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123 Cards in this Set
- Front
- Back
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What do salicylates cause when they stimulate the respiratory center in the brainstem?
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Hyperventilation and respiratory alkalosis
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How does the kidney respond to this?
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Compensatory renal excretion of bicarbonate
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When excretion of bicarb increases, what function do we compromise?
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Buffering capacity
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Are salicylates acids or bases?
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acids
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How do salycilates affect the kidneys?
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As salicylates compromise buffering capacity, they also impair renal function, l/t accumulation of sulfuric and phosphoric acids.
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What results from a compromise in buffering capacity and increase in acids?
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Metabolic acidosis
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And wait there's more!
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aspirin hasn't done enough mischief......
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How do salicylates affect oxidative phosphorylation?
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They uncouple it from the ETC.
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What does this cause?
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*Impaired ability to generate ATP
*Increased O2 use *Increased CO2 production |
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What happens to all those protons in the ETC?
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Released as heat. Patients will present with fever due to this.
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The release of all this unused energy and lack of substantial ATP generation leads to what?
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Increased demand for glucose
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What happens to get more glucose?
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Increased glycognenolysis, gluconeogenesis, lipolysis, and FA oxidation
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What is the result of increased FA oxidation?
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Increase in ketone bodies
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How do salicylates affect the Krebs cycle?
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They inhibit it
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What is the effect of this?
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Anaerobic metabolism and increased levels of pyruvate and lactate.
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What can this result in?
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Lactic acidosis
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So, after all that, what do patients with acute salicylate OD typically present with?
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Mixed respiratory alkalosis and metabolic acidosis
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What is the DOC for moderate salicylate intoxication?
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IV Sodium Bicarbonate
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What will Na bicarb do?
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Alkanize the urine and promote salicylate excretion
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What is the DOC for severe salicylate intoxication?
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No drug, just hemodiaysis
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Recall the 3 different acetominophen pathways
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1. Directly metabolized to sulfate and glucuronide (non-cyt P450)
2. When enzymes are depleted, cyt P450 metabolism of NAPQI (toxic) via glutathione pathway to cysteine and mercapturic acid 3. When glutathione is depleted, NAPQI (toxic) binds with cellular proteins leading to cell death |
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What is the tx for acetominophen OD?
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N-acetylcysteine supplies cysteine as a precursor for more glutathione and also reacts directly w/NAPQI
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What are the 6 amphetamines and other stimulants?
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Methamphetamine
MDMA (ecstasy) Cocaine Pseudoephedrine Ephedrine Phenylpropanolamine |
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What effects are caused by amphetamines at usual doses?
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Euphoria, wakefullness, sense of power and well-being
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What effects are caused by amphetamines at high doses?
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agitation, acute psychosis, hypertension, tachycardia,
seizures |
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What do seizures cause?
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hyperthermia and rhabdomyolysis
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What does hyperthermia cause?
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brain damage, hypotension, coagulopathy, renal failure
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What is the tx for amph-induced alkaline urine?
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Ammonium chloride for acidification
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What is the tx for amph-induced hyperthermia?
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**phentolamine or nitroprusside
**for very high temperatures: induce neuromuscular paralysis |
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What is the tx for amph-induced tachycardia?
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propanolol or esmolol
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What is the tx for amph-induced seizures?
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IV benzos
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What are the effects of antihistamine OD?
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seizures
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What is a life-threatening effect of TCA's?
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severe CV toxicity
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What is the standard tx for anticholinergic OD?
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physostigmine
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When should physostigmine not be used?
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With TCA overdose
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Why?
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It can aggravate cardiotoxicity, resulting in heart block or asystole
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How to treat anticholinergic OD with agitation?
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benzos or antipsychotics
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Do you know the classic anticholinergic syndrome vignette?
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Red as a beet (skin flush)
Hot as a hare (hyperthermia) Dry as a bone (dry mucous membranes, no sweating) Blind as a bat (blurred vision) Mad as a hatter (confusion, delerium) |
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What happens during B-blocker OD?
