Substance Abuse Flashcards
what is the dose of paracetamol ingested which is potentially fatal?
> 12 g in totoal
> 250mg/kg = likely
<150 mg/kg = unlikely
pathophysiology of paracetamol overdose
• mainly inactivated by liver by conjugation leading to 2 metabolites glucuronide or sulfate
o overdose, liver is overwhelmed metabolised in alternative pathway (p-450)
o result in toxic metabolite N-acetyl-p-benzoquinone imine (NAPQI)
o NAPQI inactivated by glutathione harm prevented
o glutathione runs out NAPQI reacts with hepatocytes and cause necrosis
how does N-acetycycsteine prevent harm of paracetamol?
replenishes glutathione stores
what are some of the RF for paracetamol overdose worsening
alcoholics
pt on p450 inducers eg anticonvulsants, rifampicin, St jon’s wart
clinical featres of paracetamol overdose
- N+V
- abdo discomfort at first
- pain and tenderness over liver (after 12 hours)
- jaundice (2-4 days)
- coma due to hypoglycaemia (after 1-3 days)
- hepatic encephalopathy (3-5 yrs)
- loin pain, haematuria and proteinuria initial renal failure
- bleeding coagulant abnor due to liver damage
- hyperventilation due to metabolic acidosis
- cerebral oedema, septicaemia and DIC causes fatality
- can be asymptomatic initially and if not severe enough
investigation for paracetamol overdose
• Paracetamol level level taken after 4 hours of ingestion
o or asap if staggered dose
• U&Es, creatinine AKI
• LFT if ALT > 1000 IU/L hepatotoxicity
• Clotting prothrombin time = best indicator of severity of liver failure
• Glucose hypoglycaemia risk
• FBC for platelets
• body weight needed for treatment calculation
management of paracetamol overdose
- Acute poisoning STAT dose of activated charcoal if within 4 hours of ingestion to dec absorption
- IV Parvolex (NAC) if on or above the of timed plasma paracetamol level –> 1st infusion (losing dose of 160mg/kg body weight over 1 hour), then 50 mg/kg over the next 4 hours, then 100 mg/kg over the next 16 hours
- Methionine can be used if refused IV Parvolex
- Liver transplantation occasionally needed for hepatic failure
Risk factors for getting opiate overdose
mental health conditions, financial problems, and crime
in a relationship that is protective
opiate dependence
alcohol –> enhance the sedative effect of opiate
hepatic impairment
renal impairment
- hypotension
- hypothyroidism
- Asthma
- prostatic hypertrophy
what is the most common cause of opiate overdose?
accidental overdose
intentional overdose
clinical features of opiate overdose
• if chronic problem constipation, N+V, loss of appetite, dependence
• Acute toxicity
o N+V
o Respiratory depression +/- cyanosis/coma/apnoea,
o hypotension
o tachycardia
o pinpoint pupils (miosis)
o non-cardiogenic pulmonary oedema (from heroin/other opioids)
investigation for opiate overdose
- urine drug screen (only detect presence but not quantity)
- baseline bloods FBC, U&Es, LFT, TFT, creatine kinase, ABG
- CXR if pulmonary oedema suspected
- AXR
- ECG arrythmias is possible from opiate toxicity
management of opiate overdose
• A-E assessment
o A – clear airway especially if resp depression
o B – ventilate on O2 if breathing inadequate due to resp depression
o C – IV access + bloods + ECG
IV naloxone (if no Iv access then IM) (0.4-2mg for adult, 0.01mg/kg for children)
• small dose then inc doses every 2-3 minutes if no response
o 0.04 mg
o 0.5 mg
o 2 mg
o 4 mg
o 10 mg
o 15 mg
• observe carefully for recurrence of CNS and resp depression
activated charcoal if ingested within 2 hours
Naltrexone for those who want to stay clean
what is Salicylate
aspirin - a derivative of salicylate which are present in high conc of oils and wintergreen
pathophysiology of salicylate overdose
• characterised by acid-base disturbances, electrolyte abnor and central nervous system effects
what are the doses of aspirin ingested will the person need admission
- ingested > 250 mg/kg aspirin = moderate toxicity
- > 500 mg/kg aspirin = severe and possibly fatal toxicity
ingested < 125 mg/kg aspirin & no symptoms do not require hospital admission
what are some of the risk factors for salicylate overdose
children and elderly late presentation pulmonary oedema, CNS features, hyperpyrexia metabolic acidosis salicylate conc above 700 mg/L
clinical features of mild salicylate overdose
N+V, tinnitus, lethargy or dizziness
clinical features of severe salicylate overdose
dehydration, restlessness, sweating, warm extremities with bounding pulses, inc RR, hyperventilation and deafness
uncommon features of salicylate overdose
hypokalaemia, haematemesis, hyponatraemia/hypernatremia, abnor blood coagulation (inc prothrombin ratio/INR) etc
• CNS confusion, disorientation, coma and convulsions
features of chronic salicylate overdose
anxiety, tachypnoea, diffuse sweating, difficulty concentrating, confusion, hallucinations and agitated delirium
what are the investigations for salicylate overdose?
