opiate and opioid dependence

see also:

• Addiction medicine - drug and alcohol - main index and links
• opiates and opioids
• opiate antagonists eg naloxone (Narcan), buprenorphine, naltrexone
• methadone
• pain, analgesia and analgesics

• comes as white or brown powder which is usually heated on a spoon and then injected or smoked
• 10 points = 1 g
• most users use 1 point at a time
• even 1 point a day is likely to lead to withdrawal symptoms on cessation
• 3 points per day is significant use, 5-10 points a day is very high use
• has a relatively short half life, patients presenting with opioid intoxication may self recover in time and without pharmacological intervention
• risk of fatal overdose due to respiratory depression is increased if the patient uses a higher amount than their tolerance and/or if mixed with other substances such as alcohol
  • this is usually readily treated with naloxone - either intranasal, IM or IV

• heroin injecting commenced in Australia in the late 1960's
• by 1997, it was estimated there was ~70,000 heroin-dependent persons with a rapid increase over the past few years associated with cheaper heroin
• deaths from heroin overdose has increased from 6 in 1964 to 600 in 1997 and 737 in 1998
• HIV / AIDS remains under good control amongst heroin injectors but ~11,000 cases of hep C in 1997 were attributed to sharing of injection equipment
• heroin dependency is a poorly understood, chronic relapsing condition
• mortality is 1-2% per year which is ~15 times that for similar age & sex population
• a UK study in 2005 showed that of those that took heroin “regularly” at less than 3x per week, on average it took 9 months for them to become physically dependent and use it daily. The actual time for physical dependence depended on a complex interaction of social factors (eg. living with a dependent person accelerated dependence), personality and context in which people use the drug. None became instantly addicted, some took as little as 5-6 months, while others took 5 years before becoming physically dependent.

• reduction in deaths
• reduction in morbidity - hep C, hep B, HIV, bacterial infections (abcesses, SBE), non-fatal overdoses
• improvement in mental health

• improved relationships & parenting
• reduction in crime
• increased employment
• improved residential status (ie. less homelessness)
• increased education & training
• reduction in all sorts of drug usage
• reduction in heroin use

• earning income legally, or social security
• less debt
• benefits outweigh costs to individuals & society

• most is provided in residential care but outpatient detox. is increasing, though not all are suitable or willing for this approach.
• relapse is common and should not be cause for despair, but should be Rx by further detox. or other Rx forms ASAP.
• usual detoxification is a combination Rx of (this can also be used for inadvertent naltrexone usage causing withdrawal):
  • see Mx of opiate withdrawal
  • IV fluids
  • anti-emetic:
    • prochlorperazine (Stemetil) 12.5mg i.v., repeat once if no effect
    • ondansetron 4mg i.v. if prochlorperazine ineffective
  • clonidine (Catapres):
    • helps ameliorate some of the more distressing symptoms of heroin withdrawal
    • dose: 75-150 mcg orally when vomiting controlled, or up to 300mcg i.v. titrated to effect (monitor BP)
    • if cease clonidine abruptly may get rebound hypertension
    • lofexidine is similar but with less CVS adverse effects but not available in Aust. yet.
  • paracetamol (acetaminophen):
    • for bone pain
  • diphenoxylate or lomotil:
    • for diarrhoea
  • hyoscine:
    • for abdominal cramps
    • dose: 20mg slow i.v. titrated to effect
  • benzodiazepines:
    • for short term Rx of insomnia
    • eg. midazolam 5mg i.v. boluses titrated to effect or oral diazepam as symptoms settle
  • if uncontrollable delirium, then consider:
    • rapid sequence induction anaesthesia, usually using propofol infusions

• Ultra Rapid Opiate Detoxification (UROD)
• Rapid Opiate Detoxification (ROD)
• both currently experimental and require general anaesthesia or heavy sedation.

• methadone:
  • an opioid agonist which is well absorbed orally with a long half-life allowing once daily dosing
  • introduced in Australia for Rx of heroin dependence in 1964
  • pts attend a clinic or pharmacy each day to be given a supervised dose
  • detoxification is not required for pts starting methadone
  • psychosocial interventions are an important adjunct
  • as many as 85% will stay on methadone for 12mths & most require Rx for at least 2 yrs
  • pts retained in Rx on a larger dose & for a longer duration generally achieve better results
  • optimal dose is 60-100mg/day
  • important Rx factors include optimal dosing & the morale of clinic staff
  • programs are not available in the NT
• naltrexone:
  • see opiate antagonists eg naloxone (Narcan), buprenorphine, naltrexone
  • a long acting opioid antagonist which is well absorbed orally
  • a severe withdrawal reaction may be precipitated if the pt has recently taken heroin or another opioid
  • thus should not be started until 7-10days after last opioid dose
  • dose: usually 50mg per day
  • best results are obtained with “motivated” pts (eg. white-collar professionals, persons on parole, probation or in jail)
  • if it is taken intermittently & then heroin is taken in the intervening periods, the risk of death from overdose may be INCREASED due to the reduced opioid tolerance.
  • has also been found useful to decrease craving in chronic alcoholics undergoing withdrawal treatment
• buprenorphine:
  • see opiate antagonists eg naloxone (Narcan), buprenorphine, naltrexone
  • a partial mu agonist and weak kappa antagonist taken sublingually as it has a high 1st pass metabolism
  • half-life 4-5hrs
  • ceiling effect:
    • because it is a partial agonist, its effects plateau at higher doses & then begins to behave more like an antagonist which limits its maximal analgesic & resp. depression effects
    • this confers a high safety profile clinically (better than methadone) although deaths have occurred from overdoses
  • the high affinity blockade significantly limits the effect of subsequently administered opioid agonists or antagonists
  • results are comparable to methadone
  • can be taken on alternate days
  • more expensive than methadone but may become Rx of choice
  • pts on large doses of heroin may experience some withdrawal symptoms
  • dose regimen:
    • 8-12mg sublingually daily for 5-7 days then maintenance dose 4-32mg/d will suppress symptoms of withdrawal & reduce illicit opioid use. Dosing can be extended to every 2-3 days.
  • acute overdose:
    • naloxone may be helpful in improving resp. depression although improvement in mental state may be less. Doses of 5-10mg may be needed.
• leva-alpha-acetylmethadol (LAAM):
  • a methadone derivative with longer half-life allowing alternate day dosing
  • maybe available in Australia soon
• sustained release oral morphine (SROM):
  • few studies; a trial has commenced in Australia in 2000;
• prescription heroin:
  • has been available in UK since 1926 but has not been well studied.
  • results might be comparable to methadone & a Swiss study in late 1990's showed impressive results
  • may have a place in users refractory to other Rx
• non-pharmacologic Rx:
  • examples:
    • drug-free outpatient counselling
    • residential rehabilitation
    • self-help groups (eg. Narcotics Anonymous)
  • retention is often poor& good evidence of benefit is hard to find