Substance misuse (spring) Flashcards
What is substance abuse?
A disorder characterised by the destructive pattern of using a substance which leads to problems or distress
why abuse drugs?
as a normal physiological function, engaging in (positive) rewarding behaviours lead to pleasurable feelings
drugs represent substitutes for such behaviours
positive feedback can lead to psychological and physiological addiction
define…
Addiction:
Reinforcing stimuli:
Rewarding stimuli:
Addictive drug:
Addictive behaviour:
Sensitisation:
Addiction: a state characterized by compulsive engagement in rewarding stimuli despite adverse consequences
Reinforcing stimuli: stimuli that increase the probability of repeating behaviours paired with them
Rewarding stimuli: stimuli that the brain interprets as intrinsically positive or as something to be approached
Addictive drug: a drug that is both rewarding and reinforcing
Addictive behaviour: a behaviour that is both rewarding and reinforcing
Sensitisation: an amplified response to a stimulus resulting from repeated exposure to it
define…
Tolerance:
Dependence:
Physical dependence:
Psychological dependence:
Tolerance: the diminishing effect of a drug resulting from repeated administration at a given dose
Dependence: an adaptive state associated with a withdrawal syndrome upon cessation of repeated exposure to a stimulus (e.g., drug intake)
Physical dependence: dependence that involves persistent physical–somatic withdrawal symptoms (e.g., fatigue and delirium tremens)
Psychological dependence: dependence that involves emotional–motivational withdrawal symptoms (e.g., dysphoria and anhedonia)
Factors affecting likelihood of drug abuse
Abuse: Sexual, psychological, emotional or physical abuse can influence drug use as a coping mechanism
Underlying emotional disorders: Individuals with anxiety, depression, bipolar disorder or post-traumatic stress disorder are at increased risk of substance abuse and addictive behaviours.
Family history: Children raised by alcoholic or drug-addicted parents are more likely to develop substance use problems.
Inherited factors: Genetic susceptibilities and biological traits play a role in addiction and abuse but development is shaped by a person’s environment
Low frustration tolerance: Addicts are highly susceptible to the negative effects of stress
The substance: Some substances are more addictive than others.
factors leading to addiction?
what are some categories of Abused substances?
- Alcohol
- Nicotine: E.g. cigarettes, e-cigarettes
- Euphorics: E.g. cannabis, ketamine, nitrous oxide, salvia
- Opiates E.g. heroin, morphine, codeine
- Benzodiazepines: E.g. diazepam
- Stimulants: E.g. cocaine, amphetamine, ethylphenidate
list anatomical and physiological biological systems that are involved in effects
Anatomical:
- Meso-cortico-limbic system
- Hypothalamus
Physiological:
- Acetylcholine: piracetam
- Adenosine: caffeine
- Dopamine: cocaine, phenidates, amphetamines
- GABA: benzodiazepines
- Norepinephrine: yohimbine
- AMPAR: piracetam
- CB1R: tetrahydrocannabinol (in cannabis), cannabinomimetic NPS
- NMDAR: ketamine
- Opioid receptors: buprenorphine, heroin
- Orexin receptor: modafinil
name and briefly describe Behavioural treatment
approaches
Cognitive-behavioural therapy: Based on behaviours being learned responses which, through learning different responses, can be altered.
Contingency Management Interventions: Rewards compliance with abstinence
Motivational Enhancement Therapy: Focusses on identifying the need to change behaviours
Family Behaviour Therapy: Therapy undertaken with at least one significant other at session
Principles of pharmacological therapies for substance misuse:
Abstinence: included as can include use of pharmacological treatments which deter misuse e.g. Disulfiram for alcohol abuse, naltrexone after detoxification is complete)
Detoxification: Pharmacological induction of withdrawal e.g. naltrexone to block opioid receptors plus lofexidine (a2A adrenoceptor agonist) to reduce withdrawal symptoms)
Replacement/substitution therapy: Replacement of abused substance with, typically, a longer acting but less euphoric substitute (e.g. buprenorphine to replace heroin). Encourages stability and routine
Formulation or distribution to reduce misuse potential of replacement therapies: E.g. sublingual buprenorphine and naloxone has poor naloxone (antagonist) bioavailability but, if injected, blocks effects of buprenorphine (and other opiates)
The role of the pharmacist in substance misuse
substance misuse services
- Primarily pharmacological therapies
- Reporting missed doses
- Needle exchange schemes
- Health promotion and harm reduction
Identifying interactions
Detecting misuse:
- Unusual patterns of OTC medicine purchase (e.g. of codeine-containing medicines)
- Altered prescriptions (quantity, strength)
- Diversion of medicines
give examples of Phytocannabinoids
Δ9-tetrahydrocannabinol
Cannabidiol
Cannabigeroland
describe the structure of Δ9-tetrahydrocannabinol (‘THC’)
phenol ring, 5-carbon alkyl chain, central pyranring and mono-unsaturated cyclohexylring
clinical uses of synthetic cannabinoids
pain management
anti-emetic
appetite stimulant
anti-spastic
what consequences do drug abusers experience?
most common abused forms of cannabis?
