Drug Overdose Flashcards
(35 cards)
What are 2 symptoms of paracetamol overdose?
N+V
Asymptomatic
Give 2 groups at increased risk of paracetamol overdose
Those on enzyme inducers e.g. Rifampicin, Phenytoin, Carbamazepine, St Johns Wort
Malnourished/ not eaten for a few days
What is the management of paracetamol overdose?
Activated charcoal if <1h
N acetylcysteine infusion delivered over 1h
Liver transplantation
What are the 4 indications for N-acetylcysteine in paracetamol OD?
plasma conc. on/ above a single tx line joining points of 100 mg/L at 4h
Staggered OD or doubt over time of ingestion, regardless of plasma concentration
Pt presenting 8-24h after ingestion of an acute OD of >150 mg/kg, even if plasma conc not yet available
patients who present >24h if they are clearly jaundiced or have hepatic tenderness/ ALT is above upper limit of normal
What adverse effects may be seen when infusing N-Acetylcysteine for paracetamol OD?
How should this be managed?
Anaphylactoid reaction (non IgE mediated mast cell release)
Stop the infusion, then restart at a slower rate.
What are 5 symptoms of salicylate overdose with mild toxicity?
N+V
Epigastric pain
Tinnitus + deafness
Dizziness
Lethargy
What are 3 symptoms of salicylate overdose with moderate toxicity?
Sweating
Fever
Dyspnoea: Hyperventilation (centrally stimulates respiration)
What are 3 symptoms of salicylate overdose with severe toxicity?
Confusion
Convulsions
Coma
What acid base picture is found in salicylate overdose?
mixed respiratory alkalosis + metabolic acidosis
Give 4 signs of salicylate overdose on examination
Warm peripheries + bounding pulse
Tachypnoea + hyperventilation
Cardiac arrhythmia
Acute pulmonary oedema
What bedside investigations should be performed in salicylate overdose?
Basic obs: tachycardia + taachypnoea
ECG: monitor for arrhythmia
CBG: exclude hypoglycaemia/ ketoacidosis
ABG: Acid base balance
What bloods should be taken in salicylate overdose?
Salicylate conc. >,2h after ingestion + repeat every 2h
Paracetamol conc.: identify mixed OD
FBC
U+Es: Electrolyte disturbances
LFTs: Hepatic dysfunction
Coagulation: INR + PT may be increased in hepatic dysfunction
What peak salicylate levels define mild, moderate and severe salicylate toxicity?
Mild: <300 mg/L
Moderate: 300 to 700 mg/L
Severe: >700 mg/L
Describe initial management of salicylate overdose
A-E
Activated charcoal if <1h
IV NaCl
K+ replacement
IV sodium bicarbonate (urinary alkalisation, enhances excretion in urine)
Give 2 indications for haemodialysis in salicylate overdose
Serum conc > 700mg/L
Tx resistant Metabolic acidosis
Give 4 complications of salicylate overdose
Acute respiratory distress syndrome
Seizures
Drug-induced hepatitis
Cardiac arrest (prolongation of QT)
What are 3 symptoms/ signs of opioid overdose?
Bradypnoea (resp. depression)
Pinpoint pupils (miosis)
Drowsiness/ Coma (altered mental status)
Give 4 measurable signs of opioid overdose?
Bradycardia
Hypotension
Hypothermia
Constipation (reduced BS)
What is used for management of opioid overdose?
IV/ IM Naloxone
(Rapid onset, relatively short duration of action, may need to repeat/ infusion)
What are 8 symptoms of benzodiazepine overdose?
Reduced level of consciousness (inc. coma)
Resp. depression: can result in hypoxia +
inadequate tissue perfusion.
Ataxia + dysarthria
Nystagmus
Hypotension
Bradycardia
Rhabdomyolysis
Hypothermia
What can coma lead to in Benzodiazepine overdose?
Loss of airway tone + reflexes leading to hypoxia
Describe management of Benzodiazepine overdose
A-E assessment
Maintain airway
Supportive e.g. fluids
Activated charcoal if <1h since ingestion if awake
+/- Flumazenil
When is flumazenil use indicated in a benzodiazepine overdose?
- CNS depression so severe requires ventilation
- Confidence only benzos have been taken (e.g. no possibility of a mixed OD)
- Patient is not known to be benzo dependent
Why must 3 conditions be met for flumazenil to be used in benzodiazepine overdose?
Use outside these conditions risks precipitating seizures
(e.g. if a patient has also taken TCAs)
v difficult to treat due to the GABA antagonism caused by Flumazenil.
