final Flashcards
what solvents are straight or branched-chain compounds often present in mixtures?
Aliphatic hydrocarbons, such as hexane.
methylene dichloride, chloroform, carbon
tetrachloride, chlorinated ethylenes.
are what types of solvents
Halogenated aliphatic hydrocarbons.
what solvents are used in antifreeze
Ethylene and propylene glycols (PG)
methyl cellosolve is what type of solvent
Glycol ether
———- results from chronic, low- level exposure characterized by nonspecific symptoms (e.g., headache, fatigue, mood disturbances, and sleep disorders) with or without changes in neuropsychological function.
chronic solvent encephalopathy (CSE)
what are toxic effects and TWA (ppm) of benzene
Leukemia / 0.5
what are toxic effects and TWA (ppm) of carbon disulfide
CNS, neuropathy / 10
what are toxic effects and TWA (ppm) of carbon hydrochloride
Liver / 5
Narcosis (CNS depression) is related to the —— and is not related to their chemical structure
solubility of these solvents in lipid
a solvent, such as ——-, may potentiate the adverse effects of others by enhancing their bioactivation
benzene
—–solvent may reduce the toxicity of benzene by competitively inhibiting the bioactivation enzyme systems
toluene
1- what are solvents that lead to liver disease
2- liver lesions are caused by which reactive metabolites of these solvents
1- ethanol and chlorinated hydrocarbons
2-
-carbon tetrachloride → tricholoromethyl
-chloroform → phosgene
-bromobenzene → epoxides
——— toxicity to kidneys from direct cytotoxicity, and blocking of the proximal tubules with the formation of crystals of its metabolite, calcium oxalate
Ethylene glycol
what are lower levels vs higher levels toxic effects of kidney toxicity
-Lower levels: tubular functions, such as glycosuria, amino aciduria, and polyuria
-Higher levels: cell death along with elevated BUN and anuria
CCl4 is toxic to kidneys upon ——- and to liver upon ——–.
CCl4 is toxic to kidneys upon inhalations and to liver upon ingestion
1- what solvents cause CNS toxicity and what are their metabolites
2- what are CNS toxicity effects
1- n-hexane and methyl n-butyl ketone → 2,5-hexanedione
2- Polyneuropathy (motor weakness and numbness) and distal axonopathy pathologically
what type of solvents are known to cause liver cancers
chlorinated hydrocarbons.
also Dioxane which also produces nasopharyngeal cancers
what solvent may damage the retina through its metabolite and affects mainly the part that is responsible for central vision
methanol
what solvent may induce cardiac arrhythmia, probably as a result of sensitization of the myocardium to epinephrine. This is one of the reasons why it has been discontinued as a general anesthetic
Chloroform
what solvent is safe and used as food additives
propylene glycol
w LD50 (32 - 18 mL/kg)
what gas forms carboxyhemoglobin when mixed with Hg
Carbon Monoxide (CO)
also binds to cytochrome oxidase
which gas causes smooth muscle relaxation Hypoxemia, tissue hypoxia, no cyanosis, CO-Hb is cherry red in color
Carbon Monoxide
what HbCO% blood levels show no symptoms ?
-less than 10%
-btw 10-30: headache, dizziness, excertional dyspnea.
-btw 30-50: confusion, N/V, syncope, tachypnea
what’s the most common side effect of chronic low level exposure to CO
memory disturbances
other symptoms:
-tiredness and lethargy
-irritability
-visual impairment
-increased incidence of heart disease on atherosclerosis
what is antidote to CO toxicity
100% oxygen with hyperbaric chambers
what gas is a more potent cytochrome oxidase inhibitor than cyanide
Hydrogen sulfide
what gas is (Neurotoxin)-causes peripheral neuropathy- damage cranial nerve.
Hydrogen sulfide
what is the concentration of hydrogen sulfide that leads to death (respiratory arrest)
> 1000 ppm
what gas causes metabolic acidosis secondary to anaerobic metabolism, hypoxemia and muscle hypoxia
hydrogen sulfide (H2S)
what gas is known to be neurotoxin, causes peripheral neuropathy (cranial nerve damage)
hydrogen sulfide (H2S)
what is the antidote to Hydrogen sulfide (H2S)
-nitrates (in addition to O2 and life support)
-nitrates are antidotal ( cyanide antidote kit) by inducing Meth-Hb - providing a large available source of ferric- heme which has a greater affinity for H2S than does cytochrome oxidase, sequestering sulfide ions freeing cytochrome oxidase
what process causes tachycardia and tachypnea due to cyanide toxicity ?
cyanide stimulation of chemoreceptors in the carotid and aortic bodies
what gas irreversibly combines with the ferric ion of cytochrome oxidase to form a stable complex
Cyanide
(H2S is still a more potent cytochrome oxidase inhibitor than cyanide)
what agents is the new approach used for cyanide poisoning
hydroxocobalamin (vitamin B12)
-combines with cyanide to form cyanocobalamin (Vitamin B12) and the vitamin is excreted by the kidney.
