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112 Cards in this Set
- Front
- Back
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Mechanism of botulinus toxin
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intereferes with SNAP-25 (SNARE) protein binding in pre-synaptic neuron; no ach release--> flacid paralysis
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treatment for Botulinus toxin
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if early: emesis, lavage, cathartics;
give Equine Trivalent antitoxin (ABE botulinus antitoxin); Support vitals |
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Source of toxin induced gastroenteritis (2-4 hrs after ingestion)
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Staph aureus or salmonella
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Tx for toxin induced gastroenteritis
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Prochlorperazine (anti-emetic)
supportive fluids and ions |
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concerns for Bleaches (Na+ hypochlorite)
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corrosive to GI! do not induce emisis, lavage or acid antidotes
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Tx for Bleaches (Na+ hypochlorite)
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milk, melted ice cream, beaten eggs, antacids;
support vitals remove from skin with H2O |
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Common Organophosphates (insecticides) and mech of action
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Parathion
Malathion cholinomimetic= strong PNS stimulators |
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Symptoms of organophosphate toxicity
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SLUD= salivation, lacrimation, urination, defecation
if severe: diarrhea, pin-point non-reactive pupils, resp difficulty, pulm edema, cyanosis, heart block |
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Tx for organophosphate toxicity
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Pralidoxime chloride (2-PAM) and Atropine
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Mech of 2-PAM
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removes cholinesterase inhibitors from neuronal binding location thereby reactivating acetylcholinesterase enzyme
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mech of organophosphate toxicity
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irreversable cholinesterase inhibitors (prevents breakdown of Ach)
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Mech of Atropine tx for organophosphate toxicity
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Competative antagonist of Ach:
binds to muscarinic acetylcholine receptors. It is an antimuscarinic agent. |
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Carbamates (also insecticides but must distinguish from organophosphates for Tx). What drug is contraindicated in carbamate toxicity?
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2-PAM exacerbates cholinesterase inhibition! Otherwise tx is similar to organophosphates.
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Mech of Strychnine toxicity?
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Antagonist of glycine: shuts off the glycine inhibitory signal --> muscle convusions--> depletion of ATP--> resp paralysis
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tx for Strychnine toxicity?
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IV diazepam (Valium) or succinylcholine
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Mech of diazepam tx?
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Diazepam is a benzo. It binds to the benzo binding site on GABA receptors. Increases the memb potential (makes the interior of the cell more negative) thereby decreasing the depolarizations which lead to seizures/convulsions.
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Other uses of Diazepam? (FYI)
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strychnine, chemical induced convulsions (IV); can also be used in eclampsia when MgSO4 and BP reduction attempts fail. decrease uterine SM contraction long enough to get mom into OR for C-section
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Mech of succinylcholine for strychnine tx?
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inhibits action of Ach via non-competative inhib of nicotinic (M type) receptors)--> decreases EPSPs--> decrease muscle contraction
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Typical activity of Ach binding to nicotinic (M) receptors? (FYI)
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Increase EPSP via increased Na+ and K+ permiability
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Names of typical herbicides?
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Chlorophenoxy compounds (DDT, Agent Orange),
Dinitrophenols, Paraquat |
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Mech of Dinitrophenol toxicity?
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uncoupling of Ox Phos; inc Met rate and temp
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Mech of Paraquat toxicity?
What is it used for? |
undergoes redox-recycling--> ROS injury to lungs;
used to kill off pot plants (If you smoke pot, you might get some paraquat!) |
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Name some halogenated hydrocarbons.
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CCL4, chloroform, methylene chloride, chloroethylene, trichloroethylene, tetrachloroethylene. (some used to be used as general anesthetics)
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Mechanism of halogenated hydrocarbon liver toxicity.
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metabolism by cyto P-450--> ROS generation--> lipid peroxidation leads to increased intracellular Ca2+. Ca2+ is like a kid in a candy shop and just goes around activating enzymes and tearing up the cell
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symptoms of halogenated hydrocarbon intoxication (besides liver toxicity)?
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CNS depressant, cardiac arrhythmias (dt sensitization of myocardium to sympathetic stimulation), renal damage.
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Tx for halogenated hydrocarbons
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remove contaminated clothing, treat symptoms, support vitals
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Mechanism of Methanol metabolism
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Methanol converted to formaldahyde by alcohol dehydrogenase; further metabolized to formic acid by aldehyde dehydrogenase.
