Overdose Flashcards
Features of amphetamine consumption
sympathetic: mydriasis, tachycardia, hypertension, urinary retention
Central: Hyperexcitability, agitation, paranoia
Excessive thirst due to inappropriate ADH secretion
Symptoms of a large amphetamine overdose
Amphetamine psychosis cardiogenic shock and circulatory collapse metabolic acidosis cerebral oedema, hyponatraemia coma
Management of amphetamine overdose
vigorous IV rehydration diazepam if agitated cooling measures Nifedipine if HTN similar principles to serotonin syndrome
Presentation of opioid overdose
Respiratory depression (RR < 8) Sedation Hypotension, tachycardia, pin-point pupils, euphoria, cyanosis
Management of opioid overdose
IV Naloxone - 0.8mg, repeated at 2-3 min intervals
NB if pain relief, this will also be reverse
How is paracetamol metabolised and how does it lead to overdose?
Paracetamol –> NAPQI in the liver
—> NAPQI binds to Glutathione, to be safely excreted
Glutathione stores run out, Toxic NAPQI causes hepatocellular necrosis
What doses of paracetamol will cause overdose
Normal dose = 1g, QDS
<150mg/Kg = unlikely
>250mg/Kg = likely
>12g total consumed = potentially fatal overdose
Timescale of stages of paracetamol overdose
first 24hrs - asymptomatic
>24hrs - N+V, RUQ pain, hepatic necrosis
2-4 days - Jaundice
2-5 days - bleeding from orifices, acute liver failure, potentially acute renal failure
Investigations in paracetamol overdose
Important to quantify exactly how much was take, when and whether it was staggered. +/- alcohol/other drugs
Serum paracetamol levels only taken AFTER 4 hours
If staggered treat immediately
U&Es, creatinine - renal function
Prothrombin Time = best marker of liver function
Measure INR 12 hourly
ALT may ^^^ >1000 IU/L
Management and dosages for Paracetamol overdose
NAC infusion, IV, in 5% dextrose
1) 150mg/Kg, over 15 mins
2) 50mg/Kg, over 4 hours
3) 100mg/Kg, over 16 hours
TOTAL = 300mg/Kg over 21 hours
Features of Tricyclic Antidepressant Overdose
TCAs are ACh-, Na- and Ca- - these produce the side effects and features of overdose
Dry, blurry vision, hyperthermia
cardiotoxicity –> arrhythmias, convulsions coma
Na and Ca blockade leads to Prolonged PR and QRS complexes –> arrhythmias and bradycardia –> cardio-respiratory depression
Management of TCA overdose
IV sodium bicarbonate, 8.4%, 50-100mL
+ Benzos if seizures present (IV lorazepam/diazepam
Timescale of alcohol withdrawal features
6-36 hrs - minor withdrawal - tremor, anxiety, headache, GI upset, ataxia
6-48 hrs - Seizures - generalised tonic clonic
12-48hrs - Hallucinations - visual +/- auditory/tactile
48-96hrs - Delirium Tremens - disorientation, agitated, hallucinating, metabolic acidosis, tachy, febrile, HTN, seizures
Investigations in alcohol withdrawal
Full history - quantifying amount of drink and when stopped
U&Es, serum ethanol, LFTs
FBC, CT head, CXR
Management of alcohol withdrawal
1st Line - Benzos - Chlordiazepoxide - 50-100mg, PO
Vitamin supplementation - Thiamine (vit B1), Folic acid, Mag sulf for seizure prophylaxis
Supportive care as an inpatient
