CHAPTER 450 POISONING AND DRUG OVERSE Flashcards
(178 cards)
1
Q
it refers to the development of dose-related adverse effects following exposure to chemicals, drugs, and other xenobiotics
A
poisoning
2
Q
age prone to poisioning
A
<6 years old
3
Q
major reason for increased number of poisoning deaths
A
opoids
4
Q
unintentional exposures include
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improper use of chemicals at work or play label misleading product mislabel mistaken identification unlabeled chemicals uninformed self medication dosing errors elderly
5
Q
most common reported reason for intentional poisoning
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recreational use of ethanol
6
Q
pharmaceutical agent most often implicated in fatal poisoning
A
acetaminophen
7
Q
leading cause of death from poisoning
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carbon monoxide
8
Q
correct diagnosis established by
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history, physical examination, routine and toxicologic laboratory evaluations and clinical course
9
Q
history includes:
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time route duration circumstances the name and dose chemical involved the time of onset nature and severity of symptoms time and type of first aid used medical and psychiatry history
10
Q
if the px is confused or comatose suspect?
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history of psychiatry problems
recent changes of economic and relationship status
work with chemicals
11
Q
what is body packing or body stuffing
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ingesting or concealing drugs in the body cavity
12
Q
relevant information may be available from
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family friends paramedics police pharmacist physicians employers
13
Q
it focuses the vital signs, and the systems
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physical examination
14
Q
neurologic status includes the:
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documentation of the neuromuscular abnormalities such as dyskinesia, dystonia, fasciculations, myoclonus, rigidity and tremors
15
Q
examine the eye for:
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nystagmus and pupil size and reactviity
16
Q
examine the abdomen for:
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bowel activity and bladder size
17
Q
examine the skin for:
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burns bullae color warmth moisture pressure sores puncture marks
18
Q
what to do when history is unclear?
A
examine all the orifices for the presence of chemical burns, and drug packets
19
Q
it also provide important diagnostic clues
A
odor of breath
vomitus
color of the nails and skin and urine
20
Q
how to diagnose a poisoning in cases of unknown etiology
A
relies on pattern recognition
21
Q
how to detect pattern recognition to diagnose poisoning in unknown etiology
A
first: assess the pulse, blood pressure and respiratory rate and temperature and neurologic status and characterized the overall physiologic state as stimulated, depressed, discordant or normal
second: identify the pathophysiologic patterns or toxic syndrome (toxidrome)
third: identify the particular agent involved by looking at the unique poison specific physical or ancillary test abnormalities
22
Q
most reliable prognosticator of poor outcome in poisoning from stimulants
A
temperature elevation
23
Q
what are the 4 physiologic state
A
stimulated
depressed
discordant
normal
24
Q
stimulated physiologic state is characterized by
A
increased pulse, bp rr, temp and neuromuscular activity
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stimulated physiologic state reflects the
symphathetic, anticholinergic or hallucinogen poisoning or drug withdrawal
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feature of all stimulants and is most marked in anticholinergic poisoning since the pupillary reactivity relies on muscarinic control
mydriasis
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anticholinergic syndrome is characterized by:
hot dry flushed skin
decreased bowel sounds
urinary retention
other: diaphoresis, pallor and increased bowel activity with nausea, diarrhea
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findings that suggest sympathetic poisoning
increased vital signs and organ ischemia
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selective alpha adrenergic stimulants such as decongestants can cause
reflex bradycardia
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selective beta-adrenergic stimulants such as asthma therapeutics can cause
hypotension
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ergot alkaloids can cause
limb ischemia
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phencylidine and ketamide can cause
rotatory nystagmus
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cocaine can cause
delayed cardiac contraction
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what do seizures suggest
sympathetic etiology
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state characterized by mixed vital signs and neuromuscular abnormalities
discordant physiologic state
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cause of depressed physiological state
functional sympatholytics (agents that decrease cardiac function and vascular tone)
cholinergic such as muscarinic and nicotinic agents
opiods
sedatives
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feature that is most pronounced in opiods and cholinergic poisoning
miosis
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other clues that may suggest physiologic depressed state
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cardiac arrhythmias
conduction disturbances
mydriasis
nystagmus
seizures
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39
what can cause arythmias and conduction disturbances
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antiarrhythmias
calcium channel blocker
digitalis
glycosides
propoxyphene
cyclic antidepressants
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40
what can cause mydriasis
