Toxicology Flashcards
What is the mechanism of action of organophosphate insecticide poisoning and what is the typical presentation of symptoms?
Inhibits acetylcholinesterase enzyme - accumulation of acetylcholine - cholinergic crisis = SLUDGE S - salivation L - lacrimation U - urinary incontinence D - defecation (diarrhoea) G - gastric upset E - emesis
Typically present very sweaty + vomiting + sinus bradycardia + hypotension + small pupils
What is 1st line treatment for organophosphate poisoning after initial resuscitation?
Atropine (an acetylcholine antagonist!)
What is the principle poison in antifreeze and what can be used as an antidote?
antifreeze = Ethylene glycol
antidote for ethylene glycol / methanol = ethanol or fomepizole
+//- may need haemodialysis
What is the 1st line agent for reversing beta blocker overdose?
1st line = Glucagon
alternative = atropine
In what window is activated charcoal useful in poisoning scenarios?
Within 1 hr of ingestion to reduce absorption of most tablets.
(can give repeated doses after 1hr to aid ELIMINATION of quinine, theophylline, phenobarbitol, carbamazepine and dapsone)
HOWEVER SHOULD NOT USE ACTIVATED CHARCOAL WITH ANYTHING THAT IS CORROSIVE (ALCOHOL, METAL SALTS, CYANIDE, PETROL)
Tx for iron overdose
desferrioxamine
Tx for opioid overdose
naloxone
Tx for warfarin overdose
phytomenadione / vitamin K
Which drugs are associated with causing jaundice?
Nitrofurantoin Erythromycin Isoniazid Aspirin Indomethacin Methyldopa
Which anti-arrythmic causes night glare and metallic taste disturbance?
Amiodarone
Which drugs commonly cause gynaecomastia?
Spironolactone Finasteride Cimetidine (H2 antagonist) Gosarelin Calcium channel blockers
Which drugs commonly cause tardive dyskinesia (repetitive involuntary movements face, neck and limbs)
Metoclopramide
Anti-psychotics
which class of drug is commonly associated with rhabdomyolysis?
statins
Which drug is associated with acquired hearing loss?
gentamicin
Common drug causes of erectile dysfunction?
Alcohol
Anti-hypertensives
Anti-depressents
Nicotine
Ingestion of paraquat -> toxidrome and Mx?
Painful ulcers in oesophagus + mouth + renal failure + pulmonary fibrosis
mx -> activated charcoal and magnesium sulphate laxative
Mx of beta blocker overdose?
1st - > IV atropine to try and correct the bradycardia
Cardiogenic shock not responsive to atropine -> IV glucagon
Anticholinergic toxidrome -> drugs that cause it, the presentation and the antidote?
Anticholinergic agents = tricyclic antidepressents (amitriptyline)
Atropine
Hyoscine
Sedating antihistamines
Presentation = ^ HR/BP/RR/Temp, DILATED pupils, flushed, halllucinating, urinary retention
Tx:
Tricyclic antidepressents = SODIUM BICARBONATE
Others = PHYSOSTIGMINE
Neuroleptic malignant syndrome -> drugs that cause it, the presentation and the antidote?
Causes =
Antipsychotics (typical have ^ risk = Haloperidol, Chlorpromazine, Levomepromazine, Prochlorperazine)
Antiemetics -> Domperidone, Metoclopramide
Presentation = ^ HR/BP/RR/Temp, DILATED pupils, muscle rigidity + rhabdomyolysis, liver + renal failure, hyperkalaemia, metabolic acidosis
Tx = DANTROLENE (reduces muscle rigidity)
Sympatho-mimetic toxidrome?
= cocaine, amphetamine, nicotine, caffeine
Presentation = ^ HR/BP/RR/very high temp dilated pupils, paranoia
Tx -> no specific antidote -> cooling + benzodiazepines
Give immediate aspirin if cocaine associated chest pain
Serotinergic toxidrome?
SSRIs MAOinhibitors Tramadol Amphetamine MDMA / Ecstasy
= high RR/BP/HR/Temp + dilated pupils + tremor/^ reflexes/rigidity
Tx = CYPROHEPTADINE
Withdrawal from sedatives presentation?
= withdrawal from alcohol / benzodiazepines
^ HR/RR/BP/Temp + agitated/hallucinations
Tx = reducing dose of benzodiazepines
Opioid toxidrome?
REDUCED HR/BP/RR/Temp + CONSTRICTED pupils + HYPOreflexia + PULMONARY OEDEMA
= opioids = heroin, morphine, methadone
Tx = Naloxone IV (initially 400 micrograms then titrate up to response (max 4mg)
Sedative toxicity ?
EXCESS of alcohol, benzodiazepines, phenobarbitone
Presentation = constricted pupils, reduced HR/BP/RR/Temp
Tx -> Flumazenil
Cholinergic toxicity?
Cholinergics -> organophosphate poisoning!!
= SLUDGE!!! (excess of parasympathetic activity) S - salivation L - lacrimation U - urination D - diarrhoea G - GI upset E - emesis (vomiting)
CONSTRICTED pupils
Mx = ATROPINE