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Mechanism of Methanol toxcicity
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formic acid inhibits cytochrome oxidase in the mito--> tissue hypoxia and acidosis
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Characteristic visual disturbances of methanol intoxication
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Like looking through fog and snow (damage to optic nerve may lead to blindness)
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Death by methanol intoxication is usually due to...?
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metabolic acidosis and resp failure; pt may have seizures (hypoxia--> decreased ATP production--> cellular Na+/K+ and Ca2+ pumps fail --> membrane potential decreases--> depolarizations lead to seizures)
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Treatment for Methanol intoxication?
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emesis/lavage, IV ethanol, fomepizole; if pH < 7.2 treat acidosis with sodium bicarb
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effect of EtOH on kidneys?
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ADH inhibition
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Why do you freeze your tail off in Vail if you're drinking there in the winter?
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peripheral vasodilation lets the warm out through your skin
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If your patient shows up with a BAC >500mg% what do you do?
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support vitals, avoid depressant drugs, hemodialysis
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It your alcoholic patient needs to quit what drug can help him feel so lousy that he won't want to drink? How does it work?
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Disulfiram: inhibits acetaldehyde dehydrogenase--> accum of acetylaldehyde will make him feel hungover all the time (Booo!)
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symptoms of isopropyl alcohol toxicity?
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CNS depression, renal damage
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Treatment of isopropyl alcohol toxicity?
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lavage, treat symptoms
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What's the deal with ethylene glycol and fluffy?
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It's in radiator fluid and has a delisous sweet taste that kids and dogs love!
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What organ (besides CNS depression) does ethylene glycol affect? Mech of damage?
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Kidneys. ethylene glycol is oxidized to glycolic acid which is, in turn, oxidized to oxalic acid. Oxalic acid causes CNS depression and binds Ca2+. The crystals deposit in the kidneys.
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Treatment when fluffy or Junior drinks radiator fluid?
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IV ethanol competes with ethylene glycol for the dehydrogenase. You basically force the EG out through the kidneys without allowing it to be metabolized. Fomepizole is also used; alcohol dehydrogenase inhibitor.
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Name some hydrocarbon petroleum distillates
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kerosene, diesel fuel, gasoline, polishes, houshold products
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Mechanisms of petroleum distillate toxicity to lungs? (2)
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pulm irritation dt vapors, severe pneumonitis dt aspiration
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Other symptoms (besides lungs) of petroleum distillate toxicity?
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CNS depression (ingestion or inhalation)
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Treatment of petroleum distillate toxcicity?
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treat symptoms and support vitals
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your suicidal patient shows up after drinking kerosine. Being the bright doc that you are, you know that emesis is contraindicated but you're considering lavage. What must you do first?
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Tracheal intubation.
Must avoid aspiration! |
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Name some aromatic hydrocarbons.
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Benzene, toluene, xylene
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Your patient has been exposed to benzene at his job for 20 years. What two conditions (related to bone marrow) is he at increased risk for?
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aplastic anemia and leukemia
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symptoms of low doses of aromatic hydrocarbons?
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CNS stimulation
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symptoms of high doses or prolonged exposure of aromatic hydrocarbons?
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CNS depression, kidney and liver damage, cardiac arrhythmias dt catecholamine release exacerbated by high exposure
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Your patient shows up after acute, high dose exposure to toluene. he is having convulsions. What do you do?
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IV diazepam. Lavage only if aspiration can be avoided (not likely since he's having convulsions). Do not induce emesis!
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Your patient was cleaning some rust off of his toolbox using a cleaning agent which contained oxalic acid. He got thirsty and decided to drink it. What does it to when ingested?
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corrosive to GI tract--> irritation.
oxalic acid chelates Ca2+ which can lead to muscle weakness, convulsions, collapse and renal deposition of calcium oxilate |
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Calcium oxalate is the most common component of kidney stones.
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makes sense why you would try to precipitate it within the GI tract using calcium.
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Your patient was cleaning some rust off of his toolbox using a cleaning agent which contained oxalic acid. He got thirsty and decided to drink it. His wife calls you to ask what she should do. What's your advice?
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Do not induce emesis as it could cause further GI corrosion. give Ca2+ in any form to help precipitate calcium oxalate within the GI tract. Give him milk, calcium, antacids, etc.
