Decon, enhancing elimination, antidotes Flashcards
Hemodialysis effectively removes valproic acid at toxic, but not therapeutic, concentrations because what is true at toxic concentrations?
A.A greater proportion is not protein bound
B.Intracellular binding falls
C.It has a lower volume of distribution
D.It can be absorbed to dialysis membranes
E.It is dissociated into the more diffusible nonionic form
A. At higher toxic concentrations, a higher proportion of the drug is free in the plasma and more available for removal by hemodialysis or hemofiltration. At therapeutic concentrations, a large proportion is protein bound, but as the concentrations rise, the protein-binding sites are saturated and free valproic acid concentrations increase.
With regards to succimer, which statement is false?
A.It has a sulfur odor and flatulence can be a fire hazard.
B.It mobilizes lead from soft tissues and even bone when combined with EDTA
C.It can facilitate absorption of lead from the gut
D.The injections are very painful and those with peanut allergies cannot receive this therapy.
E.Patients who have lead in their gut must have it removed prior to starting chelation.
D. Painful injections and peanut allergies are true for BAL – British Antilewsite. Succimer is given orally.
Besides benzos, what is the treatment for seizures from the following substances?
A.Carbamates/OPs _____________________
B.Hypoglycemics _______________________
C.Mushrooms (gyromitra) _________________
D.Anticholinergics _______________________
E.Isoniazid ______________________________
- Carbamates and organophosphates – atropine and 2 PAM
- Hypoglycemics – dextrose and octreotide
- Gyromitra mushrooms (monomethylhydrazine) – pyridoxine
- Anticholinergics – Physostigmine
- Isoniazid – pyridoxine
In what situations would decontamination with water not be recommended?
Water should not be used for any reactive alkali metals that form strong bases in water, like sodium, potassium, lithium, cesium, rubidium, dusts of pure magnesium, sulfur, strontium, titanium, uranium, yttrium, zinc, zirconium.
With the following treatment options, describe instances where you would not give this as a therapy.
- Physostigmine
- Beta blockers
- Calcium
- Class 1A, 1C, and III antiarrhythmics
- Methylene blue
- BAL
- HBO – hyperbaric oxygen
- Sodium nitrite
- Physostigmine – don’t give for wheezing/reactive airway disease, use of succinylcholine for intubation, TCAs on board, QRS >100, AV block/bradycardia
- Beta blockers – never use in sympathomimetic toxidrome presentations because the selective beta blockade may result in unopposed alpha stimulation
- Calcium – never give in digoxin toxicity with hyperkalemia – can worsen bradycardia and arrhythmias
- Class 1A, 1C and III antiarrhythmics – can worsen sodium channel blockade
- Methylene Blue – not for use with those with G6PD deficiency
- BAL – not for use for those with peanut allergies
- HBO – not for use for those with pneumothorax
- Sodium nitrite is not indicated for cyanide toxicity with smoke inhalation
Which would be most completely absorbed by 50 grams of AC?
A.50 tablets of cetirizine
B.50 SR tablets of theophylline 300mg
C.50 tablets of lithium 300mg
D.100ml of 40% alcohol
E.100 tablets of ferric chloride
Answer: A. Antihistamines are well absorbed to AC. ETOH is poorly absorbed by AC. Lithium and iron ions are too small to bind with AC. Theophylline would be better managed with MDAC doses, especially with this ER preparation.
In which situation should AC be avoided?
A.ASA overdose with a defiant attitude
B.An alert child who ate a mushroom while foraging with the parents
C.A child who ingested some campho-phenique
D.An accidental quadruple dose of ER sotalol
E.A child who ingested mother’s carbamazapine
Answer C: Possible CNS deterioration and/or seizures from a camphor product should definitely be a good reason to avoid activated charcoal. The other reasons would be good reasons.
Seven reasons for MDAC
- Drugs with significant recirculation
- Prolonged ½ life
- Small Vd
- Limited protein binding
- Sustained release and enteric coated forms
- Onset of organ failure where elimination is thwarted (such as bezoars)
- Drugs with increased transport across cell membranes
Six Drugs with Enterohepatic Recirculation
- Carbamazapine
- Digitoxin
- Colchicine
- Dapsone
- Thallium
- Valproic acid
Hemodialysis would be expected to be most useful for enhancing the elimination of a XB (xenobiotic) with which characteristic?
