Medical Toxicology 1

jmanderson's version from 2016-03-08 16:07

theory 1


Question Answer
….. is a substance that does not occur naturally in the human bodyxenobiotic
…… is what our body does to the toxic chemicaltoxicoKINETICS (absorption, distribution, metabolism, excretion, storage)
What are the four components of toxicoKINETICS (ADME)?absorption, distribution, metabolism, excretion, storage)
…… is what the toxic chemical does to our bodytoxicoDYNAMICS (susceptibility and modifying factors – genetics/nutrition)
Risk assessment of the danger of a toxin utilizes the study of …….toxicoDYNAMICS (dose-response data)
Highest dose with NO statistically significant increase in negative health outcomes is calledno observed AE level (NOAEL)
Lowest dose that results in a statistically significant increase in toxicity is calledlowest observed AE level (LOAEL)
How do you calculate reference dose (starting pt for regulating human exposure)?NOAEL/10 for each source of uncertainty
Major source (route) for environmental and occupational toxinsinhalation
Common route for accidental and intentional chemical/drug consumptionoral
(acute or chronic?) exposure is defined as exposure to a toxicant for less than 24 hours.acute
(acute or chronic?) exposure refers to repeated exposure to a toxicant for more than 3 months.chronic

theory 2


Question Answer
the “initiation” of the toxicological process involves the ‘active’ toxin combining with what in the organism?molecular target (M)
The end result of these toxicokinetic processes is a ………………….. dose of the toxicant.biologically effective dose
What relation is important in determining median lethal dose (LD50) in toxicology?quantal dose-response relation
What is ED50? ED99?dose at which 50% or 99% of individuals respond
What is LD50? LD1?dose at which 50% or 1% of individuals have a lethal response
Equation for therapeutic index?TI = LD50 / ED50
Margin of safety equation?LD1 / ED99
Standard safety margin equation?LD1-ED99 / ED99 x 100
What is the dose range in which the response to the drug is below the threshold of adverse response?region of homeostasis

clinical toxicology 1


Question Answer
pre-hospital care for poisoned pt?CAB (chest compressions, airway, breathing), lay pt on LEFT SIDE during transport (slow absorption of drug from GIT)
highest priority in hospital emergency care of poisoned pt?ABCs, later -> Decontamination
what 2 circulatory issues are common in poisoned pts?hypotension, shock
what are 3 ways to provide circulatory support in poisoned pts?volume expansion (NS, dextrose), electrolyte balance, vasopressors (DA, NE, phenylephrine)
Removal of any unabsorbed poison from skin or GIT is called….decontamination
Removal of toxin from GIT should be done within what time frame?< 1 hour
5 methods of GIT decontamination?emesis, gastric lavage, activated charcoal, whole bowel irrigation, cathartics
is ipecac recommended to induce emesis for decontamination?NO
relative contraindications of gastric lavageingestion of corrosive or hydrocarbon agent
what decontamination tx chemically ADSORBS the poison to its surface and is ineffective for FE, lithium, lead, simple alcohols, and corrosivesactivated charcoal
activated charcoal is ineffective for what drug overdoses?Fe, lithium, lead, simple alcohols, corrosives
what decontamination method is used for acute poisoning by sustained-release/enter-coated drugs, heavy metals (Fe, lead, Zn), and packets of illicit drugs?whole bowel irrigation
what is used as the irritant for whole bowel irrigation?Polyethylene glycol electrolyte solutions
3 contraindications for whole bowel irrigation?bowel perforation, obstruction, GI hemorrhage

clinical toxicology 2


Question Answer
What are methods used to enhance elimination of overdosed drug?antidotes, diuresis, hemoperfusion, hemodialysis, manipulate urine pH
what elimination method involves passing large volumes of blood over an adsorbent substance (resins, activated carbon)?hemoperfusion
hemoPERFUSION is used to remove what type of drugs?LIPID SOLUBLE (barbs, hypnotics, sedatives, digitalis)
What elimination method is defined as Extracorporeal blood filtration across a semipermeable membrane using counter current flow between the blood and the dialysate?hemodialysis
hemoDIALYSIS is used to remove what type of drugs?WATER SOLUBLE (methanol, ethylene glycol, ethanol, lithium, salicylates, theophylline)
What are the3 properties of hemodialyzable drugs?LMW, not tightly protein bound, not highly distributed
What are the 4 risks of hemodialysis?anticoagulation, loss of blood elements, fluid/electrolyte disturbances, infection
alkalinzation of urine enhances the ……. form of the drug to enhance eliminationanionic form
if pH>pKa of the drug, what form predominates?anionic form
what do you call the build-up of a higher concentration of a chemical across a cell membrane due to the pKa value of the chemical and difference of pH across the cell membraneion trapping