1) plasam salicyate concentrations - severity of salicylate level at 2- 4 hours after ingestion & repeat another at 2 hours after the first level
2) bloods - FBC, U&Es, LFT, clotting, urinary pH (monitoring), blood glucose, ABG (risk of metabolic acidosis)
3) ECG - widen QRS, AV block, ventricular arrhythmia
what are the different acid-base staging of salicylate overdose
1) stage 1 - blood pH > 7.4, urine > 6 (respiratory alkalosis –> inc urinary excretion of bicarbonate)
2) stgae 2- blood pH > 7.4, urin pH < 6 - metabolic acidosis with compensating resp alkalosis, urinary hydrogen exrection, intrac-cellular potassium depletion
3) Stage 3 - blood pH < 7.4, urin pH < 6 - severe metabolic acidosis and hypokalameia
what is the management of salicylate overdose
if ingested within 1 hour - activated charcoal
aggressive rehydration
correct acid-base and electrolyte abnor
glucose infusion if hypoglycemia
vit K if hypoporthrombinaemia
urinary alkalization (IV sodium bicarbonate to inc poison elimination) - optimum urinary pH is 7.5 - 8.5
moderate to severe - hemodialysis
what are some of the complications for salicylate overdose
ARDS cardiac arrest seizures hepatitis Reye's syndrome (liver and brian damage in children < 20) renal failure DIC
definition of alcohol abuse
over a 12-this month period - Patients drinking has cause clinically significant impairment or distress (determined by the presence of at least 2 or more diagnostic criteria)
what are the 11 DSM V features of alcohol abuse
1) Alcohol is often taken in large amounts or over a longer period than was intended
2) persistent desire or unsuccessful efforts to cut down or control alcohol uses
3) great deal of time spent in activity necessary to obtain alcohol, use alcohol, to recover from its effects
4) craving or a strong desire or urge to use alcohol
5) recurrence alcohol use resulting in failure to fulfil major role obligation at work, school or home
6) continued alcohol use despite having persistent or recurrent social or interpersonal problems causing or exacerbated by the effect of alcohol
7) Important social, occupational, or recreational activities are given up or reduced because of alcohol use
8) recurrent alcohol use in situation in which is physically hazardous
9) alcohol use is continued despite knowledge of having a persistent or recurrent physical or psychological problem that is likely to have caused or exacerbated by alcohol
10) tolerance
a. a need for marked Lee increased amounts of alcohol to achieve intoxication or desire effect
b. a markedly diminished effect with continued use of the same amount of alcohol
11) withdrawal
investigations required for alcohol abuse
CAGE
AUDIT screening (Alcohol use disorder investigation test - the severity of alcohol misuse
LFT - inc GGT, AST> ALT
management of alcohol
o Initial structured brief advice [FRAMES model]
o Extended brief intervention – up to 5 sessions of motivational interviews, undertaken by a those with relevant training
o CBT/behavioural therapy
o Referral to a specialist alcohol treatment service - Can be given chlordiazepoxide (benzo) or sometimes diazepam
o Risk of malnourishment – oral thiamine
o Wernicke encephalopathy – IV thiamine
Feedback about the personal risk of impairment
Responsibility - personal responsibility
Advise to cut down
Menus of alternative drinking pattern
Empathic consultations
self-efficacy - an interview-style which improves the patient’s self-efficacy
what are some of the complications of alcohol abuses
alcoholic liver disease, cirrhosis, pancreatitis
Wernicke’s encepathalopathy
chronic thiamine deficiency - Korsakoff syndrome (dementia)
prevention of alcohol abuse?