Dried flowering tops of the female plant (‘buds’)
- Leaves have little cannabinoid content and so are rarely used
Resins and oils
- traditionally made from compression of the dried trichomes(‘slate’, ‘black’ etc.)
- Now often made by butane-based extraction (‘bubble’)
Some advocates of juicing the fresh plant
- Non-psychoactive as cannabinoids are present in the acid form and decarboxylated by drying and/or heating
Routes of administration of unlicensed cannabis?
uses of licensed cannabis?
Long term toxic effects of cannabis?
- Addiction
- Altered brain development
- Poor educational outcome, with increased likelihood of dropping out of school
- Cognitive impairment, with lower IQ among those who were frequent users during adolescence
- Diminished life satisfaction and achievement (determined on the basis of subjective and objective measures as compared with such ratings in the general population)
- Symptoms of chronic bronchitis
- Increased risk of chronic psychosis disorders (including schizophrenia) in persons with a predisposition to such disorders
Clinical management of cannabis abuse?
withdrawal symptoms of cannabis?
withdrawal symptoms not serious:
Dysphoria, disturbed sleep, decreased appetite
Salvia divinorum…
family?
moa?
use?
Family: Lamiaceae. Mint, salvia, oregano, marjoram, lavender, thyme
Hallucinogenic (leaves)
Native of Mexican Sierra and used by Mazatecs for ritual purposes
Salvinorin A…
moa?
dose?
effects?
what are the effects of Salvinorin A at different doses?
low doses ameliorate pain and mood
high doses exacerbate these symptoms
Nitrous oxide moa?
uses of nitrous oxide?
why is the abuse of nitrous oxide increasing?
Effects of gas inhalation?
is it short or long acting?
Clinically used as an analgesic during dental surgery and childbirth
Abuse increasing due to widespread availability and current legality
Effects of gas inhalation:
- Dizziness
- Euphoria
- Bursts of laughing
- Dissociation
- Sexual performance enhancer
Short acting (minutes; dependent on dose)
what happens when High levels of nitrous oxide are inhaled?
(give the mechanism, physical symptoms and therapy)
Mechanism
- N2O makes VitB12 unavailable
- Homocysteine accumulates leading to over stimulation of NMDARs, hyper-acidification and apoptosis
Physical symptoms
- Nerve damage, demyelination and neuropathy
- Vomiting and nausea
Therapy: high doses of Vit B12
What is the aim of drug misuse services?
To reduce the harms and costs arising from alcohol, prescribed and non-prescribed drug use and other substances.
To ensure that all aspects of a service user’s life are considered holistically, including substance misuse, housing, education, training, employment, offending, healthcare, family life, relationships, community participation and support networks, religion and culture.
To enable service users to take personal responsibility for their own self care and recovery, their families, children and the community.
PERSON CENTRED CARE
Who manages the treatment of patients?
Local management, organisation and payment for services via Public Health England (commissioned by Local Councils)
Services provided by specialist charities and NHS mental health units
e.g. Turning Point, Addaction, KCA, WDP, Reach Out Recovery, Alcohol and Drug Abstinence Service,Iris
How do people get referred to services?
- Self referral
- Police
- Social workers
- GP and other HCPs including pharmacists
- Criminal justice service
what is involved in the Management of Drug Misuse (from the start)?
Initial review: interviews and testing for substance misuse-urine (e.g. Eco cups) and blood testing, use of Clinical Opiate Withdrawal Scale (COWS)
Psychosocial and Pharmacological interventions- provided in the community and criminal justice system: include inpatient, residential, day-patient and outpatient services.
Psychosocial treatment
- Cognitive behavioural/psychodynamic therapy
- Behavioural couples therapy
- Contingency management-key worker
- Treat comorbid depression and anxiety
Pharmacological treatment-opioids/benzodiazepines
- Detoxification
- Abstinence
- Maintenance (substitution/ harm reduction) therapy
Management of Opioid Misusers… what happens during detoxification?
methadone or buprenorphine substitution then withdrawal if previously in maintenance therapy or as a patient choice
lofexidine (Britloflex®200mcg tablets) alone for young people, mild or uncertain dependence, short history of illicit drug use, rapid detoxification. (for Management of symptoms of opioid withdrawal)
what class is lofexidine?
what does it do?
dose?
what time of day is it given?
side effects?
monitoring requirements?
alpha2-adrenergic agonist
alleviates physical symptoms of withdrawal (not reduce craving).
Can also be used with opioid substitute (methadone or buprenorphine)
800mcg daily increased up to max 2.4mg daily (divided doses). 7-10 days use for sole therapy
Give at bedtime to offset insomnia.
