Substance Abuse - Level 1/2/3 Flashcards
How much paracetamol risks severe liver damage?
- Causes severe liver damage if >12 tablets/150mg per kg taken
When to admit paracetamol overdose to hospital?
o If >75mg/kg in less than 1 hour – admit to hospital
Pathology of paracetamol overdose?
o Metabolised by CYP450 enzymes to toxic N-acetyl-p-benzoquinone imine (NAPQI) which is conjugated with glutathione before elimination
o NAPQI accumulation causes hepatocellular necrosis
o Renal failure results from acute tubular necrosis
Risk factors of paracetamol overdose?
o Alcoholics o Drugs which induce hepatic enzymes (St John’s Wort, anticonvulsants, rifampicin) o Malnutrition o Anorexia o Cachexia o HIV
Symptoms and signs of paracetamol overdose?
o Nausea and vomiting, abdominal discomfort
o Untreated patients: Vomiting continues beyond 12 hours Pain and tenderness over liver (from 24 hours) Jaundice (at 2-4 days) Sometimes coma from hypoglycaemia
o Renal Failure
Loin pain, haematuria, proteinuria
o Hepatic Failure
Bleeding
Hyperventilation (metabolic acidosis)
DIC, cerebral oedema
Investigations of paracetamol overdose?
o Bloods - Paracetamol levels, FBC, U&Es, LFTs, INR, glucose o ABG (if appropriate) o ECG (if appropriate) o TOXBASE used for managing drug overdose
- LFTs normal until >18h after overdose
- Prolonged INR (from 24h after overdose)
- ALT and AST raised after 3-4 days
- Bilirubin rises over 5 days
Initial management of paracetamol overdose?
o ABC, clear airway
Simple airway manoeuvres
Oropharyngeal or nasopharyngeal airway if reduced consciousness
Consider ventilation
o Activated Charcoal 1g/kg (max 50g)
If <1h after OD, ingestion >150mg/kg paracetamol
Investigations to performed in paracetamol overdose?
o Bloods – FBC, U&E, LFT, INR, HCO3, ABG
o Blood paracetamol levels at 4h post-ingestion
Further management of paracetamol overdose - what?
IV Acetylcysteine (Parvolex) of 3 consecuative infusions over total of 21 hours
• IVI 150mg/kg in 200ml 5% dextrose over 1h
• IVI 50mg/kg in 500ml of 5% dextrose over 4h
• IVI 100mg/kg in 1L of 5% dextrose over 16h
Further management of paracetamol overdose - when?
- If over-line of treatment
- Presentation of 8-24h after overdose of >150mg/kg
- If over 24 hours, give Acetylcysteine immediately and seek expert help
Further management of paracetamol overdose - if ingestion time unknown, staggered (first dose to last >1 hour) or presentation 8-24 hours from ingestion of >150mg/kg?
Get senior advice
Start Acetylcysteine immediately
When can you discharge patient with paracetamol overdose?
After treatment course of Acetylcysteine and asymptomatic with normal LFTs, serum creatinine and INR
Prognosis of paracetamol overdose?
- Treatment within 8h of ingestion is very effective in preventing liver and renal damage
- Later treatment less effective but worthwhile
Names of opiates?
morphine, diamorphine (heroin), pethidine, codeine, buprenorphine, methadone, etc
Mechanism of opiates?
Opioid agonist, binds to endorphin receptors
Effects of opiates?
o Warm feeling, euphoria, relaxed, analgesic, constricted (pin-point) pupils, untethering from worries or concerns
o Opiate dependency develops in weeks and associated with withdrawal symptoms
Poisoning symptoms of opiates?
o Coma o Respiratory depression Usually within 1h causes death Methadone is long-acting so can be delayed over 24-48h o Pinpoint pupils o Cyanosis, apnoeas o Convulsions o Hypotension o Non-cardiogenic pulmonary oedema – from ‘main-lining’ heroin
Investigations of opiate overdose?
o Bloods Paracetamol levels FBC, U&Es, LFTs, INR, glucose o ABG (if appropriate) o ECG (if appropriate) o TOXBASE used for managing drug overdose
Initial management of opiate overdose?
o Maintain airway
o Ventilate with O2 in bag and mask or ET tube
Management of opiate overdose if patient rousable, not cyanosed and RR>8?
o If patient easily rousable, not cyanosed and RR>8 – observe
Management of opiate overdose if coma, bradypnoea (RR<8)?
Naloxone if coma or bradypnoea (<8breath/min) and monitor for response
400mcg IV, then 800mcg for up to 2 doses at 1 minute intervals, then up to 2mg for 1 dose then review diagnosis
In drug addicts – naloxone precipitates feature of opiate withdrawal
• Diarrhoea and cramps – settle or responds to Lomotil
Further management of opiate overdose?
o Sedate as needed
o Observation for 6 hours after last naloxone dose
o Register opiate addiction and refer for help
Severity of aspirin overdose?
o 150mg/kg – Mild
o 250mg/kg – Moderate
o >500mg/kg - Severe
Early features of aspirin overdose?
o Vomiting, dehydration, hyperventilation, tinnitus & deafness, vertigo, sweating
Other features of aspirin overdose?
o Low GCS, seizures, low BP, heart block and pulmonary oedema
General management of aspirin overdose?
o Consult TOXBASE
o Fluids if low BP
o ECG monitoring - Sinus tachycardia, prolonged QT, dysrhythmias
o Activated charcoal if present within 1 hour if >125mg/kg of aspirin ingested
Investigations of aspirin overdose?
- Bloods
o Paracetamol levels
o Salicylate levels – repeat at 2 hours if large overdose until peak
o FBC, U&E, (AKI, low K, Ca, Mg), LFT, glucose, INR
o ABG:
Initially respiratory alkalosis due to stimulation of CNS respiratory system but then develop metabolic acidosis - Urine
o Catheter, measure pH
