MOM: Agonist And Antagonist Substitutions Flashcards
Who is medication normally given too?
People with substance addictions, they work to either mimic or block effects of particular substances in the brain. They work at the leve of the synapse
What does Agonist substitutions do?
They enhance cellular activity, and mimic the effects of the addiction
What is the drug used in agonist substatution?
Methadone
What do agonist substitutions do?
It is a chemical that binds to a postsynptic receptor and activates that receptor that receptor to produce a response. As a substitution for drugs, agonists are designed to mimic the action of the drugs such as heroine
When an addiction is maintained, it is often because the individual wants to avoid withdrawal effects, rather than being motivated by pleasurable effects. Therefore agonists such as methadone work by trying to reduce such withdrawal effects
How does methadone mimic the effects of heroin but differ from heroine at the same time?
It occupies the receptors annd mimics the effect of heronin, but without the high, it activates dopamine receptors and releases small amounts of dopamine, but not as much as heroin, this reduces withdrawal symptoms.
One dose will work for 24-36 hours.
How is methadone usually taken? What do the NICE guidelines suggest about dosage?
It is taken orally which means the individual doesn’t experience crashing and rushing as much as they do if they were taking heroin.
NICE suggests that the initial dosage of 10-40mg each day and should be increased by 10mg daily until 60-120mg a day is reached as maintaince dose
What should be offered alongside the medication?
Psychosocial support
What is the process of the dosage being decreased called
Detoxification
What is abstinence?
When a person is able to stop/continue to not take a drug or medication
How long is it recommend for a patient to be on the withdrawal treatment programme?
Minimum of 12 months
How will the methadone be given and who by?
A doctor or nurse will see the patient everyday for the first 3 months whilst administration until they are able to do it without supervision
What is the Antagonist substitution?
Naltrexone
When is Naltrexone used?
During the recovery period
How does it help prevent patients from taking opioids such as heroin?
It occupies dopamine receptors molecules, but doesn’t activate the receptors. This prevents dopamine from attaching to the receptors and activating them. If a patients takes an opioid like heroin they will not experinace a ‘high’ or any pleasure because the dopamine receptors are blocked
What do NICE guidelines suggest about the use o Naltrexone?
That naltrexone should be used by people who have stopped using opioids and have demonstrated that they are highly motivated to stay off drugs.
How long should naltrexone be taken for?
Up to 6 months
What addictions can Naltrexone be used for?
Chemical addictions like heroin and alcohol, but it has also been suggested that it can be used for a gambling addiction, however more research needs to take place
Evaluation: Effectiveness
Supporting evidence for methadone:
NICE: REVEIW
As a part of their guidance on methadone use, NICE asses 31 reviews of its effectiveness. It was found that particpants were more likely to remain on the treatment programme of taking methadone rather than a placebo. This suggests that methadone is effective at retaining particpants which is the first step to methadone being Sucessfull. Particpants reciveing methodone also had lower rates of opioid use to compared to control groups. This suggest that methadone is effective at treating heroin addiction.
Safer Alternative to Methadone: Buprenorphine
Buprenorphine is an alternative to method one, it is a milder medication and has both agonist and antagonist properties. This means it partially activates the dopamine receptors, reducing withdrawal symptoms (like methadone) but it also blocks the receptors, preventing the euphoria assossiated with opioids (like naltrexone)
What is the advantage of using Buprenorphine instead of methodone?
It is safer and has a lower risk of overdose (ceiling effect)
What did Marceau et al 2012 find in relation to the effectiveness of Buprenorphine?
He anylised data over a 5 year period and found that Buprenorphine is 6x safer
Why is methadone the proffered treatment in the UK?
It is more effective in retaining patients as patents preferred the feelings they had with methadone
Opposing evidence for effectiveness of naltrexone:
NICE review
NICE Reveiw 127 studies concerning the effectiveness of naltrexone for heroin addiction. They found conflicting results, with many of the trails not showing any significant difference between naltrextrone and control treatment in relation to retention on the programme
However there were a difference found in relation to relapse rates for those on naltrexone, particularly or those who were highly motivated, closely monitored and offered extra support
Metholodical issues
In order to establish if treatment is effective, research studies are necssary. However with treatment of addictive behvaiours it is much more difficult to conduct valid research. In their reveiws of the effectivenesss of methadone and naltroxone, NICE identified some problems with research in this area
What were the 3 issues NICE identified?
Attrition Rates
Short term studies
Cultural differences
