Drug Overdose Flashcards
Define drug ovedose
The ingestion/application of a drug/substance in quantities greater than that recommended
Give examples of drugs that are most frequently used for intentional self-poisoning
- Benzodiazepines
- Analgesics
- Antidepressants
Drugs that are likely to cause overdose include Enzyme inhibitors such as ketoconazole & erythromycin. TRUE or FALSE
TRUE
Drugs that are likely to cause overdose include Enzyme inducers such as Rifampicin and Carbamazepine. TRUE or FALSE
TRUE
State 3 characteristics of drugs with risk of overdose
1) Narrow therapeutic window (Digoxin, Theophylline)
2) High toxic potential (Aminoglycosides)
3) Steep dose-response curve (Warfarin and Sulhonylurea derivatives)
Identify the 6 principles of drug overdose
1) Immediate measures -Evaluation
2) Supportive measures
3) Absorption prevention
4) Elimination
5) Antidotes
6) Psychiatric assessment
Describe the steps of evaluation of a drug overdose
- Recognise the poison
- Identify agents involved
- Assess severity
- Predict toxicity
State 3 absorption prevention methods of drug overdose
- Activated Charcoal
- Gastric lavage
- Induced vomitting
Describe ‘Activated charcoal’ method
- Toxic substances are adsorbed and GI tract absorption inhibited
Name 6 substances that charcoal does not absorb
- Petroleum distillates
- Inorganic acid and alkali
- Alcohol
- Metal ions
- Cyanide
- Lithium
State 3 methods for the elimination of poisons
1) Renal elimination
2) Forced alkaline diuresis
3) Hemodialysis/Haemoperfusion
Fluid and electrolyte disturbances may occur as a result of forced alkaline diuresis. TRUE or FALSE
TRUE
Hemodialysis/Haemoperfusion is used in cases of severe poisoning. TRUE or FALSE
TRUE
Define Antidote
Agents with a specific action against the activity/effect of drugs involved in poisoning cases
How many stages of Paracetamol overdose are there ?
4 stages
Describe symptoms of stage 1 Paracetamol overdose
- 0.5 to 24hrs
- Varies from no symptoms to Malaise
Describe symptoms of stage 2 Paracetamol overdose
- 24 to 72hrs
- Elevations of hepatic aminotransferase
- Elevations of prothrombin time (PT) and total bilirubin
- Right upper quadrant pain. liver enlargement and tenderness
- Oliguria and renal function abnormalities
Describe some symptoms of stage 3 Paracetamol overdose
- 72 to 96hrs
- Jaundice, confusion
- Elevation in hepatic enzymes
- Lactic acidosis
- 25% renal failure
- Maybe death
Describe stage 4 Paracetamol overdose
- 4 days to 2 weeks
- Usually recovery phase that begins by day 4
What is required for paracetamol overdose management for <4 hrs
Activated Charcoal
- May reduce absorption by 50-90%
- Single oral dose of 1g/kg
What is required for paracetamol overdose management for <8 hrs
- Acetylcysteine
- Limits the formation and accumulation of NAPQI
What is required for paracetamol overdose management for <24 hrs
- Oral Methionine
- Protects liver from damage
What is required for paracetamol overdose management for >24 hrs
- Liver transplantation specialist advice
Name a condition where Liver transplantation is life-saving
Fulminant hepatic necrosis
Name 4 indications for liver transplant
1) Acidosis (pH <7.3)
2) Prothrombin time (>100 secs)
3) Creatinine levels>300mcg/L
4) Grade 3 encephalopathy (or worse)
State examples of ADR’s caused by Aspirin
- Interference of metabolism
- GI bleeding and prolonged bleeding
- Activation of respiratory centre
Describe the effects of interference of metabolism
- Prevents formation of ATP/promotes formation lactate and pyruvate
- Inhibits amino acid metabolism
- Inhibits Kreb cycle enzymes/ encourages lipid metabolism and ketogenesis
State 3 effects of Aspirin overdose
- Metabolic acidosis
- Respiratory alkalosis
- Electrolyte imbalance
How is metabolic acidosis brought about ?
Acidic pH promotes movement of salicylate into the tissues
How is Electrolyte imbalance brought about ?
- Increased renal excretion of bicarbonates
- Increased pulmonary insensible losses
- Vomiting
Identify the most important management of Aspirin Overdose
- Urine alkalinization (w/sodium bicarbonate)
What is the result of Urine alkalinization?
Enhanced excretion of ionized, acid form salicylate
Opioids bind to specific opioid receptors in the CNS. TRUE or FALSE
TRUE
State 4 key characteristics of opioid overdose
- Pinpoint pupils
- Respiratory depression
- Decreased level of consciousness
- Hypotension and Bradycardia
Why is ‘pinpoint pupils’ of significance in opioid overdose ?
It acts as an important diagnostic feature in opioid poisoning
Identify the antidote used for opioid overdose management ?
Naloxone
State 4 side effects of Naloxone
- BP changes
- Arrhythmias
- Seizures
- Withdrawal
Pesticides are organophosphate irreversible anticholinesterases (AChE). TRUE or FALSE
TRUE
AChE increases Acetylcholine (Ach) levels. TRUE or FALSE
TRUE
State 3 effects of increased Ach
1) CNS effects
2) Nicotinic signs
3) Muscarinic signs
Identify the antidote used for pesticide overdose management ?
Pralidoxime
Identify 3 types of pesticide overdose management
1) Use of Pralidoxime
2) Clearing airways
3) AChE regenerator (oxime agents)
What is the use of Oxime agents
The acts as AChE regenerators and hydrolyze phosphorylated AChE
Name a drug required simultaneously alongside Pralidoxime to treat muscarinic pesticide excess
Atropine
