Tox Flashcards
Toxins most frequently dialyzed
ASA, Li, methanol, ethylene glycol, theophylline
drugs that are dialyzable:
blist med
barbituates, lithium, inh/iron, salycilates, thophylline, methanol, ethylene glycol, depakoate
Multi dose activated charcoal
GI dialysis
For drugs w/ large volume of distribution
Theophylline, phenobarbital, carbamazepine
-Quinine, salicylates, sustained release formulas
Serum osm
- Should be done in the setting of persistent acidosis
- Useful if elevated
- Difference between measured osm and calculated osm >10 is always significant.
- Abnormal osmolal gap does NOT rule out toxic alcohol ingestion
Methanol metabolism
MeOH -(via ADH)-> formaldehyde -Aldehyde dehydrogenase)-> formic acid -(Folate cofactor)-> CO2 + H2O
causes blindness and
basal ganglia necrosis -> parkinsonian
Physostigmine
- anticholinergic antidote
- indications: central & peripheral effects
- contraindications: h/o severe bronchospasm, low heart rate, abnormal cardiac conduction
Indication for HD in toxic alcohols
presence of toxic metabolites of ethylene glycol and methanol
drugs assoc w/ hypoglycemia
Tylenol Salicylates Insulin Alcohol Oral hypoglycemics Check a glucose on all pts w/ AMS!!
indications for activated charcoal
if ingestion occurs w/in 1 hour & a rapid deterioration is expected (eg TCAs), or if a small decrease in toxin may be critical
1-2g/kg
optimal charcoal:toxin ratio is 10:1 by weight
contraindications to charcoal?
- Contraindicated in ingestion of HYDROCARBONS, b/c toxicity from gastric absorption not a major concern
- Caustics, acids or alkalis - b/c tox from burns
- Trivial ingestions
indications for urine alkalinization in overdose
salicylates, phenobarb, INH
target urine pH of 7-8
Replace K to alkalinize urine - needed for HCO3 to be excreted
NO urine acidifications or forced diuresis - don’t work!
indications for HD in overdose
water soluable, small Vd
low protein binding
low molecular weight
eg: salicylates, toxic alcohols, Li, theophylline, phenobarbital
antidote for tylenol
NAC
antidote for arsenic
NAD, DMS
antidote for ASA
alkaline diuresis w/ IV NaHCO3
hyperventilate if intubated to keep alkalotic
antidote for BB
glucagon
antidote for barbituate
alkaline diuresis, HD
antidote for CCB
Ca, glucacon, glucose/insulin
antidote for carbamate
atropine
antidote for CO
100% O2, hyperbaric O2
antidote for warfarin
FFP, Vit K
antidote for cyanide
sodium nitrite, sodium thiosulfate or
hydroxycobalamin
antidote for digitalis
digibind, fab fragments
antidote for ethylene glycol
EtOH, dialysis, 4-MP
antidote for heparin
protamine
antidote for hydrofluoric acid
Ca, Mg
antidote for Fe
deferoxamine
antidote for INH
Vit B6 (pyridoxine)
antidote for Pb
BAL, DMS, EDTA
antidote for MERCURY
BAL, DMS
antidote for methemoglobin
methylene blue
antidote for methanol
EtOH, dialysis, 4MP
antidote for nitrites
methylene blue
antidote for opiates
naloxone
antidote for organophosphates
atropine, 2-PAM
antidote for oral hypoglycemic agents
glucose, glucagon, octreotide
antidote for TCA
Sodium bicarbonate
If seizing give benzodiazepine
causes of elevated anion gap metabolic acidosis
Ketones Uremia Lactic acid Toxic alcohols Salycilates
gastric lavage
only useful if <1H on in large overdoses where chargcoal wont work
c/i: caustics, hydrocarbons, AMS w/o airway control, pt refusal
whole bowel irrigation
golytely to prevent intestinal absomrption
dose 2L/hr per NGT until clear rectal effluent
heavy metals, drug packers, sustained-release meds
c/i: gi bleed, bowel obstruction/perf
gi decon
decontaminate before symptoms appear
Rumack-Matthew nomogram
acute Tylenol only
the likelihood of hepatic toxicity given an acetaminaophen level and time
Below nomogram line, hepatotoxicity unlikely to occur
Above nomogram line, hepatotoxicity is probable and NAC is inidicated
bt the two nomogram lines hepatotox is possible and clinical judgement is required
150–200
4 hour post ingestion level is the most important and accurate initial point for the nomogram line
NAC
repletes glutathione stores
oral or iv forms available
virtually 100% protection if given w/in 8 hours of ingestion
tylenol metabolization
Tylenol metabolized in liver to sulfate and glucuronide conjugates
as these pathways become saturated, more APAP gets shunted towards the P450 pathway resulting in increasedd NAPQI
detox of NAPQI depletes glutathione stores
low glutathione stores leads to nonspecific action of NAPQI and damages cell
NAC repletes glutathione stores thus preventing hepatotoxic effects of NAPQI
indications for HD in ASA overdose
AMS, cerebral/pulmonary edema, renal failure
salicylate >100 mg/dL in acute overdose
where can ethylene glycol be found
antifreeze
where can methanol be found
wood alcohol
windshield wiper fluid
toxic alcohols
EtOH, isopropanol, MeOH, EtOH
all cause an abnormal osmolar gap
all are metabolized by ADH
metabolism of isopropanol does not cause an elevated anion gap
toxic metabolites of ethylene glycol
glyoxylic acid
oxalic acid
indications for digibind
1 rhythm/conduction disturbance
2 K >5 mEq/dL
3 serum dig >10-15 in an acute ingestion 6 hours post ingestion
or >4 in a chronic ingestion
4 acute dig ingestion of >10 mg (4 mg in a child)
5 empirically for undiagnosed bradycardia (clinical judgement)
empiric tx for acute overdose is 10 vials (adult or child)
empiric tx for chronic overdose is 5 vials in adult
Sulfonylurea poisoning
Dextrose then octreotide
Octreotide a synthetic somatostatin analog, antagonizes release of insulin
Isopropanol
metabolized to acetone by ADH (alcohol dehydrogenase)
causes ketosis w/o acidosis
minimal toxicity
Glucagon
Insulin antagonist
Relaxes smooth muscle of gi tract
Clonidine in overdose
Centrally acting alpha 2 agonist.
Expressed level of consciousness
Respiratory depression
Mitosis
May closely mimic opioid overdose
EKG changes in TCA OD
QRS widening
Terminal R in aVR
S in lead I
GHB OD
Intermittent bouts of agitation with quick return to coma
Rapid full return to consciousness from comatose state
Linezolid
Has MAOI properties
Anticholinergic plants
Jimsonweed
Effexor in overdose
SNRI
Has Na channel blocking properties
Significant overdose can present with
QRS prolongation
Seizures
Presentation and tx similar to TCA overdose
HF burn
Where do u find it?
Silver cleaner
What does burn look like?
Mgmt?
Indications for 4MP in toxic alcohols
ethylene glycol and methanol ingestions