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block both B1 and B2
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What is the most potent B-blocker?
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propanolol
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What happens at high doses of propanolol?
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It blocks Na channels and causes cardiac conduction block as well as enters the CNS, causing seizures and coma
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What about other general B-blocker toxicity sx?
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bradycardia and hypotension (most common)
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What about partial agonists (pindolol)?
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tachycardia and hypertension
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How do you tx B-blocker toxicity?
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IV glucagon increases cAMP in cardiac myocytes using glucagon receptors instead of B-receptors (to bypass the B-blockade)
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What are the effects of Ca-channel blockers?
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1. depress sinus node automaticity
2. reduce cardiac output and bp |
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What are the tx for Ca-channel OD?
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1. Ca++ by IV - restores contractility
2. Glucagon and epi - to increase bp in hypotensives and increase hr |
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What is one of the most common drug class to OD on?
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TCAs
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What do they do?
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1. antagonists at muscarinic-R
2. a-blockers, cause vasodilation 3. quinidine like depressant effect on the heart, slowing conduction and depressing contractility |
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How do you treat TCA OD?
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1. NE for hypotension
2. Sodium bicarbonate helps to relieve Na-channel blockade 3. NOT PHYSOSTIGMINE |
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What are the effects of MAO inhibitors when ingested tyramine containing foods?
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severe hypertension
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What is the tx for that?
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phentolamine or labetalol
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What are the effects of MAO inhibitors when taken along with a serotonergic agent?
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serotonin syndrome: hyperthermia, muscle rigidity, myoclonus, death
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What is the tx for 5HT syndrome?
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cyproheptadine, a 5HT receptor antagonist
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What is the tx for 5HT syndrome with agitation, seizures, or rigidity?
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add benzos
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What are the effects of mild/moderate opioid OD?
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lethargy
small pupils bp decreased hr decreased |
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What are the effects of high dose opioid OD?
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coma
respiratory depression apnea sudden death |
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What is the tx?
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naloxone
nalmefene |
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What are the effects of sulfonylureas or meglitinides OD?
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hypoglycemia
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How to treat the hypoglycemia?
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1. concentrated glucose bolus
2. IV octreotide 3. alternate: diazoxide |
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What is the action of octreotide?
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long-acting analog of somatostatin that antagonizes pancreatic insulin release
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What is neuroleptic malignant syndrome?
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hyperthermic disorder seen with antipsychotic drugs
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What are the sx?
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hyperthermia, muscle rigidity, metabolic acidosis, confusion
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What is the antidote?
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1. at < 40C bromocriptine
2. at >40C, bromocriptine and induced neuromuscular paralysis and aggressive external cooling |
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What is main cause of death due to poisoning in the US?
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CO
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How does CO change the O2 saturation curve?
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CO binds to and shifts Hb to the
relaxed state, causing free heme sites to bind to oxygen with high affinity. This shifts the oxygen saturation curve to the left resulting in an inability of the affected hemoglobin to release O2 to the tissues. |
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What are the signs of CO poisoning?
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Cellular hypoxia ans ischemia
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What is the direct effect of CO in cytochromes?
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binding to the reduced iron (Fe) of
cytochromes - inhibiting the ETC |
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What is a lethal dose of CO?
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Values >60% HbCO are fatal
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What is the tx of CO?
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100% oxygen (decrease CO half-life to 80 minutes)
hyperbaric oxygen (decrease CO half-life to 20 minutes) |
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What is the tx of ethanol OD?
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IV dextrose
Thiamine |
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What is methanol metabolized to?
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formalehyde and formic acid
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What are the effects of formic acid?
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severe acidosis
retinal damage blindness |
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What is the tx of methanol OD?
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1. To prevent further metabolism: Fomepizole or ethanol
2. To tx acidosis: IV sodium bicarb 3. Hemodialysis |
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What is ethylene glycol?
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Antifreeze and other chemicals?
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What is it metabolized to?
