Poisoning + STOPP-START

Question 1

What is pharmacological toxicity?

Answer 1

• Extension of pharmacological action at a known site
• most often a predictable extension to desired effect
• or secondary effect
• or due to a higher dose than prescribed

Question 2

What is biochemical toxicity?

Answer 2

A drug or active metabolites which cause cellular damage - proteins + enzymes

Question 3

What are the uses of atropine as an antidote?

Answer 3

Treating nerve agent + organophosphate poisoning

Question 4

Management of drug overdose

Answer 4

• immediate actions
• supportive measures
• enhanced elimination
• antidotes
• prevention of absorption

Question 5

What is STOPP-START?

Answer 5

Screen Tool of Older People’s Prescriptions
Screening Tool to Alert to Right Treatment

Question 6

What is the aim of STOPP-START?

Answer 6

Highlight + prevent inappropriate prescribing > reduction in DDIs + ADRs

Question 7

What patient group is STOPP-START validated for?

Answer 7

Patients 65 and over

Question 8

When might it be appropriate to remove/replace a drug on a patient’s prescription?

Answer 8

• no clear evidence of benefit
• risk of bleeding
• risk of toxicity
• side effects.
• condition has improved or stabilised
• DDIs/safety concerns

Question 9

Management of drug overdose in relation to immediate action

Answer 9

• remove person from contact with poison
• vital signs + injury
• history

Question 10

Management of drug overdose in relation to prevention of absorption

Answer 10

• activated charcoal: large absorbent area given as suspension in water
• not suitable for drowsy or comatose patients

Question 11

Why is gastric lavage (stomach pumping) almost never used in prevention of absorption during overdose management?

Answer 11

Risk of aspiration

Question 12

Management of drug overdose in relation to elimination

Answer 12

• continued activated charcoal
• sodium bicarbonate: alkaline diuresis in salicylate poisoning
• haemodialysis
• forced diuresis is not recommended > serious electrolyte imbalance

Question 13

How can atropine be used in the treatment of organophosphate poisoning?

Answer 13

• cholinergic muscarinic competitive antagonist
• blocks acetylcholine

Question 14

Management of drug overdose in relation to antidotes

Answer 14

• competitive antagonists: e.g. naloxone, atropine
• chelating agents: form complex with poison > reducing free drug e.g. cyanide, lead, iron salts
• manipulating drug metabolism: e.g. fomepizole, acetylcysteine
• antivenoms
• digoxin specific antibody

Question 15

How do chelating agents work as antidotes of drug overdose?
Examples

Answer 15

Forms complex with poison > reduces free drug
e.g. cyanide, lead, iron salts

Question 16

When can haemodialyisis be used in Managment of drug overdose?

Answer 16

If drug has small Vd
Only in seriously ill patients

Question 17

How is fomepizole used in overdoses?

Answer 17

• inhibits alcohol dehydrogenase
• can be used in antifreeze + alcohol poisoning

Question 18

What pharmacokinetic + dynamic changes in older people should be considered?

Answer 18

• body composition: increased fat, decreased body water + lean mass
• reduced renal mass + function
• hepatic function + blood flow
• GI absorption + bleed risk
• reduced first pass metabolism

Question 19

What should be thought about during a drug review?

Answer 19

• is medication right for patient?
• time limited medications
• age
• is medication effective
• cost
• appropriate tests to support decisions
• ADRs + DDIs

Question 20

What groups of patients should be particular targeted from a drug review?

Answer 20

• elderly
• co-morbidities
• out-patients
• high risk meds
• frequent admissions to hosptial
• meds prescribed from lots of sources