tricyclic antidepressants and some antiarrhymics, meperidine and diphenocylate atropine such as lomotil
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what can cause nystagmus
sedative hypotics
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what can cause seizures
cholinergic agents
propoxyophene
cyclic depressants
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physiologic state characterized by decreased pulse, bp, rr, and temp and neuromuscular activity
depressed physiologic state
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cause of normal physiologic state
non-toxic exposure
psychogenic illness
poisoning of toxic time bombs that are slowly absorbed and slowly distributed and require metabolic activation
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laboratory result most common in advanced methanol, ethylene glycol and salicyate intoxication
increased anion gap metabolic acidosis
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what happens when there is increased blood levels of bromide, calcium, iodide, lithium or magnesium
abnormally low anion gap
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a difference of >10 mmol per liter between serum osmality suggests the presence of low molecular weight solute such as acetone, alcohol , glycol, and ether, or sugar
a difference of >10
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ketosis suggest of
acetone, iso alcohol, salicylate poisoning or alcoholic ketoacidosis
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hypokalcemia suggest of
beta-adrenergic blocker, caffeine, diuretics, theophylline, toleune
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hyperkalcemia suggest of
poisoning of alpha adrenergic agonist
beta adrenergic blocker
cardiac glycosides
fluoride
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hypocalcemia suggest of
ethylene glycol
fluoride
oxalate poisoning
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result of ECG in px poisoned with alpha adrenergic agonist, beta blockers, calcium channel blockers and cholinergic agents
bradycardia and atrioventricular block
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QRS and QT interval prolongation is caused by
hyperkalemia
antidepressants
membrane active drugs
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ventricular tacycardia suggests
poisoning with cardiac glycosides
fluorides
membrane active drugs
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radiologic result in px with posoining of carbon monoxide, cyanide and opiods
pulmonary edema
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aspiration pneumonia is common in px with
coma
seizures
petroleum distillate aspiration
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what can be used to rule out and confirm suspected poisoning
toxicologic analysis
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what can be used to rule out and confirm suspected poisoning
toxicologic analysis
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screening test that should not be used because it cannot confirm the exact identity of the detected substance
rapid qualitative hospital-based urine test
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useful for diagnostic purposes
response to antidotes
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resolution of altered mental status and abnormal vital signs within minutes of IV administration of dextrose, naloxone, or flumazenil is diagnostic of
hypoglycemia
opoid poisoning
benzodiazepine intoxication
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grade of physiologic stimulation that is anxious, irritable but the vital signs are normal with diaphoresis with flushing and pallor, mydriasis and hyperflexia sometimes present
grade 1 physiologic stimulation
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grade of physiologic stimulation that is agitated may have confusion or hallucinations but can converse and follow commands but the vital signs are mild to moderately increased
grade 2 physiologic stimulation
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Grade of physiologic stimulation that is delirious, unintelligible speech, uncontrollable motor hyper-activity moderately increased vital signs and tachyarrhythmias are possible
grade 3 f physiologic stimulation
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grade of physiologic stimulation that is in coma, seizures and in cardiovascular collapse
grade 4 physiological stage stimulation
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grade of depressed if the px is awake, lethargic or sleeping but arousable by voice or tactile stimulation and able to converse and follow commands but may be confused
Grade 1 physiologic depression
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grade of physiologic depression if the px responds to pain but not to voice can vocalize but not converse with the spontaneous motor activity present with brainstem reflexes intact
grade 2 physiologic depression
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grade of physiologic depression that is unresponsive to pain, spontaneous motor activity absent with brainstem reflexes depressed, motor tone, respirations and temperature decreased
grade 3 physiologic depression
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grade of physiologic depression that is unresponsive to pain, flaccid paralysis, brainstem reflexes and respirations absent with cardiovascular vital signs decreased
grade 4 physiologic depression
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what are the treatment goals for poisoning and drug overdose
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support of vital signs
prevention of further poisoning absorption
enhancement of poison elimination
administration of specific antidotes
prevention of re-exposure
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what is the highest priority in the pre-toxic phase?
decontamination and treatment are solely based on history and pe
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when history is not obtainable and poison is causing delayed toxicity what is the appropriate best thing to do?