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Your patient was cleaning some rust off of his toolbox using a cleaning agent which contained oxalic acid. He got thirsty and decided to drink it. When he shows up in the ER what do you do?
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Monitor renal labs, force fluids to encourage excretion, give IV calcium gluconate
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Mineral acids are corrosive. We saw lots of them in Gen Chem. Name 4.
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hydrochloric, sulfuric, acetic, perchloric
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A disgruntled undergrad got the brilliant idea to drink sulfuric acid during Gen Chem lab. What's going to happen to his GI tract?
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Inflammation, necrosis--> massive bleeding --> hypovolemic shock
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How are you going to treat the genius sulfuric acid drinking undergrad when he shows up in your ER?
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DO NOT induce emesis! This will exacerbate corrosion of GI tract. Dilute with water, analgesics, Milk of Magnesia (non-specific) and support vitals.
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Soaps, cleansers and drain cleaners are strong alkaline agents. How do you treat alkali intoxication?
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These agents are even more penetrating than strong acids. Treat the same as you would acid toxicity. The patient could die by the same mechanism (shock).
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Use of arsnic in pestacides, herbasides and insecticides is declining but arsnic contamination in drinking water is still a problem in many developing countries (including Bangladesh). What is the mechanism of arsenic and arsine toxicity?
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Arsnic has a high affinity for thiol groups (sulfhydryl groups). Thiols, in the form of cysteine residues, are situated at the active sites of many important enzymes. Toxcisity is due to interference with cellular metabolism.
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how should you treat ingested salicylates or barbituates?
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alkalinize the urine with sodium bicarbonate (this will also increase the pH of blood)
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A 27 year old lady shows up in your ER with an MI. What do you suspect?
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Cocaine
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A strung out adolescent shows up with psychosis. What elicit drug must be ruled out before you call for a psych consult?
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methamphetamine
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Pinpoint pupils.
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opiates
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A farmworker shows up with salivation, lacrimation, urination and defication. What agent is the likely toxin?
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Organophosphates
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A patient shows up with wrist drop and ankle drop. What toxin?
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Lead
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Pt presents with tremor, stomatitis (inflamm of oral mucosa) and emotional instability? What toxin?
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Mercury (Mad as a Hatter!)
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Rural clinic... pt presents with chocolate colored blood. What toxin?
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Nitrites from well water
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Your patient shows up with headache, confusion and lethargy. He has normal O2 sat and has cherry red blood. What toxin?
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CO. a CO-oximeter must be used to detect CO because your O2 sat will appear normal. (The hgb molecules are all bound up and the pulse ox can't tell the diff btw O2 and CO.)
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Besides hgb, what other molecule does CO bind?
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heme group in the cyto P450 enzymes
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WHat direction does CO shift the O2 saturation curve? How do you treat CO toxicity?
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Left.
100% O2. |
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What is an oral chelator used in lead poisoning?
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Succimer
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your patient arrives in a coma and is having seizures. What are your top priorities?
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ABC's Airway, breathing, circulation and seizure control. Give IV diazepam.
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Which toxins do you want to avoid emesis or lavage?
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Mineral acids, strong bases mineral spirits (corrosives). Also avoid emesis in convulsing pts (avoid aspiration).
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Carbamates are used in insectisides. What antidote must you avoid?
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2-PAM
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Iron can destroy the GI mucosa resulting in hypotension, met acidosis and shock. How do you treat iron toxicity >1 hour after ingestion?
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Deferoxamine orally and parenterally (GI and systemic chelator)
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Back in the day, mercury salt compounds were added to animal skins to remove the fur for making felt hats. How should you treat a Mad Hatter who presents with acute mercury intoxication?
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Lavage, emesis, give milk, raw eggs or charcoal. Treat symptoms and support vitals.
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What would you use to treat inorganic mercury toxicity?
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Dimercaprol (BAL: British Anti-Lewisite).
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Dimercaprol will chelate the following heavy metals:
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arsnic, lead, gold and inorganic murcury
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Calcium Disodium Edetate (CaNa2EDTA) used to chelate:
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lead, zinc, alt choice for other metals.
use less than 50mg/kg/day to avoid toxicity. Do not exceed 5-7 days. |
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Treatment for Wilson's disease (copper):
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Penicillamine
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What is the mechanism of cyanide toxicity?