- prevent relapse with local core services, psychiatry and alcohol nurse specialists
- frequent counselling and follow up AA 12 steps CBT programme
• medications
o Acamprosate (GABA analogue) – stops the effect of alcohol
o Naltrexone - opioid receptor antagonist that can modify the effect of alcohol by blunting its pleasurable effect and reducing cravings
o Disulfiram - causes unpleasant symptoms i.e. flushing, palpitations, nausea, and headache
what is the definition of binge drinking
as classified by The National Institute on Alcohol Abuse and Alcoholism (NIAAA) = drinking pattern that leads to a blood alcohol concentration (BAC) level of 0.08 g/dL and above
• For adult women, that’s typically around 4 drinks (5 for adult men) within a couple of hours of each other.
clinical features of alcohol intoxication
- Vomiting
- Anterograde amnesia
- Sleep impairment
- Dysarthria
- Delayed reaction time
- Euphoria
- Decreased inhibitions
- Emotional instability
- Ataxia
- Nystagmus
- Hypoglycaemia
- Drowsiness
- Confusion
clinical features of alcohol poisoning
- Confusion
- N+V
- Slowed/irregular breathing
- Cyanosis
- Pale skin
- Hypotension
- Hypothermia
- Unconsciousness
- Seizures
stages of alcohol intoxication
subclinical euphoric excitment confusion stupor coma death
investigation of alcohol intoxication
blood-alcohol level
management of alcohol intoxication
Behavioural techniques +/- medication like alcohol abuse
behaviroual technique to avoid getting into a fight with an alcohol-intoxicated person
clinical features of simple alcohol withdrawal
• simple - start within first 12 hours of stopping/ reducing alcohol intake o anxiety o restlessness o Tremor o Insomnia o N+V o sweating o tachycardia o ataxia
clinical features of complicated alcohol withdrawal
• complicated – A history of
o Withdrawal seizures – self-limiting grand Mal (tonic chronic)seizure occurring hours to days after last drinks
o delirium tremens uncommon significant mortality starts >48 hours after stopping combined simple withdrawal with • autonomic hyperactivity (Tachycardia , hyper-reflexia, hypertension, fever, visual or tactile hallucination, sinister delusions, disorientation and confusion)
o Alcoholic ketoacidosis after stopping drinking, vomit profusely and do not eat
present with vomiting, signs of chronic alcohol use, high anion gap metabolic acidosis
ix for alcohol withdrawal
• ↑ HR, BP and temp
- ABG:
- ↓ pCO2, ↓HCO3-, normal pO2.
- pH variable as metabolic acidosis may be altered by metabolic alkalosis from vomiting and possible respiratory alkalosis (due to hyperventilation)
• CIWA (Clinical Institute Withdrawal Assessment for Alcohol) – quantify the severity of alcohol withdrawal
mx for alcohol withdrawal
Simple
• Managed as an outpatient or day patient
• May commence treatment for uncomplicated withdrawal but should not prescribe long term
o Diazepam 5-10mg PO or Chlordiazepoxide 10-30mg + thiamine
Complicated
• Withdrawal seizures – Check BM and treat as epileptic fits. Examine for head injury.
• DTs – Monitor closely, check BM, give IV lorazepam as appropriate and refer to medics.
• Alcoholic ketoacidosis – Give IV 0.9% saline with 5% glucose and thiamine supplementation (Pabrinex), whilst monitoring U&E, glucose. Refer to medics and consider HDU/ICU
Admitted:
• Nurse in a well lit room to prevent disorientation
• Monitor BM
• Rehydrate – if IV required avoid saline if known chronic liver disease + monitor urine output
• IV or oral thiamine for 1 week
• Chlordiazepoxide or diazepam for agitation
• Watch out for severe hypophosphatemia – treat with IV phosphate
• Arrange follow up to alcohol dependence clinic
how do you assess level of dependence of cigarette
questions
1) how many cigarettes do you smoke a day
2) how soon after waking do you smoke your 1st cigarette
3) any previous attempt - how successful
4) did you try any treatment
5) did you have any support eg the stop smoking service
6) did you have any withdrawal symptoms or craving?
