Poisoning and toxicity

Question 1

Explain the concept of Pharmacological toxicity

Question 2

what is Biochemical toxicity

what will dictate the potential harm that may be caused?

Answer 2

A drug or active metabolite which causes cellular damage

The balance of elimination of a drug or metabolites will dictate the potential harm that may be caused

Question 3

some ways to mange overdose?

Answer 3

• prevention of absorption
• enhance elimination
• immediate actions
• prevention of absorption
• antidotes

Question 4

what r the Immediate actions that must take place?

Answer 4

remove person from contact w/ poision

look for vital signs and injury

History from patient if u can, chaperone, evidence-packaging, written notes

Question 5

what Supportive measures must you address:

Answer 5

look for complications that have arisen

Question 6

what would u give to prevent absorption?

when is it not suitable to give? why?

why is Gastric lavage almost never recommended?

Answer 6

Absorption

Activated charcoal-–> large absorbent area given as suspension in water large quantities needed - 10:1

Not suitable for drowsy or comatose patients – ASPIRATION!

due to risk of aspiration

Question 7

give 4 examples of antidotes and their mechanisms?

Answer 7

Competitive antagonists

Naloxone, Atropine

Chelating agents – complex with poison – reduced free drug – sodium nitrate & sodium thiosulfate – cyanide poisoning

Manipulating drug metabolism

Fomepizole, Acetylcysteine

Antibodies antivenom

Digoxin-specific antibody
– binds to digoxin
– preventing action and renal excretion

Question 8

fomepizole?

Answer 8

Question 9

Patients that should be particularly targeted

Answer 9

• Taking lots of medications!
• Complex medication regimens
• Recently discharged
• Frequent admissions to hospital
• Comorbidities
• Medications prescribed from multiple sources
• High risk medications – narrow therapeutic window, known and serious side effect profile
• Long term use of psychotropic drugs

Question 10

Things to be checked during review

Answer 10

• Is the medication right for the patient
• time limited medications – clopidogrel, GORD treatment…. medications that may have been considered during admission but not on discharge – enteral nutrition, hypnotics and benzodiazepines
• age-life expectancy & risk benefit - particularly in this setting
• Is the medication effective? measurable outcome? – HbA1c, BP symptomatic relief in some patient groups or prevent symptoms worsening
• Cost
• Appropriate tests to support decisions

Question 11

Things to be considered during review

Answer 11

DDI

Contraindications – time elapsed – guidelines updated – patient

changes – renal and hepatic function, comorbidities

Side effects – hospital admissions and non-adherence NSAID + PPI – alternative to the NSAID

Concordance – an understanding by the patient of why they are being prescribed a medication

Over the counter and complimentary medicines

Lifestyle modifications – medication may no longer be needed or time to follow-up

Question 12

Recognise when tools such as STOPP-START may be appropriately used in refining medication in polypharmacy?

what age is it used in?

Answer 12

For use in patients (65) years old or older