Opioid Dependence and Treatment Flashcards
What are the types of opiate?
Natural derivatives from plants = morphine, codeine
Semi-synthetics = hydrocodone
Fully synthetic = methadone, tramadol
What system mediates drug induced/natural highs?
The mesolimbic dopamine pathway
What is the ICD-10 criteria for dependence?
3 or more for at least 1 month = sense of compulsion, craving, physiological withdrawl, evidence of tolerance, preoccupation with substance use, persistent use despite harmful consequences
What are some ways to screen for opiate dependence?
Drug diaries and drug screening
Opiate withdrawl scale and risk assessment
Recovery care plan
What is COWS?
Clinical Opiate Withdrawl Scale = rating scale for symptoms of withdrawl (e.g tremor, loose stools), need score of at least 8 to be classed as dependent
What are the physical risks of opiate use?
Skin infection, DVT, blood borne infection, damage to nasal mucosa, damage to respiratory tract
What are the psychiatric risks of opiate use?
Physical dependence, seizures, delirium, paranoia, increased anxiety, depression, psychosis
What are the social risks of opiate use?
Loss of employment, implications for driving, breakdown of relationships, loss of parental rights
What is opiate replacement therapy?
Deliberate prescribing of drugs in a controlled manner
What are the phases of treatment for opiate dependency?
Induction, optimisation, maintenance and reduction
Involve counselling and other agencies throughout
What is methadone?
Mu receptor agonist = controlled drug, given in 1mg/ml liquid preparation
What are some features of methadone?
Long half life = peak plasma concentration at 4 hours, steady state reached in 5 days
Hepatic metabolism via CY3P4
60-100ml doses more effective
High dependence and low lethal dose
What is buprenorphine?
Mu receptor partial agonist with low intrinsic activities and high affinity = sublingual tablets
What are some features of buprenorphine?
Peak plasma levels reached after 1.5-2.5 hours
Duration of effect is dose related = effective dose is range of 12-24mg
What are some side effects of methadone?
Prolongs QT interval and may cause sedation
