Poisoning

Question 1

What is the definition of poisoning and the different types out there

Answer 1

The exposure to a drug or chemical or pollutant in enough quantity to produce an adverse effect

Acute: immediate attention and care from large exposure to chemical

Chronic: Slow build up overtime, long time exposure to heavy metals or prolonged use of medicine

Question 2

Describe accidental poisoning

Answer 2

Makes up majority of poisoning

Children- house hold chemicals or parent’s medication

Duplication of therapy- lemsip- do not take paracetamol with it

Confusion over doses

Counterfeit drugs- can contain harmful ingredients or contaminates
- Parallel imports, internet, manufactured somewhere unsafe

Question 3

Describe deliberate poisoning

Answer 3

To cause others harm

Overtaking medicines for benefits- thyroxine for weight loss
- Works by causing hyperthyroidism which speeds up metabolism

Risk of tachycardia, angina and osteoporosis

Question 4

Describe suicide

Answer 4

Self administration of a prescribed or OTC medicine or an illicit drug

Most patients taken more than one drugs and alcohol is the commonly implicit second agent

Question 5

Describe occupational poisoning

Answer 5

Chemicals found in place of work

For example:
X rays, lead, mercury, asbestos, pesticides, noxious fumes, solvents, corrosive agents, fertilisers, bites by snakes

COSSH risk assessment necessary

Question 6

Describe environmental poisoning

Answer 6

Air
Water
Soil
Pollution

Question 7

Describe nicotine poisoning

Answer 7

Highly toxic by ingestion, inhalation and skin contact

Little as 40mg nicotine is fatal in adult

Varying strengths from 6mg per mL to 36mg per mL so small amount can be threatening

Question 8

What are the signs of nicotine toxicity

Answer 8

Stimulant

Increases heart rate tachycardia

Question 9

What are some side effects of nicotine

Answer 9

Headache
Dizziness
Increased or decreased heart rate
Increased blood pressure
Tachycardia
More arrhythmias
GI- nausea, dry mouth, diarrhoea, cancer
Joint pain
Circulation- increased clotting tendency, atherosclerosis

Question 10

What are the most common household poisons

Answer 10

Surfactants + detergents
Bleaches
Ethylene glycol
Batteries 
Silica gel
White spirit
Cyanoacrylate

Question 11

What are the most common drugs taken in overdose

Answer 11

Paracetamol
Ibuprofen
Salicylates- aspirins
Citalopram
Diazepam
Zopiclone
Compound analgesics
Fluoxetine
Tramadol
Amitriptyline

Question 12

What is the pharmacist’s role in prevention of self poisoning

Answer 12

Limting stock pile of medicines
Reviewing home medicine's cupboard
Safe storage of medicines and caustic substances
Child resistant drug containers 
Foil wrapped drugs
Dispose of expired and unused medicines

Prescriptions monitored carefully
Patients understanding of medicine doses and maximum daily dose
Reduction of paracetamol pack sizes
Co-proxamol withdrawn from market
Removal of counterfeit or contaminated products
Ensure quality of imported products

Question 13

What is the pharmacist’s role in treating poisons

Answer 13

Recognising poison has occurred

Establishing a drug history

ID any agents involved

Advice on antidote use- poisons unit or TOXBASE (online database with medicine information)

Ensure medicines are available for appropriate antidotes

Provision of patient information

Question 14

How do you manage poisons

Answer 14

Psychiatric and social assessment

Careful recording of information

Admission criteria:
Potentially life threatening or delayed action poisons
Self harm or deliberate poisoning
Seek advice from Toxbase if unsure

Monitor patient- liver function, renal function, blood levels, pulse

Question 15

Describe the general treatment of poisoning

Answer 15

Symptomatic and supportive care

Check for infection and/or trauma and metabolic derangements

Continuous assessment and monitoring

Case specific management

Patients often resuscitated first before identification of agents ingested

Cluster of symptoms and signs- toxidrome
- Patient may have pin point pupils, reduced BP- opioids
Tricyclic anti-depressants- anti-muscarnic effects

Question 16

Describe the gut decontamination treatment

Answer 16

1. Only used where it presents early, fully conscious, significant risk of harm- tube down someone throat, warm water and pumping stomach content back through tube
2. Induced vomiting with ipecacuanha or performing gastric lavage (nasty drink)- no evidence of impact on outcome- taken within 30 minutes of exposure
3. Activated Charcoal- absorbs ingested substances to prevent absorption into systemic circulation- used within an hour or 2 hours of ingesting medicine
4. Whole bowel irrigation- polyethylene glycol- high iron doses, lithium, SR prep, body packers- flushing out via toilet

Question 17

Describe the enhanced elimination treatment

Answer 17

1. Urinary alkalisation- NaHCO3
   Increases elimination of weak acids e.g. aspirin
   Administration titrated against urinary pH
   Blood gases and K must be monitored
2. Haemodialysis and haemoperfusion (blood pumped via colon with absorption properties)
   - Limited subset of drugs and chemicals like severe aspirin, lithium, ethylene glycol, methanol

Question 18

Describe the antidote treatment

Answer 18

Forming inert complex with poison

Accelerating detoxification of poison

Reduction in rate of conversion of poison to more toxic compound

Competing with poison for more essential receptor sites

Blocking essential receptors which means toxic effects are mediated

Bypassing poison effect

Question 19

Explain how digi-fab works

Answer 19

Forms an inert complex with digoxin

The digoxin (xenobiotic) binds onto the antibody antidote to form an inert compound

Question 20

Explain how N-acetylcysteine works

Answer 20

Used in paracetamol overdose- accelerates detoxification of paracetamol

The glucuronide sulfate stores are depleted so paracetamol doesn’t get converted into non toxic metabolite and gets converted to NAPQI (toxic)

The N-acetylcysteine works by replenishing stores of Glucuorinide which detoxifies paracetamol

Question 21

Explain the poisoning of ethylene glycol

Answer 21

Anti-freeze poisoning
Calcium oxalate crystals form that precipitate in blood stream to clog renal microcirculation causing acute tubular necrosis

Oxalic acid- responsible for nephrotoxicity

Formic Acid- toxic to retina and causes blindness

Glycolic acid- responsible for metabolic acidosis

Question 22

Explain how ethanol or fomepizole is used against ethylene glycol

Answer 22

Competes against rate of conversion of ethylene glycol to toxic metabolites- 40% used to compete with it

Question 23

Describe how naloxone works

Answer 23

Stronger affinity to opioid receptors like heroin or oxycodone- so it knocks it off receptors for short time (30 to 90 mins) to allow person to breathe again and reverse dose

Question 24

Describe the use of phytomenadione

Answer 24

Competes with warfarin for essential receptor sites

Name: Vitamin K

It is a vitamin K antagonist for warfarin as warfarin is structurally similar to vitamin K

Question 25

Explain the use of glucagon

Answer 25

Bypasses blocked beta receptor for overdose in beta blockers- increases calcium levels

Glucagon bypasses effect, binds at glucagon receptors, blocks adenylcyclase cycle to reduce calcium levels