Lecture 27 - Poisoning Flashcards by Callum Donoher

What is the difference between adverse drug reactions and drug toxicity?

ADR = typical reactions seen at the therapeutic doses of the. Drug

Drug toxicity = associated with effects that occur at supra therapeutic

How well did you know this?

Not at all

Perfectly

What is the most common pharmacological toxicity?

Predictable extension of its desired effect (e.g diuretic leading to hypovolaemia)

How well did you know this?

Not at all

Perfectly

What is a beneficial side effect of loperamide?

Mechanism of action

A type of opioid which works on (agonist) the Mu opioid receptors in the Myenteric plexus leading to decreased gut motility

Helps treat diarrhoea

How well did you know this?

Not at all

Perfectly

What is a benefical side effect of chlorpromazine?

Used as anti-emetic in palliative (is an antipsychotic sedative)

How well did you know this?

Not at all

Perfectly

What are some predictable side effects of:
-warfarin
-insulin
-loop diuretic
-ACh esterase inhibitor

Warfarin = bleeding
Insulin = hypoglycaemia
Loop diuretic = hypokalaemia
-SLUDGE

How well did you know this?

Not at all

Perfectly

What is a secondary effect not related to the primary aim of the treatment of statins?

Rhabdomyolysis

How well did you know this?

Not at all

Perfectly

What is a secondary effect not related to the primary aim of the treatment of thalidomide?

Teratogenic

How well did you know this?

Not at all

Perfectly

What is a secondary effect not related to the primary aim of the treatment of B agonists?

Bronchospasm in asthmatics

How well did you know this?

Not at all

Perfectly

What is a secondary effect not related to the primary aim of the treatment of B blocker?

Bradycardia

How well did you know this?

Not at all

Perfectly

What is often prescribed alongside a chemotherapeutic agent?

Anti emetics

How well did you know this?

Not at all

Perfectly

What is often prescribed alongside methotrexate?

Folic acid

How well did you know this?

Not at all

Perfectly

What is a drug class that can cause resp depression if overdosed?

Opioids

How well did you know this?

Not at all

Perfectly

What is a drug class that can cause myocardial depression if overdosed?

B blockers

How well did you know this?

Not at all

Perfectly

What drug toxicity is seen in overdose of carbamazepine and phenobarbital (works on GABA receptors)?

Respiratory depression

How well did you know this?

Not at all

Perfectly

What drug toxicity is seen in overdose of theophylline (methyl xanthine)?

Convulsions
Arrhythmias

How well did you know this?

Not at all

Perfectly

What is biochemical toxicity?

Destruction of cells or cellular damage from a drug or active metabolite

How well did you know this?

Not at all

Perfectly

What is the mechanism of biological toxicity in paracetamol overdose?

Glutathione gets overwhelmed so toxic metabolites of paracetamol accumulate

How well did you know this?

Not at all

Perfectly

How does Glutathione prevent toxicity from paracetamol?

Donates thiol group

How well did you know this?

Not at all

Perfectly

How do you treat paracetamol overdose?

Give Acetylcysteine which replenishes the thios which glutathione can donate

What is a very toxic side efefct of cyclophosphamide?

Haemorrhagic cystitis

What is cyclophosphamide typically used to treat?

Severe rheumatoid arthritis.

What is given alongside cyclophosphamide to prevent the development of haemorrhagic cystitis?

Mesna and or aggressive hydration

How does Mesna prevent Haemorrhagic cystitis with cyclophosphamide?

Has thiol group for cytoprotection and polar group

Hash a high renal excretion and protection at bladder epithelium

What are the general management principles for treating an overdose?

Prevent absorption
Enhance elimination
Antidotes
Supportive measures

What are the immediate. Actions taken when someone has been poisoned?

Remove person from contact with poison Assess vital signs and injury Good history

What are some methods of preventing absorption of a toxin/poison?

Gastric lovage (stomach pumping) Activated charcoal

Why is gastric lavage rarely used?

Risk of stomach aspiration

What patients is activated charcoal not suitable for?

Drowsy or comatose patients

What are some methods that we can enhance elimination of a poison?

Activated charcoal Sodium bicarbonate (alkkkaline diuresis) for salicylate poisoning Haemodialysis

What are some examples of competitive antagonist antidotes?

Naloxone Atropine

What is the mechanism of action of Naloxone as an antidote?

Antagonist to Mu opioid receptors for opioid overdose

What is atropine used as an antidote for?

Organophosphate poisoning

What is the effect of organophosphate poisoning?

Organophosphate inhibit Acetylcholine esterase leading to very high levels of ACh causing SLUDGE syndrome

How does atropine act as an antidote to organophosphate poison gin?

Blocks Muscarinic ACh receptors decreasing effect of elevated ACh

How do chelating agents work as antidotes?

Form complex with poison reducing free drug

What toxins do chelating agents work as an antidote for?

Cyanide Lead Iron salts

What is a drug that manipulates drug metabolism involving alcohol?

Fomepizole

How does fomepizole manipulate drug metabolism?

Inhibts alcohol dehydrogenase

What is an example of antibodies/antivenoms?

Digoxin specific antibody

What patients should be particularly targeted for drug review?

Elderly Those with comorbidities Pregnant Those just admitted and just about to be discharged

What are some pharmacokinetic and pharmoacodynamic changes in the elderly?

Inc fat, less Body water Renal mass and function reduced Reduced hepatic function and blood flow Lower GI absorption Inc GI bleed risk Reduced barocetpor sensitivity Reduced first pass metabolism Receptor expression changes

What needs to be thought about in a drug review?

Is med right for patient Age, life expectancy Risk Vs Benefit Is it effective Suitable cost Appropriate tests to support decision

What is the STOPP-START programme?

Screening tool used to review drugs patients are taking

What age range is the STOPP-START patients used for?

>65s

What does STOPP-START mean?

Screening Tool of Older Peoples Prescriptions and Screening Tool to Alert to Right Treatement Aims to highlight and prevent inappropriate prescribing