Poisoning and Antidotes Flashcards

Question

Most common household poisons

Answer 1

Fabric cleaning liquid tablets, diffusers, bleach, air fresheners, disinfectants

Answer 2

Post major risk to children and toddlers Can cause serious damage in just a short time

Answer 3

Reduction of paracetamol pack sizes, 1998 32 OTC, 16 GSL Led to large reduction in number of poisoning and reduction in number of people needing liver transplant Maximum 100 paracetamol can be sold at any one time in a pharmacy Supermarkets can sell up to 32 capsules/tablets Use professional judgement to decide appropriate quantity to supply and what limits to impose

Answer 4

Child resistant drug containers and safe storage of medicines Medication reviews Patients understanding the dose of medicine the maximum daily dose Disposal of expired and unused medicines Monitoring of sale/sipply of medicines subject to abuse Ensure quality of imported products

Answer 5

Recognise poisoning has occured Establish a patient's drug history ID any agents involved Give advice on antidote use - posions unit/TOXBASE Ensure availability of appropriate antidotes Provide patient info

Answer 6

Ask what the tablets could be - what medication is in the house If she has the tablets, look for at characteristics: marking, size, shape, score down the middle etc Has the child actually taken any Do you know how many they have taken Child's symptoms Can the child communicate Identify tablets Treat the symptoms Tictac is a database that can help medications - may give you one or a list of medicines it vcould be, then work out it could be from there by asking Qs

Answer 7

Some may be managed in primary care Hospital admission criteria - potentially life threatening or delayed action poisons, self-harm/deliberate poisoning Most management is symptomatic, continuous assessment and monitoring Psychiatric/social assessment - accidental or intentional poisoning/self harm Patient often rescuscitated first before identification of agents ingested

Answer 8

Group of symptoms used to identify agents

Answer 9

Opioid overdose: unconscious, hypertension, respitatory depression, pinpoint pupils Anticholinergic: dilated pupils, dry mucous membrane, urinary retention, tachycardia

Answer 10

Gut decontamination to stop medication being absorbed Enhanced elimination Antidotes

Answer 11

Absorbs ingested substances preventing their absorption into systemic circulation Must be fully conscious or have a protected airway Will only work up to the point that medicines are absorbed Most drugs absorbed 20 mins - 1 hour from ingestion so if OD was 3 hours ago, there is no point giving charcoal Activated charcoal is ideal up to 1 hour, max 2 hours

Answer 12

Cleanses the entire bowel through enteral administration of large amounts of an osmotically balanced solution like polyethelyene glycol Used for high doses of iron, lithium

Answer 13

e.g. NAHCO3 Increases eliminaiton of weak acids like aspirin Administration titrated against urinary pH Try keep urinary pH between 7.5-8.6 to prevent aspirin being ionised and reabsorbed in renal tubules Blood gases and K levels must be measured

Answer 14

Remove blood and put it back in Only used for a limited subset of drugs/chemicals e.g. severe aspirin, lithium, ethylene glycol, methanol

Answer 15

Substances that can counteract a form of poisoning by a variety of mechanisms: - forming an inert complex with the poison - accelerating detoxification of poision - reducing rate of conversion of the poison to a more toxic compound - competing with the poison for essential receptor sites - blocking essential receptors through which the toxic effects are mediated - bypassing the effect of the poison

Answer 16

Used for digoxin toxicity Forms an inert complex with digoxin and it is no longer toxic and will be excreted to the body Binds in a 1:1 ratio - need to work out how much a patient has taken, and from that work out how much Digi-fab to give Digoxin is a potent inhibitor of Na/K-ATPase to toxicity will result in strong inhibition of it = increased intracellular sodium = increased intracellular calcium = increased conttacility and tachycardia

Answer 17

Normal therapeutic dose: ~95% metabolised via glucuronide mechanism and forms a conjugate which is excreted in urine, only ~5% forms the toxic NAPQI metabolite When too much paracetamol is taken, the other pathway become satruated meaning a lot more of the paracetamol is metabolised ot the toxic ANPQI, causing hepatoxicity NAC replenishes gutathione to accelerate detoxiifcaiton of paracetamol - does this by metabolising to glutathione - the glutahtione will bind to NAPQI to form to non-toxic metbaolites as well to force more through the other pathway

Answer 18

- Metabolites of ethylene glycol are toxic e.g. oxalic acid clogs renal microcirculation and acute tubular necrosis e.g. formic acid causes damage to retina leading to blindness e.g. glycolic acid causes metabolic acidosis - antidote: ethanol or fomepizole - reduces rate of conversion of ethylene glycol ot toxic metabolites - either will give 40% alcohol or give femepizole (competitive antaognist, more expensive)

Answer 19

Direct inhibitor of opioid receptors Has high affinity for opioid receptors in brain Displaced opioid from the receptors and it will be metabolised and excreted from bodt Has short half life so may need repeated doses or infusion depending on how much morphine was given to patient

Answer 20

By passes effect of warfarin inhibiting VKOR Warfarin commonly implicated in poisoning When you give warfarin, it blocoks VKOR, stopping conversion of vit K to reduced vit K which is involved in clotting factors Too much warfarin = not enough clotting factors = increased risk of bleeding and bruises Give vitamin K to help regenerate the required clotting factors Does not inhibit warfarin