blood and urine samples were sent for toxicologic screening and quantitative analysis
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what is toxic phase
interval between the onset of poisoning and its peak effect
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management during toxic phase
based on laboratory and clinical findings
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when does the effect of overdose manifested
begin sooner and peak later and last longer than they do after a therapeutic dose
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what is the first priority
resuscitation and stabilization
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what to give in px with altered mental status that has come and seizures
intravenous glucose
naloxone
thiamine
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measures that enhance the decontamination of salicylates
urinary alkanization
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enhance decontamination in metals
chelation therapy
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what is the goal of supportive therapy
maintain the physiologic homeostasis until detoxification is accomplished and to prevent and treat secondary complications
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indications for admission in intensive care unit
patients with severe poisoning (coma, respiratory depressionm hypotension, cardiac conduction abnormalities, cardiac arrythmias
those needing close monitoring
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respiratory care to prevent aspiration of gastrointestinal contents especially in those with CNS depressions and seizures
endotracheal intubation
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respiratory care for px with respiratory depression or hypoxemia and for facilitation of therapeutic sedationn or paralysis of patients in order to prevent or treat hyperthermia, acidosis and rhabdomyolysis associated with neuromuscular hyperactivity
mechanical ventilation
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oxygenation and ventilation is best determined by
pulse oximetry and arterial blood gas analysis
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not a reliable indicator for the need of intubation
gag reflex
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if the px hypotension is unresponsive to volume expansion and appropriate next step is?
treatment with norepinephrine and epinephrine and high dose dopamine
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what should be considered in px with severe but reversible cardiac failure
intraaortic balloon pump counterpulsation
| venoarterial or cardiopulmonary perfusion techniques
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treatment for sympathetic hyperactiviity
benzodiazepine
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treatment for anticholinergic posoining
physostigmine
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treatment for ventricular arrhythmia
sodium bicarbinate
lidocaine
phenytoin
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treatment in px with torsades de pointed and prolonged QT intervals
magnesium sulfate and overdrive pacing
90
treatment for severe cardiac glycoside poisoning
magnesium and anti digoxin antibodies
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seizures caused by excessive stimulation of catecholamine receptors is treated with
agents that enhance GABA activity such as benzodiazepine and barbiturates
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seizures caused by isoniazid are treated with
pyridoxine
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what is contraindicated in toxicologic seizures
phenytoin
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serotonergic receptor overstimulation is serotonin syndrome is treated with?
cyproheotadine
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the average time from ingestion to presentation of adults
>3 hours
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the average time of ingestion to presentation of children
>1 hour
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preferred method of gastrointestinal decontamination that has fewer contraindications and complications
activated charcoal
98
mechanism of action of charcoal
the charcoal adsorbs ingested poisons within the gut lumen allowing the charcoal toxin complex to be evacuated in stool
99
what compounds that are not well absorb in charcoal
charged ionized chemicals such as mineral, acid, alkalis, and highly dissociated salts of cyanide, fluoride, iron, lithium and other inorganic compounds
100
side effects of charcoal
nausea, vomiting, and diarrhea or constipation and prevents the absorption off orally administered therapeutic agents
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complications of charcoal
mechanical obstruction of airway, aspiration, vomiting, and bowel obstruction and infarction caused by inspissated charcoal
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when is charcoal not recommended
ingested corrosives because it will obscure endoscopy
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what method is preferred for life-threatening poisons that cannot be treated with other method
gastric lavage
104
how is gastric lavage performed?