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complexes with ferric iron of cytochrome oxidase: inhib of ox phos--> decreased ATP prod (rapid death)
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What compound will convert methemaglobin back to hemoglobin? (I bet a zillion dollars they ask about this...)
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Methylene Blue- intraerythrocyte enzymatic reducing mechanism
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When would you use sodium thiosulfate?
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Cyanide poisoning. sodium thiosulfate acts as a sulfur donor for conversion by the enzyme Rhodanese
CN- + S (thiosulfate)--> SCN- (excreted) |
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What would be your first move in treating cyanid poisoning? What is the mechanism?
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sodium nitrite or amyl nitrite. These form methemoglobin which competes with cyto oxidase for the CN- ion. Give sodium thiosulfate AFTER IV nitrite administration. Give 100% O2.
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Why are free (airborne) crystalline silica particles dangerous?
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Cause lung damage. predispose to cancer and TB. PTs usually die of right heart failure.
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Why is asbestos dangerous?
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linear fibrosis of the lungs (restrictive lung disease), pleural adhesions, calcifications, tumors
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Where can radon be detected? Why does it matter?
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In basements. Increased risk of lung cancer, especially in smokers.
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Is hemodialysis more effective with toxins having a high Vd or a low Vd?
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Low Vd. If the drug is distributed all over the place (large Vd) hemodialisis is ineffective
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Why would you administer ammonium chloride?
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to acidify the urine and increase excretion of weak organic bases
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What is the role of magnesium sulfate in treating toxicities?
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catharsis (cleansing)
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Why would you give mannitol?
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Increase excretion. It's an osmotic diuretic.
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What common OD would you treat with Acetylcystine? What is it's mech of action?
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acetaminophen OD. acts as a substrate to increase production of glutathione for the reduction of ROS
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Your patient has digitalis toxicity. What do you do?
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give digoxin specific FAB anitbodies
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Your patient has taken too many Vicodans (a benzodiazapene). What do you give her?
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Flumazenil. It competatively inhibits the benzo binding site on the GABA receptor.
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What do you use Naloxone to treat?
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Opioid OD. It is a competative inhibitor of the μ-opioid receptors in the CNS.
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Your patient took a bunch of Beta-blockers? How do you treat her?
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Glucagon. It bypasses the beta adrenergic 2nd msngr system to increase cAMP in the myocardium.
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Pyridoxine is a B6 vitamin. Your patient is being treated for TB. Why would give it to this patient?
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Pyridoxine is given to patients taking Isoniazid (for TB treatment) to combat the toxic side effects of the drug. It is given 10–50 mg/day to patients to prevent peripheral neuropathy and CNS effects that are associated with the use of INH.
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Rx for Non Scheduled Drugs are valid for...
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12 months
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Rx for Non Scheduled Drugs: how many refills?
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unlimited
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Your patient needs a drug. You may phone or fax it in, your DEA number is not required and you may use a pre-printed rx. What type of drug?
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Non Scheduled Drugs only
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What do you know about Schedule I drugs?
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High abuse potential. Cannot prescribe. (MJ, LSD, heroin)
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How long is an Rx for Schedule II drugs (high abuse potential) valid?
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90 days but you can only write for a 30 day supply with no refills.
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When writing for a Schedule II drug, can you use pre-printed scripts? Write more than 1 drug on the rx? Write DEA number?
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No preprinted scripts.
1 drug per script (write out the number of pills to provide). Must include DEA number. |
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Can you phone in a rx for a schedule II drug?
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Only in case of emergency but the written Rx must go to the pharmacy within 7 days.
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How do you classify the following drugs?
Phenobarbitol, methylphenadate, phentanyl, merperidine |
Schedule II
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For schedule III and IV drugs, what's the max number of refills allowed?
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5
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How long is the rx good when prescribing Schedule III, IV and V drugs?
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6 months
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Can you use pre-printed prescriptions for scheduled drugs?
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No.
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What kind of meds do you have to include your DEA number on?
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All scheduled drugs.
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Classify these drugs: zolpidem, diazepam, lorazepam (benzos)
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Schedule IV
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Classify these drugs:
anabolic steroids, ketamine, low dose codine |
Schedule III
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Classify these drugs: Codine less than 200mg, atropine/diphenoxylate
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Schedule V
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