fatal resp. depression
  • in this scenario, use low dose opiates with extreme care, closely monitoring effect and titrating dose.