performed by sequentially administering and aspirating 5 ml of fluid per kilogram of body weight through a no.40 French orogastric tube (no. 28 for children)
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preferred solute used in gastric lavage in infants
normal saline and tap water
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the positon of px when doing gastric lavage to prevent aspiration
trendelenburg and left lateral decubitus
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lavage absoprtion within 5 mins, 30 mins and 60 mins of ingestion
decreases as time lengthens
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common complication of gastric lavage
aspiration
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serious complication of gastric lavage
esophageal and gastric perforation and tube misplacement
110
contraindicated in gastric lavage
corrosive
petroleum distillate ingestions because the risk of gastroesophageal perforation and aspiration pneumonitis
compromised airway
risk of hemorrhage or perforation due to esophageal or gastric pathology
recent surgery
px who refuse
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emetogenic agent that is once used in decontamination but no longer used in decontamination
syrup of ipecac
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chronic use of ipecac complications
electrolyte and fluid abnormalities, cardiac toxicity, and myopathy
113
another method for gastric decontamination that is performed by administering bowel cleansing solution that contains electrolytes and polyethylene glycol
whole bowel irrigation
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whole bowel irrigation is appropriate in px with
ingested foreign bodies
packets of ilicit drugs
and heavy metals
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salts given together with charcoals to promote the rectal evacuation of gastrointestinal contents
cathartics
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side effects of cathartics
abdominal pain
nausea
occasional vomitting
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complications of repeated doses of cathartics
severe electrolytes disturbances and excessive diarrhea
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contraindications of cathartics
ingested corrosives and with preexisting diarrhea
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when is dilution recommended
only after the ingestion of corrosives
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technique used in rare situations such as ingestions of potentially toxic foreign bodies
endoscopic or surgical removal
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initial treatment for for topical exposures
immediate copious flushing with water and saline
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preferred for eye irrigation
saline
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treatment for inhlational exposures
supplemental oxygen or fresh air
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treatment for inhlational exposures
supplemental oxygen or fresh air
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treatment for dermal decontamination
triple wash
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removal of liquids in cavities such as vagina and rectum
irrigation
126
when is multiple-dose of charcoal therapy considered
ingestion of theophyline, phenobarbital, carbamazepine, dapsone and quinine
127
complications of multiple-dose charcoal therapy
intestinal obstructions, pseudo-obstruction and nonoccluisive intestinal infarction in px with decreased gastric motility
128
how urinary alkalinization works
ion trapping via alteration of urine ph may prevent the renal absorption of poisons that undergo excretion by glomerular filtration and active tubular secretion
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what ions are trapped in the membrane
acidic are ionized and trapped in alkaline urine whereas basic become ionized and trapped in acid urine
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urine alkalinization urine ph
ph >7.5 and urine output of 3-6 ml of body weight per hour by the addition of sodium bicarbonate to an IV solution
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contraindication of urinary alkalinization
congestive heart failure, renal failure and cerebral edema
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agents most amenable to enhance elimination bu dialysis
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low molecular mass <500
high water solubility
low protein binding
small volumes of distirbutio (<1l)
prolonged elimination (long half life)
high dialysis clearance relative to total body clearance
```
133
when is dialysis considered
severe poisoning due to carbamazepine, ethylene glycol, isoprophyl alcohol, lithium, methanol, theophyline, salicylates and valproate
134
candidates for extracorporeal removal
px with severe toxicity whose condition deteriorates despite the aggressive supportive therapy, those with potentially prolonged irreversible or fatal toxicity, those with dangerous blood level of toxins, those who lack capability for self detoxification because of liver or renal failure and those with serious underlying illness or complication that will adversely affect recovery
135
how do antidotes work
counteract the effect of poisons by neutralizing them or by antagonizing their physiologic effect by activation of opposing nervous system activity, provision of competitive metabolic or receptor substance
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how to prevent re-exposure
