Addiction- modification antagonist and agonist substitution Flashcards
How do these work?
Mimic or block the effects of particular substances on the brain
What do agonist drugs do?
Enhances activity
An agonist is a chemical that binds to a postsynaptic receptor and activates that receptor to produce a response. In the case of medication, agonists are designed to imitate the action of another substance such as heroin.
What do antagoist drugs do?
Block receptor sites
What is the agonist substitution?
Methadone
What does methadone agonist do?
Used during an addiction to opioid
When users take heroin it causes an excess of dopamine meaning receptor sites become less sensitive. Thus neurons adapt to high levels of dopamine by releasing less so less pleasurable effect and avoidance of withdrawal
What is methadone?
Replacement for heroin
This occupies the dopamine receptors in the brain mimicking the heroin without the high activating dopamine receptors so reducing the symptoms of withdrawal
-Thus meaning it doesn’t have the same euphoric rush that’s associated with jerion (meaning patients don’t have extreme highs and lows)
-So they will become addicted to methadone and not extremience uncontrolled compulsivity
-Given orally so blood concentration with rise and fall slowly vs crash and rush of injective heroin
What happens after methadone have stabilised withdrawal symptoms?
Patient gradually lowers their dosage via detoxification until they can abstained from it
Why is methadone given orally?
-Given orally so blood concentration with rise and fall slowly vs crash and rush of injective heroin
What is the recommended dosage for methadone/
10-40mg per dosage
Interested by up to 10 mg daily until no signs of withdrawal are seen
What is the antagonist substance?
Naltrexone
Antagonist Naltrexone- what is this?
Used in opioid addictions
Used for addicts in recovery to prevent relapse unlike methadone that manages withdrawal symptoms
Antagonist Naltrexone- what biological action is taken?
Blocks dopamine receptor sites so dopamine can bind
Antagonist Naltrexone- what effect does this have on feelings produced by drugs?
No pleasurable feeling so not rewarding
Antagonist Naltrexone- who is this given to?
People who can relapse
Antagonist Naltrexone- How is this given?
Liquid and tablets
Antagonist Naltrexone- what addictions can it be used for?
Opioid
Meth
Evaluation- effectiveness NICE methadone?
Viewed 31 people for methadone using 27 randomized controlled trials
-Find that people on methadone stayed on study whole way through and had low use of illegal drug use compared to those in placebo that dropped out
Evaluation- effectiveness Van den Brink and Hassans 2006 meta analysis?
Conducted a meta analysis of studied into the effectiveness of a range of treatment conducted that as long as the dosage adequates then methadone is effective as a maintenance treatment
Evaluation effectiveness- what is buprenorphine?
Milder medication that’s both agonist and antagonist that partially activates dopamine receptors reducing the withdrawal symptoms but also blocking receptors preventing euphoria associated with opioids
-Reduced change of overdose due to the ceiling effect, meaning large quantities of drug will not produce greater effect
Buprenorphine Marteau et al study?
Longitudinal study finding buprenorphine is 6x safer than methadone looking at the death
-2366 deaths methadone vs 52 buprephonine
Buprenorphine- Whelan and Remski?
Person with an addiction may prefer the feeling from methadone and are more likely to continue with treatment
Evaluation- effectiveness of naltrexone NICE?
17 studies looking at heroine addicts
Randomised trial showed no significant difference between naltrexone and control treatment on the treatment programme
-When results pooled drug was associated with a reduction in relapse in rats, especially those closely monitored and offering extra support
Evaluation- effectiveness of naltrexone Lahti et al?
Effectiveness of naltrexone on small sample of gamblers, instructed to take it before gambling or when they felt the urge to
Finding it significant decrease in gambling levels although they highlight that further researchers need
Evaluation- Naltrexone Gowing et al?
Not appropriate for all drug users, addicts need to have completely stopped taking heroin due to withdrawal symptoms occurring
-Drug only affective with highly motivated
-Thus meaning high attrition rate so bias sample
Evaluation- ethics side effects of methadone?
Confusion
Dizziness
Changes in heartbeat
Tremors
Seizures
Anxiety
Evaluation- ethics dangers of methadone?
Can interact with other drugs like alcohol and antidepressant to cause respiratory problems
Dangers of overdose
2023- deaths 209
Evaluation- risks of naltrexone?
Unethical as it can create another addiction
Monitoring liver issues
If person is still opioid dependant taking this may cause withdrawal symptoms and displace opioids still in receptors
Evaluation- ethics counter argument?
Do side effects outweigh addiction?
Evaluation- social implication?
Economy= can addicts be in work, cant contribute to economy
Healthcare- strain on NHS, funding methadone when we aren’t 100 sure its effective
Society- reducing addiction, better society, more people in work and better economy
Evaluation- social implication the national treatment agency?
Treating heroin users with methadone is positive as it reduces criminality suggesting rates of offending are reduced by half when addicts are in treatment
Evaluation- social implication Gyungell?
Drug related reoffending has continued to rise despite the availability of drug treatment like methadone, possible problem is that by availability of drug treatment like methadone
Possible problems is that by settings up methadone program centered on particular place and people concerned about possible increase in crime and antisocial behaviour in neighbourhood
Evaluation- social implication what did the the advisory council for the misuse of drugs and the environment?
People who are disadvantaged are more likely to overdose as they dont have the sufficient recourses to get help for overdose
Evaluation- cost effectiveness Gyungell?
Prescribing methadone was an expensive failure and cost society’s money, not only for methadone but the 320,000 problem drug users benefit greater success would be achieved by funding rehab until encourages justice
Evaluation- cost effective Doward?
Charity drug scope has distribution the claims made in the report, says it overstimulate the cost of prescribing methadone
