Exam3Lec2Toxicology Flashcards
What are the toxic gases?
CO and HCN
Carbon Monoxide (CO)
A. Features
B. Exposure
C. MOA
D. Clinical presenations
E. Treatment
A. Features:Colorless, odorless, tasteless
B. Exposure: combusion from cars, fireplaces, furnaces, charcoal
C. MOA: CO binds to hemoblogin lowering unloading of O2 to other tissues and incr O2 affinity at other sites
D. Clinical presentations: hypoxia, lethargy dyspnea, confusion, coma/death
E. Treatment: remove CO source and give 100% O2 via hyperbaric chamber
Cyanide (HCN)
A. Exposure
B. MOA
C. Treatment
A. Exposure: burning of plastics , wool, apple, peach, apricot, cassava “APAC”
B. MOA: Inhibits Cytochrome A3 mediated electron transfer, preventing oxidative phosphyrolation and ATP production.
C. Treatment: Sodium nitrate, Sodium thiosulfate, Hydroxocobalamin(Vitamin B12)
How does treatment work forSodium nitrate, Sodium Thiosulfate, and Hydroxocobalamin?
sodum nitrate or amyl nitrate converts hemoglobin into methmoglobin which binds to cyanide with high affinity to produce cyanmethemoglobin
sodium thiosulfate converts cyanide into less toxic thiocynate
Hydroxocobalmin converts CN to cyanocobalamin which is renally excreted.
A 3 year old boy ingests 30 ferrous sulfate tablets. Which of the following most likely will develop signs of acute toxicity?
A. stomach
B. liver
C. kidney
D. Pancreas
A. stomach
b/c gastroenteritis
What are the toxic inhaled particles?
silica and asbestos
Silica
A. Exposure
B. Toxicity
C. Prevention
A. Exposure: mines, construction sites, stone cutters
B. Toxicity: Silicosis: progressive lung disease that can result in fibrosis and emphysema
C. Prevention: minimize exposiure (no cure)
silica-stones=sites (3 s)
Asbestos
A. Exposure
B. Toxicity
C. Treatment
A. Exposure: inhalation of fibers damage the lungs
B. Toxicity: can cause abestosis, mesothelioma, cancer.
C. Treatment: Prevention and supportive treatment
Rare cancer of the chest wall of peritoneum
Mesothelioma
Interstitial and pleural fibrosis and calcifications
Asbestosis
clinical presenations: SOB, severe coigh and chest pains, progressive disease, no specific treatment.
What are the toxic drugs
1.Methylenedioxymethamphetamine (MDMA)
2.Gamma-hydroxybutyrate (GHB)
3.Acetaminophen
4.Benzodiazepines
5.Opiods
6.Tricyclic Antidepressants
Methylenedioxymethamphetamine (MDMA)
A. Other names
B. MOA
C. Cardiopulmonary effects
D. Neurologic effects
E. Psychologic effects
F. Musculoskelets effects
G. Additional effects
A. Other names: street drug, ecstasy
B. MOA: Causes the release of serotonin (5-HT) and inhibits uptake and synthesis of 5-HT (see incr accumulation of 5-HT in synaptic cleft)
C. Cardiopulmonary effects: tachy and HTN
D. Neurologic effects: Hyperthermia, seizures
E. Psychologic effects: Euphoria, anxiety
F. Musculoskelets effects: teeth grinding, rhabdomyolysis
G. Additional effects: hyponatremia
Treatment of Methylenedioxymethamphetamine (MDMA)
- Hyponatremia: fluid restriction
- Refractory HTN: nitroprusside or phentolamine
- Hyperthermia: aggressive external cooling with ice
- Anxiety and seizures: diazepam
Gamma-hydroxybutyrate (GHB)
A. Exposure
B. MOA
C. Cardiopulmonary effects
D. CNS effects
E. Additional effects
A. Exposure: raves, rape drug
B. MOA: GABAb receptor agonist, incr dopaminergic activity, onset is 15 min
C. Cardiopulmonary effects: hypoxia, brady, hypotension
D. CNS effects: euphoria, deep sleep, coma, hallucination
E. Additional effects: salivation vomitting, hypthermia
Gamma-hydroxybutyrate (GHB) treatment
Bradycardia treament with atropine
Severe withdrawal treatment with pentobarbital
Acetaminophen
A. Toxicity
C. Treatment
A. Toxicity: high amounts can cause liver damage by CYP mediated bioactivation
C. Treatment: N-acetylcysteine is antidote for acetaminophen overdose
* inactivates metabolities
* administer within 8-10 hours to be most effective
can wait longer to administer it b/c the liver and kidney would be damaged
MOA (bioactivation) for Acetaminophen
- Acetominophen can under 2 bioactivation pathways, 1. glucourination and 2. sulfation which both produce non-toxic metabolites of acetominophen
- With overdose of acetominophen, it can undergo bioactivation through CYP enzyme creating NAPQI intermediate
- This intermediate is very electrophilic and interacts with the nucleophiles on the liver and kidney, which can then lead to liver cell death
Benzodiazepines (Diazepam, Chlorodiazepoxide)
A. Toxicity
B. High toxicity
C. Treatment
A. Toxicity: Incr in GABA activity at GABAa receptor, leads to CNS and Resp depression
B. High toxicity : with ETOH, short acting benzos (midazolam), opiods
C. Treatment: supportive, Flumanezil (GABAa antag), Activated charcoal (adsorption)
death is rare
NOT GABAb
Opiods (morphine, heroin, oxycodone, fentanyl, carfentanil)
A. Toxicity
B. Treatment
A. Toxicity: mu receptor agonist causes CNS and Resp depression
B. Treatment: supportive, Naloxone/Naltrexone (mu antags), Activated charcoal
Tricylic Antidepressants (TCA): Amitriptyline, Desiprammine -ine)
A. Toxicity
B. Treatment
A. Toxicity: Incr in norepi and serotonin in synapti cleft, alpha recepetor antag and Na+ channel blocker, tachy
B. Treatment: supportive, sodium bicarbonate (reverse sodium channel blockage), activated charcoal
think “anti-sodium”
A MSP3 student who began interviewing at several prestigious medical schools is studying the effects of toxicants on human neuronal cell lines at the MCOM. Which of the following NT does methylenedioxymethamohetamine incr the most?
A. Glutamate
B. GABA
C. Serotonin
D. Dopamnine
C.Serotonin
A child takes too many iron tablets and is given a chelator to treat his symptoms. He subsequently develops acute respiratory distress. Which of the following was he likely giving?
A. Dimercaprol
B. Penicillamine
C. Succimer
D. Deferoxamine
D. Deferoxamine
The burning of plastics and wool can lead to which of the following toxicities?
A. HCN
B. CO
C. CHCl3
D. CCl4
A. HCN
Which of the following is a GABA receptor agonist?
A. MDMA
B. GHB
C. Morphine
D. TCA
B. GHB
GHB-GABAb
Intermittent phlebotomy is a treatment for chronic toxicity of which of the following?
A. Fe
B. Pb
C. Hg
D. Cu
A. Fe
