painmx_drug_dependent

Mx of acute pain in drug dependent patients

assessing acute pain in these patients

  • 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

Mx of acute pain in opioid addiction

  • 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)
  • 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

Methadone patients

  • 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 patients

  • 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 patients

  • 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.

Reference

painmx_drug_dependent.txt · Last modified: 2018/08/08 09:17 by wh