limit their access to poisions
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fundamentals of supportive care in poisoning management
```
airway protection
oxygenation/ventilatiom
treatment of arrythmias
hemodynamic support
treatment of seizures
correction of temperature and abnormalities
correction of metabolic derangement
prevention of secondary complications
```
138
fundamentals in prevention of further poisoning absoprtion
gastrointestinal decontamination such as gastric lavage, activated charcoal, whole bowel irrigation,dilution and endoscopic surgical removal and decontamination of other sites such as eye, skin and body decontamination
139
fundamentals in enhancement of poison elimination
multiple dose activated charcoal
alteration of urine ph
chelation
extracorpeal removal
140
causes of stimulated physiologic condition
sympathetic such as sympathomimetics, ergot alkaloids, methylxanthines, monoamide oxidase inhibitors
anticholinergics such as antihistamines, antipsychotics and belladona alkaloids, cyclic depressants and mushroom and plants
141
examples of sympathomimetics
a1 adrenergic agonist and b2 adrenergic agonist
142
mechanism of action of sympathomimetics
stimulation of central and peripheral sympathetic receptor directly or indirectly (release and inhibit release of norepi and dopamine)
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mechanism of action of sympathomimetics
stimulation of central and peripheral sympathetic receptor directly or indirectly (release and inhibit release of norepi and dopamine)
144
clinical features of sympathomimetics
a1- reflex bradycardia
| b- hypotension and hypokalemia
145
treatmen of sympathomimetics
phentolamine-severe hypertension
| labetalol-hypotension and tacycardia
146
examples of ergot alkaloids
ergotamine
methysergide
bromocriptine
pergolide
147
mechanism of action of ergot alkaloids
stimulation and inhibition of serotonergic and a adrenergic receptors
simulation of dopamine receptors
148
clinical features of ergot alkaloids
formication and vasospasm with limb, myocardial and cerebral ischemia to gangrene and involuntary movements
149
treatment for ergot alkaloids
nitroprusside or nitroglycerine for vasopasm
prazosin, captopril- limb ischemia
dopamine for movement disorders
150
examples of methyxanthines
caffeine and theophylline
151
mechanism of action of methylxanthines
inhibition of adenosine synthesis and adenosine receptor antagonism
stimulation of epi and norepi release
inhibition of phosphodiesterase-increased intracellular cyclic adenosine and guanosine monophosphate
152
clinical features of methylxanthines
pronounced gastrointestinal symptoms
| toxicity occur at lower drug level in chronic than in acute
153
treatment of methylxanthines
propranolol for tacycardia with hypotension
| beta blocker for supraventricular or ventricular tacycardia
154
indications for hemoperfusion and hemodialysis
unstable vital signs
seizures
theophylline level of 80-100 after acute overdose and 40-60 with chronic exposure
155
example of monoamide oxidase inhibitors
phenelzine
tranycypromine
selegiline
156
mechanism of action of monoamine oxidase inhibitors
inhibition of monoamide oxidase resulting in impaired metabolism of endogenous catecholamines and exogenous sympathomimetic agent s
157
clinical feature of monoamine oxidase inhibitors
delayed and slowly progressive
| terminal hypotension and bradycardia in severe cases
158
treatment of monoamine oxidase inhibitors
short acting agents such as nitroprusside and esmolol for severe hypotension and tacycardaia
direct acting sympathomimetic: norepi and epi for hypotension and bradycardia
159
examples of anticholinergic agents
```
antihistamines
antipsychotics
belladonna alkaloids
cyclic antidepressants
mushrooms and plant s
```
160
examples of anti-histamines
diphenydramine
doxylamine
pyrilamine
161
mechanism of action of antihistamines
inhibition of central and postganglionic parasympathetic muscarinic cholinergic receptors
162
clinical features of anti-histamines
```
dry skin
mucous membranes
decreased bowel movements
flushing
urinary retention
myoclonus
picking activity
```
163
treatment of antihistamines
physostigmine for delirium and neuromuscular hyperactivity
164
examples of antipyschotics
chlorpromazine
olanzapine
quetiapine
thioridazine
165
mechanism of action of antipsychotics
inhibition of alpha adrenergic dopaminergic histaminergic muscarinic and serotonegic receptors
inhibit sodium, pottasium and calcium channles
166
clinical features of antipsychotics
miosis
anticholinergic effects
extrapyramidal effects
tachycardia
167
treatment for antipsychotics
sodium bicarbonate for ventricular tachydysrhymias
| magnesium, isoproterenol in torsades des pointes
168
examples of belladonna alkaloids
atropine
hyoscyamine
scopolamine
169
mechanism of action of belladonna alkaloids
inhibition of central and pots-ganglionic parasympathetic muscarinic cholinergic receptors
170
clinical features of belladonna alkaloids
```
dry skin
mucous membrane
decreased bowel sounds
flushing
urinary retention
myoclonus
picking activity
```
171
treatment for belladonna alkaloids
physostigmine
172
examples of cyclic depressants
amitriptyline
dexopine
imipramine
173
mechanism of action of cyclic depressants
inhibition of alpha adrenergic dopaminergic , histaminergic and muscaranic and serotonergic receptors
inhibition of nore and epi
inhibition of serotonin reuptake
174
clinical features of cyclic antidepressants
```
seizures
tachycardia
cardiac
conduction delays
anticholinergic toxidrome
```
175
treatment of cyclic depressants
hypertronic sodium bicarbonate
