Question 7

Describe five (5) potential mechanisms by which poisoning can be fatal and provide
one specific example for each mechanism.

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College Answer

For a good answer candidates were expected to select and describe 5 of a large number of possible mechanisms and provide definite examples for each. Examples of potential mechanism which candidates could select from included any of the following – CNS – Obtundation / Seizures, ( benzodiazepines , Tricyclic antidepressants, Lithium) CVS – Hypotension, Arrhythmia’s (Theophylline, Beta Blockers, Calcium channel blockers, Lithium) Respiratory failure – Hypoventilation, hypoxia (organophosphates due to muscle weakness , any CNS depressant), paraquat with pulmonary fibrosis Hyperthermia – Selective Serotonin Reuptake Inhibitors, Monoamine oxidase inhibitors, Malignant Hyperthermia triggers Cellular hypoxia – Cyanide (Sodium Nitroprusside), Carbon monoxide Massive hepatic necrosis – paracetamol / mushrooms Behavioural changes – Excess Ethanol-> Motor Vehicle Crashes etc , PCP -> flying, self harm Bone marrow / cell death -> colchicine (arrests cells in metaphase) Syllabus: General Pharmacology Reference Text: Multiple sections from standard pharmacology texts