Substance Misuse Flashcards
Define drug
Any natural synthetic or natural chemical substance that is used in the treatment, prevention or diagnosis of disease.
Why do people take drugs?
- For pleasure, to get a ‘rush’, euphoria –> positive reinforcement/ reward
- As anxiolytics or to overcome withdrawal –> negative reinforcement
- Because people are addicted and cannot control their use –> overwhelming urge
The ____ the onset of the drug effects, the better the ______
faster
rush
Finish the chain, from slow to fast:
- Chewing tobacco, _____, ____
- _____ _____, paste, _______, ____
- ________, _________, snorted, __ ________
- snuff, cigarettes
- cocoa leaves, cocaine, crack
- methadone, morphine, IV heroin
Explain the science of addiction.
- Drugs of abuse increase DA in the nucleus accumbens of the mesolimbus
- Increase in DA is key to +ve reinforcement
- DA increased by cocaine, amphetamines, alcohol, opiates, nicotine and cannabinoids.
The nucleus accumbens has high levels of ____ receptors
D3
The nucleus accumbens:
- high levels of D3 receptors
- DA release here is involved in learning associations
- Reduced DA is noted in withdrawal states and is likely to be associated with depression, irritability and dysphoria.
- DA is modulated mu opioids
Opiates are ______ substances ; e.g. ______, ______
Opioids are ____- _______; e.g __________, _______
or ______; e.g. ______
natural
morphine, codeine
semi synthetic
dihydrocodeine,heroin
synthetic
methadone
What receptors do opioids act as agonists at?
delta
kappa
mu
nociceptin receptors
What effects are seen when opioids bind to delta receptors?
antidepressant, physical dependence, analgesia
What effects are seen when opioids bind to kappa receptors?
sedation, dysphoria, miosis, inhibition of ADH release
What effects are seen when opioids bind to mu receptors?
analgesia, euphoria, +ve reinforcement, respiratory depression
What effects are seen when opioids bind to nociceptin receptors?
anxiety, depression, appetite, tolerance to mu agonist
What are some chronic effects of opioids?
depression, insomnia, constipation, dependence, ahedonia
What are some acute affects of opioids?
itching, miosis, nausea, euphoria, drowsiness, tranquility
Mechanism of tolerance is?
not well understood
How are opioids taken?
smoked, swallowed, injected, inhaled
Opioid withdrawal:
- may occur within hours of the last ‘fix’
- may peak between 2 - 4 days
- usually will not last beyond 7 days
THE ONSET, INTENSITY AND DURATION IS MULTIFACTORIAL. (e.g. previous experiences of withdrawal may be an important variable)
What are some symptoms of withdrawal?
Depression Diarrhoea Shivering Restlessness Insomnia Dilated eyes Myalgia Tachycardia Piloerection Rhinorrhoea
Opioid withdrawal is associated with
increased noradrenergic activity due to opioid affect on locus coeruleus… tachycardia, piloerection
short term opioid detoxification takes
30 days
long term opioid detoxification takes
180 days
what are some pharmacological aids for opioid detoxification?
In order to suppress all aspects of withdrawal:
methadone - full mu agonist
buprenorphine - partial mu agonist
In order to suppress autonomic signs - not subjective discomfort
clonidine - a2 adrenoceptor agonist
rapid opioid detoxification takes
3-10 days
ultra rapid opioid detoxification takes
1-2days
ultra rapid opioid detoxification:
withdrawal is precipitated using?
naloxone naltrexone PLUS: - clonidine benzodiazepine general anaesthesia
What’s the risk of rapid/ ultra rapid opioid detoxification
respiratory distress, renal complications
How does methadone work?
Attenuates withdrawal + craving but patient does not experience ‘rush’
Why is methadone administration supervised?
to reduce risk of abuse (there is some evidence of a black market for methadone - addicts sell methadone to finance buying heroin)
Maintenance therapy of methadone.
Talk about it’s half life
It can be v. effective but there is risk of dependence.
It has a long half life. One oral dose of methadone can suppress craving for heroin + withdrawal symptoms for 36 hours.
Acute action of opioid is to _____ cAMP and _______ NA neuronal firing.
inhibit
reduce
Chronic action of opioid is ________ __-_____ of cAMP. This results in an _______ in NA tone which is revealed on _________ symptoms
compensatory
up-regulation
increase
withdrawal
Compare methadone and buprenorphine for maintenance/ detoxification
Methadone:
- full mu opioid agonist
- half life: 24hrs but on chronic dosing; 36hrs.
Buprenorphine
- partial mu opioid agonist therefore reduced risk of respiratory depression
- Antagonist at kappa therefore less likely to cause dysphoria
- half life: 24hrs therefore withdrawal syndrome less
If heroin is injected, buprenorphine is useful because it’s ______ property will prevent relapse
antagonist
What is naltrexone?
- oral
- non-selective opioid antagonist (blocks acute opioid effects)
- used to prevent relapse in drug-free subjects
- most common adr’s are GI
Most common ADR for Naltrexone is?
GI disturbance
What are some acute affects of cocaine?
formication euphoria increase heart rate and bp confusion psychosis
What are some chronic affects of cocaine?
paranoia depression psychosis anorexia variable effects on D1 and D2 receptors
What happens when cocaine use stops?
‘CRASH’
- depression
- anxiety
- hypersomnia (sleepy throughout the day)
- anergia (abnormal lack of energy)
What is the current therapy for cocaine use?
Partial D3 agonist
THC alters both ______ and ________ neuronal activity
hippocampal
cerebral
Acute effects of THC?
relaxation confusion distorted perceptions anxiety impaired memory, concentration and coordination
The most commonly abuse drug in the UK is?
alcohol
Alcohol misuse results in
Psychological Physiological Psychiatric and Societal damage
Alcohol misuse is when:
a patient drinks to the extent of causing harm to self or others
EQUATION FOR ALCOHOL UNITS
Alcohol by Volume (%) x Litres = units
IF <50 units/week;
May not be required
IF 50-100 units/week;
Consider detox
IF >100 units/week
Detox required
What are some risk factors that have an increased need for alcohol detox
- older patients
- severe dependence
- Hx of failed community detox
- Psychiatric co-morbidities - Poor physical health e.g. Diabetes, Liver damage, HTN
- Hx of DTs and alcohol withdrawal seizures
- Poor social support
- Cognitic impariment
What are some pharmacological agents for alcohol detox
- Benzodiazepines e.g. Diazepam
- Thiamine; High Potency Parenteral; Pabrinex IV / IM; 1 pair ampoules daily for
3-5 days. - Then; long-term Vit B Co.Strong; One Tab PO; OD.
ALSO BREAKTHROUGH DOSE OF:
Diazepam 10mg PO Max TDS should be prescribed for ‘breakthrough’ withdrawal symptoms, WHEN REQUIRED
ALSO, FOR SEIZURES:
Diazepam 5 – 10mg PR; PRN for seizures should also be prescribed. WHEN REQUIRED
Alcohol:
Pharmacological ‘Tools’ to support continued abstinence include:
- Disulfiram ~ Antabuse
- Acamprosate
- Naltrexone
- Nalmefene
MOA of Disulfiram
Irreversibly inhibits effects of ALDH. SO, acetaldehyde accumulates. Leads to:
- N&V
- Headache
- Sweating
- Palpitations/ Tachycardia
- Flushing
Large doses of alcohol + disulfiram =
- hypotension
- collapse
- arrhythmias
Adverse effects of Disulfiram?
- N & V
- Halitosis
- Psychiatric reactions; paranoia , depression
- Hepatic cell damage