A.Low degree of protein binding
B.High lipid solubility
C.High molecular weight
D.High volume of distribution (Vd)
E.Minimally ionized at physiological pH
Answer A: Low degree of protein binding. Hemodialysis removes solutes by diffusion from blood – dialysate across a semipermeable membrane. Molecules bound to plasma proteins, which in general, are too large to cross the membrane, will not be dialyzed. Molecules with a large Vd are bound to proteins or tissues or are soluable in non aqueous phases, such as lipids, and are not diffusible. Diffusion is also limited with XB with high molecular weight. Molecular charge does not directly affect the success of hemodialysis.
Antidote for Cyanide
1.Hydroxocobalamin, sodium nitrate/thiosulfate
Antidote for Iron
Deferoxamine
Antidote for Isoniazid
Pyridoxine
Antidote for Methemoglobinemia
methylene blue
Antidote for organophosphate poisoning
Atropine and 2-PAM
Antidote for Sulfonylureas
Octreotide
Antidote for Valproic acid
L-carnitine
Antidote for methotrexate toxicity
Folinic Acid or Leucovorin
Antidote for Thallium
Prussian Blue
antidote for heparin
protamine sulfate
Antidote for Coumadin
Vitamin K, FFP
Digibind binds specifically to the________________
digoxin or cardiac glycosides
Methylene blue increases the ability ______________________
to detoxify methemoglobin
Narcan antagonizes the effect ________
of opiates
Calcium causes ionic binding to produce insoluable salts to _______
hydrofluoric acid
Lipids cause non-specific lipid binding to ______________
to calcium and beta blockers
Which XB has rebound serum concentrations after hemodialysis as a result of equilibrium from intracellular stores and often result in a need for repeat dialysis?
A )Alcohol B )Ethylene glycol C) Lithium D) ASA E) Theophylline
Answer C: Lithium’s removal by hemodialysis allows rapid equilibrium from intracellular to extracellular volumes. Increases in serum concentrations may rebound within hours after cessation of dialysis which may necessitate repeat therapy.
Which characteristic of APAP makes hemoperfusion a clinically undesirable treatment for overdose?
A) Efficacy of N-AC B) High renal clearance C) High Vd D) Lack of major morbidity E) Poor intestinal absorption
Answer A. APAP has a low molecular weight. An oral dose is almost all absorbed, has low Vd with only 25% protein bound. N-AC is very efficacious and thus many times dialysis is not a necessary consideration. For lethal APAP levels and metabolic acidosis, dialysis is certainly indicated.
In controlled studies, which modality has been demonstrated to improve survival in poisoned patients? A) MDAC B) Orogastric lavage C) Osmotic diuretics D) Single dose AC E) Sodium polystyrene
Answer A: MDAC was demonstrated to improve survival.
MDAC does not increase the clearance of which XB? A) Carbamazapine B) Doxepin C) Nortriptyline D) Phenobarbital E) Phenytoin
Answer B: MDAC increases clearance of all except doxepin.
Alkalinization of the urine by administration of Na HCO3 is likely to enhance the elimination of XB with what characteristic? A) Amphoteric B) Strong acid C) Strong base D) Weak acid E) Weak base
Answer D: weak acids (ASA) dissociate in more alkaline urine. Weak bases (PCP) dissociate in more acidic urine.
Which is true of Crofab?
A) It is an equine-derived whole IgG antivenom
B) It prevents tissue necrosis
C) It limits progression of swelling
D) It does not produce hypersensitivity reactions
E) It is indicated in MGMT of all North American elapid envenomations
Answer C. Crofab is an ovine-derived fab immunoglobin. It is less immunogenic that previous Wyeth, but allergic reactions can still occur. They will not treat envenomations from elapids – only North American crotalid envenomations
It can halt the progression of swelling but is not expected to reverse tissue necrosis.
Which statement about neutralization following caustic ingestions is correct?
A) Neutralization has no role in the MGMT in any caustic ingestion.
B) Neutralization requires a small volume of neutralizing agent to attain physiological pH
C) Neutralization should be considered following the ingestion of acids known to cause severe systemic toxicity
D) Neutralization therapy has not shown to worsen tissue damage via generation of exothermic reactions
E) Neutralization therapy with orange juice has proven to be helpful in prevention of significant injury following ingestion of sodium hydroxide in humans.
Answer A: There is no data to support the routine use of neutralization. This can be potentially harmful.
When comparing ETOH with Antizol/fomipizole, which aspect of treatment is similar? A) Ease of administration B) Side effect profile C) Efficacies D) Acquisition cost E) Monitoring required
Answer C. Studies demonstrate no pharmacologic advantage of Antizol over ETOH, assuming both are dosed appropriately. ETOH is more difficult to administer and requires frequent BAL to ensure adequacy of therapy. It also has significant side effects. The only advantage to ETOH is that it can be given orally and the acquisition cost of oral ETOH is relatively cheap. IV ETOH is no longer commercially available and must be prepared, so there would be a delayed amount of time to administration. Antizol 1 gram IV costs about $1,233.20!!