investigation for somoking
Carbon monoxide level
management of smoking (non-medical)
• very brief advice
o Current impasse smoking history
o verbal and written information on risks of smoking and the benefits of stopping smoking
o Advise on options for quitting smoking including behaviour supports, medication and E-cigarettes
o Refer to local stop smoking services if they wish to stop smoking
- Set a quit day and stick to it abrupt cessation is the best way to quit
- advised that the first few days of the most difficult (withdraw symptoms) the best way to quit is with behaviour support her medication
• craving are often set off by
o stress - breathing techniques
o seeing others smoke
o becoming intoxicated - try not to drink alcohol in the first week
• manage craving /keep distracted o short bouts of moderate exercise o talk to family member or friend o keep busy playing a game on your phone o go to another environment
• supporting quitting
o information on smoke free national helpline
o support from family and friends
o quit with someone else
management of smoking - medical management
nicotine replacement therapy (short and long acting forms being used together = best) - patch (16/24 hrs) + short acting eg inhaled
varenicline - best used alone, start 7-14 days before quit date
Bupropion - least effective out of all 3 start 7-14 days before quit date
what are the side effect of vareicline
agitation, depressed mood, suicidal thought (stop), N+V, constipation/diarrhoea, dry mouth, insomnia
what are the side effect of bupropion
agitation, depressed mood, suicidal thoughts = stop
what meds do you use for opioid detoxification?
methadone/buprenorphine
what meds do you use for amphetamine detoxification?
activated charcoal if ingested recently
benzodiazepines (Diazepam)
dexamphetamine (used to treat dependence)
what meds do you use for alcohol detoxification?
chlordiazepoxide (to help with withdrawal)
Carbamazepine/clomethiazole (acute withdrawal)
what meds do you use for Benzodiazepine detoxification?
longer acting benzodiazepine (Diazepam)
what is solvent abuse
- deliberate inhalation of a volatile substance to achieve and altered mental state
- detoxification not necessary as no withdrawal symptoms have been identified (bar gammahydroxyburate/GLB)
Pathophysiology of solvent misuse
volatile solvents from household and industrial products
aerosol propellants
gases from household
industrial and medical products
nitric oxide
children
short term clinical features of solvent abuse?
dec RR/HR hypoxia drunk feeling - ataxia visual disortion heart failure
long term clinical features of solvent abuse?
hearing loss peripheral neuropathies liver and kidney damage weight loss depression
management of solvent abuse
- Most solvent do not have withdrawal symptoms
- healthy lifestyle advise
- beta-blocker – protect the heart
- support from self-help groups
- abstinence
treatment for Benzodiazepins overdose
Flumazenil
treatment for TCA overdose
IV bicarbonate - reduce risk of seizures and arrhythmias in severe toxicity
treatment for paracetamol overdose
activated charcoal if within 1 horu
NAC
liver transplant
treatment for salicylate overdose
IV bicarbonate
treatment for opioid overdose
naloxone
treatment for lithium overdose
- mild-moderate toxicity may respond to volume resuscitation with normal saline
- hemodialysis may be needed in severe toxicity
• sodium bicarbonate is sometimes used but there is limited evidence to support this. By increasing the alkalinity of the urine it promotes lithium excretion
treatment for warfarin overdose
Vit K _ prothrombin complex
treatment for heparin overdose
protamine sulphate
treatment for beta-blocker overdose
if bradycardia - atropine
in resistant cases - glucagon may be used
treatment for Ethylene glycol (anti-freeze) overdose
fomepizole, an inhibitor of alcohol dehydrogenase, is now used first-line in preference to ethanol
ethanol - works by competing with ethylene glycol for enzyme alcohol dehydrogenase
treatment for methanol overdose
fomepizole or ethanol
hemodialysis
treatment for organophosphate insecticides overdose
atropine
treatment for digoxin overdose
Digoxin-specific antibody - fragmentcalcos
treatment for iron overdose
Desferrioxamine - a chelating agent
treatment for lead overdose
dimercaprol, clalcium edetate
treatment for Carbon monoxide overdose
100% oxygen
hyperbaric oxygen
treatment for cyanide overdose
hydroxocobalamin + combination of amy nitrite, sodium nitrite and sodium thiosulfate
