Management of opiate misuse Flashcards
What contributes to the addictiveness of heroin?
Rapidity of onset of action
Short half-life
Availability
how many stages to heroin production?
3
Opium
Morphine
Diamorphine
Opium stage?
Mixture of alkaloids (especially codeine and morphine)
Morphine stage?
Morphine is extracted though codeine contaminants often remain
Diamorphine stage?
Addition of 2 acetyl rings to produce diacetylmorphine (diamorphine).
How is heroin taken?
(In order of popularity)
- Intravenous
- Smoking
- Suppository
- Insufflation (blowing into a body cavity)
- Ingestion
Metabolic pathway of morphine?
diacetylmorphine to 6-mono-acetylmorphine to morphine
Effects of heroin (and other opiates)?
euphoria
analgesia
reduced conscious level
constipation
tolerance develops due to repeated use
constricted pupils
If substance, such as heroin, has been injected, there may be evidence of needle mark abscesses or vein collapse at injection sites.
Time frame for withdrawal symptoms for heroin?
typically occurs within 6-8 hours
Withdrawal symptoms of heroin?
Dysphoria and cravings
Diarrhoea, nausea and vomiting
Joint pains
Yawning
Tachycardia and hypotension
Agitation
Anxiety
Dilated pupils
“Goose bump skin”
complications of IV use?
Infections
Local: cellulitis, abscess, thrombophlebitis, necrotising fasciitis
Distant: eg. infective endocarditis,
Systemic: Hep B, HIV, Hep C
Thrombotic/embolic
DVT, PTE, ischaemic limb
other consequences of heroin use?
Social – unemployment, neglect of family/children, alternative interests, criminality, risk of violence, prostitution.
Psychiatric – depression, anxiety.
Heroin use can cause delirium or psychosis. true/false?
false
Does NOT cause psychosis or delirium.
What is opiate substitution therapy?
Replacement of short acting opiate with a long acting opiate
Buprenorphine or methadone
Long acting depot (buvidol)
Once daily dosing and taken under supervision (initially)
Pros of OST?
Reduced mortality rate of less than 1/3 compared to those without therapy.
Reduces HIV infection by ~50%
There is evidence that OST is effective in preventing HCV (hep C) infections
Social benefits to treatment?
Reduces criminality
Promotes pro-social activities
Promotes family life
Promotes employment
Cons of OST?
Daily visits to chemist (initially)
Stigma (methadone > buprenorphine)
Side effects
Ongoing cost but savings elsewhere (Criminal justice, health)
specific drugs used in OST?
Methadone
- long acting full agonist
- Tablet or liquid- but liquid used.
Buprenorphine
- long acting partial agonist
- Tablet or depot
- Different preparations have different dissolution rates (espranor vs sublingual buprenorphine)
partial agonist vs full agonist?
Partial agonist opioids activate the opioid receptors in the brain, but to a much lesser degree than a full agonist. Buprenorphine is an example of a partial agonist.
What determines the long acting opiate treatment for a patient?
The choice of opiate substitute is dependent on patient factors e.g. overdose risk (buprenorphine may have lower risk of overdose).
If both buprenorphine and methadone are suitable. Methadone should be prescribed as first choice. true/false?
True
Stages of opioid replacement?
1) Induction
2) Optimisation
3) Maintenance
4) Reduction
During acute opioid withdrawal, what drugs could help manage the patients symptoms?
Loperamide (for diarrhoea)
Anti-emetics (for nausea)
Benzodiazepines (can be used for agitation)