Regarding dilutional therapy following caustic ingestions, which is correct?
A) Milk should be encouraged with patients with nausea, drooling or stridor
B) Dilutional therapy provides minimal efficacy unless given within minutes of TOI
C) Due to its greater tissue contact time, delayed dilutional therapy may be grater value in liquid caustic ingestions
D) A child who refuses to swallow should be allowed their beverage of choice
E) Studies of dilutional therapy with milk have consistently shown a benefit following alkaline esophageal injuries
Answer C. Dilutional therapy does not increase damage although efficacy was greatly diminished as length of time following caustic exposure increases.
Which medication is metabolized by plasma cholinesterase and may have enhanced effect toxicity in cholinesterase-inhibited patients? A) Atropine B) Lidocaine C) Succinylcholine D) Meperidine E) Diazpeam
Answer C. Succinylcholine is metabolized via pseudocholinesterase (plasma choinesterease) and will. Have a prolonged duration of action in an organophosphate toxic patient.
When zinc explodes, how is dermal decontamination accomplished? A) Tepid water B) Normal saline C) Mineral oil D) Hydrostatic air E) Betadine
Answer C. After a zinc explosion occurs, dermal decontamination is best accomplished by removing metallic particles with forceps and then applying mineral oil. The mineral oil is used to prevent contact of zinc with the moisture in the air. Water should not be used as it will cause zinc to further ignite.
Which is an adverse effect of nitrite administration? A) Rhabdomyolysis B) Hair loss C) Diminished PO2 D) Hypotension E) Red flushed skin
Answer D. Hypotension is a common result of nitrates/nitrites mediated vasodilation.
Excessive methemoglobinemia is another adverse effect that would result in cyanosis but not a decrease in the PO2.
Treatment for inhalants includes which one?
A) HBO with n-hexane metabolite 2,5 hexanedione
B) Fomepizole after inhalation of carburetor cleaner
C) NAC after inhalation of toluene
D) Methylene blue following inhalation of “whippets”
E) Vitamin E following kerosene abuse
Answer B. Fomepizole can be used for the treatment of intentionally inhaled methanol-containing carburetor cleaners.
HBO would be appropriate with a methylene chloride inhalation (since it is metabolized into CO)
NAC would be helpful following carbon tetrachloride inhalation
Methylene blue would be helpful following volatile amyl nitrites (not nitrous oxide)
What is the most common clinical finding in organophosphate toxicity that is not effectively treated with Atropine? A) Bronchorrhea B) Miosis C) Muscle weakness D) Diarrhea E) Bronchoconstriction/spasm
Answer C. Atropine will treat all except muscle weakness as the neuromuscular junction is a nicotinic cholinergic receptor.
Nebulized 2% Na HCO3 may be useful in patients exposed to which pulmonary irritant? A) Nitrogen dioxide B) Chloracetophenone C) Chloride D) Ammonia E) Ozone
Answer C. Nebulized Na HCO3 provides relief from pain and cough in patients exposed to chlorine gas. This probably results from neutralization of HCL acid that forms when chlorine gas dissolves in water from the oropharyngeal mucosa to the alveoli.
Doxycycline would be the least effective in treating which biological agent? A) Anthrax B) Brucellosis C) Plague D) Smallpox E) Tularemia
Answer D. Smallpox is the only virus among them. Even if you had no idea what the answer was – try to see what the common theme is (bacterial vs viral) and then you have your answer.
Which is true regarding reactivity of hazmat with water?
A) This is not a clinical concern
B) Only a concern if hazmat on the victim is visible
C) Flushing with water must not be used
D) Dry wiping should be used initially
E) Irrigation with water is preferred to water
Answer D. Water reactivity is a worksite safety concern with explosions/fires when bulk amounts of certain chemicals come into contact with water.
Removal of as much chemical as possible prior to flushing with water seems reasonable. Flushing action of water is very important separating hazmat from the skin or mucous membranes.
High doses of atropine, sometimes in excess of 1000mg, may be required to effectively treat the toxicity caused by what? A) Parathion B) Phosgene C) Sarin D) Soman E) Tabun
Answer A. Although nerve agents are extremely potent, acute treatment requires less atropine than for victims poisoned to a similar degree with organophosphate insecticides. The total dose of atropine required in nerve agent victims typically does not exceed 12-20 mg with in the first 24 hrs.