Enhancement of elimination of cyanide: Hemodialysis may be of value in patients who have developed high ——–
thiocyanate (a less toxic compound from cyanide metabolism)
Assessment of the vital signs and the effectiveness of respiration and circulation are the initial concerns during which step of supportive care
Clinical stabilization (first step)
Estimating the —- of the exposure to the poison is frequently the most difficult aspect of the clinical history in the setting of treatment of the poisoned patient
timing
in what step of clinical evaluation does the physician determine the mental status of the patient ?
Physical Examination
-in addition to determining possible additional causes such as trauma or central nervous system infection
in what step of clinical evaluation does the physician determine the toxidromes ?
during the physical Examination
what poisons smell like
(1) bitter almonds,
(2) eggs,
(3) garlic respectively ?
(1) cyanide
(2) hydrogen sulfide and mercaptans
(3) arsenic, OP, DMSO, thallium
what does an elevated anion gap indicate ?
Na – (Cl + HCO3) > 12 indicates metabolic acidosis
-A normal anion gap is <12. When there is laboratory evidence of metabolic acidosis, the finding of an elevated anion gap would suggest systemic toxicity from a relatively limited number of agents (alcohol, methanol and toluene) MUD PILES
metabolic acidosis (anion gap >12) indicates toxicity of:
methanol, alcohols (ethanol ketoacidosis, toluene, iron, lactic acid…)
elevated osmol gap (>10) indicates toxicity of:
osmotically active substance (methanol, ethanol, ethylene glycol, and isopropanol)
what are the most useful radiographs ordered in a case of overdose or poisoning
-chest and abdomen radiographs
-computed tomography (CT) study of the head
what poisons appear as radiopaque liquid in the gut lumen
-lead (in paint)
-halogenated hydrocarbons (chloroform and carbon tetrachloride)
The detection of drug induced non-cardiac pulmonary edema through PLAIN RADIOGRAPHY is associated with serious intoxication with ——-
salicylates and opioid agonists
Significant exposure to ——detected through PLAIN RADIOGRAPHY, has been associated with CT lesions of the brain consisting of low density areas in the cerebral white matter and in the basal ganglia
carbon monoxide (CO)
which method of Prevention of Further Poison Absorption has been limited due to cardio and neurotoxicity risks, as well as lower effectiveness at removing the toxicant than desired
induction of emesis with syrup of ipecac
Acute renal failure and
acid–base and electrolyte disturbances
are associated with which method of Enhancement of Poison Elimination
-acidification of the urine
-that’s why this method IS NOT USED.
what are the agents (poisons) for which hemodialysis has been shown effective as a treatment modality for poisoning.
alcohols, antibiotics, boric acid, metformin, paraldehyde, meprobamate
Protein binding does not significantly interfere with removal by ——.
hemoperfusion
(1) which poison treatment is uncommon and mostly confined to inadvertent drug overdose in a neonate or premature infant due to its risks and complications?
(2) what are those risks and complications?
(1) Plasma Exchange or Exchange Transfusion or pheresis.
(2) allergic type reactions / infectious complications / hypotension.
Multiple dose Activated Charcoal (MDAC) is thought to produce its beneficial effect by interrupting the ——-circulation of drugs
enteroenteric–enterohepatic
The technique of serial oral administration of activated charcoal involves continuing oral administration of activated charcoal beyond the initial dosage every ——-hours.
2 to 4 hours
what are agents for which activated charcoal has been shown as an effective means of enhanced body clearance
Carbamazepine, Dapsone, Digoxin, Salicylates, Theophylline, BARB, Nadolol..
what are the antidotes to the following agents:
(1) digoxin
(2) organophosphate insecticides
(3) cyanide
(1) chelating agents or Fab fragments
(2) atropine anticholinergic at the receptor level
(3) sodium nitrite which interacts with biological systems (hemoglobin to form methemoglobic)
which antidote is used to pharmacologically antagonize at the receptor level
atropine anticholinergic used for organophosphate insecticides
which antidote acts by chemically reacting with biological systems to increase detoxifying capacity for the toxin
sodium nitrite
for cyanide poisoning
to cause formation of methemoglobin, which serves as an alternative binding site for the cyanide ion, thereby making it less toxic to the body