Side effects-dry mucous membranes, hypotension, bradycardia, dizziness, drowsiness, QT interval prolongation-caution for interacting drugs
Monitor BP, pulse at initiation and for first 72 hrs or until stable dose and also on gradual discontinuation over 2-4 days.
which drugs are used to manage different withdrawal symptoms?
loperamide - diarrhoea
mebeverine - stomach/intestinal cramps
paracetamol and NSAIDs - muscular pain and headaches
metoclopramide/prochlorperazine - vomiting
short-acting benzodiazepines or zopiclone - insomnia, anxiety
Muscular pain-sometimes use topical therapy-voltarol gel
(Benzodiazepines are used for a few days only as addictive in themselves.)
Management of Opioid Misuse… what happens during abstinence
Detoxification programme followed by relapse prevention support
Abstinence supported for at least 6 months with psychosocial and drug therapy (mildly dependent clients may only need drug therapy)
Naltrexone is support for opioid abstinence. Naltrexone (Nalorex®) competitively displaces opioid agonists, blocking euphoric effects and minimising positive rewards associated with opioid use.
- Licensed as an adjunctive prophylactic treatment for detoxified formerly opioid-dependent people who have remained opioid free for at least 7–10 days.
- Test for opioid use with naloxone prior to starting naltrexone
- 25 mg naltrexone on day 1 followed by 50 mg daily thereafter for an initial period of 3 months or 3 x a week dosing
Management of Opioid Misuse…
what is the aim of Maintenance (substitution/ harm reduction) therapy?
which drugs?
Aims to provide stability by reducing craving and preventing withdrawal, eliminating the hazards of injecting and freeing the person from preoccupation with obtaining illicit opioids, and to enhance overall function.
Methadone, buprenorphine or Suboxone®
Drugs are given as part of a programme of supportive care
Prescribing of diamorphine (also dipipanone and cocaine) to treat addiction only allowed if prescriber has a Home Office license
Role of Pharmacies in Maintenance Therapy
- Significant point of contact with the client
- Provide information and advice
- Monitor for ADRs, interactions
- Monitor for other health issues (mental health, onset of problems relating to drug misuse or unrelated health issues)
- Encourage participation in harm reduction strategies
- Refer back to drug misuse team or prescriber where necessary
- Service Specification from local council (PHE) describing contracted duties
Maintenance Therapy for Methadone… dose?
- Initially 10-40mg daily
- Increase by up to 10mg daily (max 30mg weekly titration) until no signs of withdrawal or intoxication
- Usual dosage range 60-120mg daily
- Usually single dose-large doses may be twice daily e.g. 80mg supervised, 40mg to take home.
- Long t½ (15-60 hours) so no ‘rush’ and withdrawal onset 1-3 days, peak 3-6 days unlike heroin (t½ 2-3 minutes, withdrawal onset 6-12 hours, peak at 36-72 hours)
what are the different dosage forms of methadone?
1mg/1ml oral solution sugar free (SF) and non SF (green liquid)
10mg/1ml oral liquid for dilution with diluent (Methadose)(blue)
Tablets 5mg (Physeptone) (unlicensed)
Injection:
- 10mg/ml 1ml amps
- 10mg/ml 2ml amps
- 50mg/2ml amps
- 50mg/1ml amps
side effects of methadone?
- Nausea and vomiting
- Urticaria, pruritis, rashes
- Vertigo
- Sweating
- Bradycardia or tachycardia
- Mood changes
- Constipation
- Drowsiness/dizziness
using which route of administration is nausea worse in, with methadone?
Nausea worse with oral than injected
can you drive whilst under the influence of methadone?
It is an offence to drive while under the influence of this medicine but patients would not be committing an offence if:
- The medicine has been prescribed to treat a medical problem and
- It was taken according to the instructions given by the prescriber and in the information provided with the medicine and
- It is not affecting the ability to drive safely
Maintenance Therapy with Buprenorphine…
dose?
moa?
- Initially 0.8-6mg daily
- Increased at intervals until no signs of withdrawal or intoxication
- Usual dosage range 8-24mg daily, maximum 32mg daily
- Once daily dosage. Placed under the tongue and allowed to dissolve-sometimes need glass of water before to get mouth moist enough to dissolve.
- t½ 12 hours, duration 12-72 hours.
- Partial opioid agonist
- Blocks effects of ‘top up’ heroin
what are the different dosage forms of Buprenorphine?
Sublingual tablets (Subutex and generic, 0.4, 2 and 8mg strengths)
Temgesic S/L tabs unlicensed for substance misuse (0.2 and 0.4mg)
Suboxone® is SL buprenorphine with naloxone (opioid antagonist to reduce iv misuse-precipitates withdrawal if injected but ineffective orally or SL) 8/2mg and 2/0.5mg strengths
Espranor oral lyophilisate (freeze-dried wafer that dissolves rapidly on the tongue)
2 and 8mg strengths-not interchangeable with S/L formulation