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Aldehydes and oxalate l/t severe acidosis and renal damage
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What is the tx?
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1. To prevent further metabolism: Fomepizole or ethanol
2. To tx acidosis: IV sodium bicarb 3. Hemodialysis |
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What is bad about organophosphates?
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They undergo ageing an inhibit acetylcholinesterase
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What are the signs of muscarinic effects of organophosphates?
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"DUMMBELSS"
diarrhea urination miosis muscle weakness bronchospasm excitation lacrimation seizures sweating and salivation |
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What is another independent action of organophosphates?
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they phosphorylate neuropathy target esterase causing neurotoxicity - there is no treatment
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What is the tx for organophosphate OD?
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Atropine as an antimuscarinic
Pralidoxime for cholinesterase regenerator Diazepam or Na thiopental for seizures |
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What is the tc for warfarin OD?
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Vitamin K1
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What does cyanide do?
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Binds iron in ferric state and inhibits the ETC
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Hoe to prevent?
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Cyanide Antidote Kit:
1. amyl nitrite pearls 2. Na nitrite 3. Na thiosulfate New Cyanokit: 1. hydroxocaobalamin |
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What sx of acute lead poisoning?
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1. acute abdominal colic
2. CNS changes (adults) 3. encephalopathy (children) |
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What sx of chronic lead poisoning?
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wrist drop
anorexia anemia tremor weight loss GI |
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How is anemia caused?
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decreased production of heme, leading to anemia
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How to tx lead poisoning?
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1. Diazepam for seizures
2. Mannitol/dexamethazone for cerebral edema 3. Dimercaprol, succimer, unithol for chelation |
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What are sx of arsenic poisoning?
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GI
vomiting “ricewater” stools garlicky odor capillary damage with dehydration and shock |
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How to tx?
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Water
electrolytes Unithiol, dimercaprol, succimer for chelation |
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How to tx mercury OD?
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Unithiol, dimercaprol, succimer for chelation
Dimercaprol should not be used in metallic or organic mercury since it redistributes to the CNS |
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How to tx iron OD?
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Deferoxamine
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So, here are just simple slides showing the poison and antidote, for practice.
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here we go
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B-blockers
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glucagon
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Acetaminophen
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N-Acetylcysteine
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Amphetamines & other stimulants
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For hypertension: Phentolamine or nitroprusside
For tachyarrhythmias: Propanolol or esmolol |
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Antimuscarinics (not TCAs)
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Physostigmine
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Arsenic
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Dimercaprol or unithiol
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Benzodiazepines
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Flumazenil
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Cadmium
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Succimer
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Calcium channel blockers
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IV Calcium
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Carbamate anticholinesterases
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Atropine
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CO
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O2
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Copper
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Penicillamine or dimercaprol
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Cyanide
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Amyl nitrite + sodium nitrite + sodium thiosulfate OR hydroxocobalamin
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Digoxin
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Digoxin antibodies
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Ethanol
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Glucose and thiamine
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Heparin
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Protamine
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Iron
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Deferoxamine
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Lead
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EDTA or dimercaprol or succimer
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Malignant hyperthermia
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Dantrolene
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MAO Inhibitors: hypertension
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Phentolamine or labetalol
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Mercury
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Dimercaprol or succimer
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Methanol and ethylene glycol
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Fomepizole or ethanol
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Methemoglobinemia-inducing agents
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Methylene blue
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Neuroleptic malignant syndrome
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Bromocriptine
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Opioids
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Naloxone or nalmefene
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Organophosphate anticholinesterases
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Atropine ± pralidoxime
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Serotonin syndrome
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Cyproheptadine
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Strychnine
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Diazepam or midazolam
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Sulfonylurea- or Meglitinide-induced hypoglycemia
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Glucose ± Octreotide or Diazoxide
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TCAs
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Sodium bicarbonate IV bolus
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Theophylline
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Propranolol or Esmolol
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Warfarin
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Vitamin K1 and plasma or blood
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