Updated: 5/5/2019

Poisons and Treatments

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Overview
 
Treatment Poison(s) Notes
Deferoxamine  Iron
Used for aluminum poisoning in renal failure
Used in repeat transfusions that can cause iron overload (thalassemia)
Used in iron overdose
Deferasirox
Prussian blue Cesium
Thallium
Used in the case of a radioactive incident
Penicillamine Copper (Wilson's disease)
Water-soluble form of penicillin
Avoid in patients who have penicillin allergy
Weak association with improve outcomes in scleroderma
EDTA Lead
Can chelate and deplete calcium ions
Only needed in moderate to severe lead poisoning
Dimercaprol (BAL) Arsenic
Lead
Mercury
Used in conjunction with EDTA for lead poisoning
Succimer Arsenic
Lead
Mercury
Chelation therapy more commonly used in children
N-acetylcysteine  Acetaminophen
Best if given with 8-10 hours
Also a mucolytic
Best next step in management if you suspect acetaminophen intoxication yet have no lab results (it is a benign treatment)
Sodium bicarbonate Salicylates 
Tricyclic antidepressants (TCA)
First sign of OD is hyperventilation and respiratory alkalosis
Do not give with physostigmine
First do an EKG, if wide QRS (in TCA overdose) then try sodium bicarbonate
Deprotonation of drugs causes improved urinary excretion
Potassium iodide Radioactive iodine (I-131)
Given to prevent the uptake of I-131
Can also be used in thyroid storm as iodine initially decreases thyroid hormone production
Ammonium chloride (NH4Cl, acidic) Amphetamines (basic)
Eliminates amphetamines by acidifying urine which results in a charged amphetamine molecule which is excreted

Atropine

Anticholinesterases
Organophosphates
Sarin (nerve gas)
Atropine blocks Ach receptors decreasing the effect of these drugs
Pralidoxime, if given in a timely manner, regenerates acetylcholinesterase reversing the initial pathology
Pralidoxime 
Physostigmine Antimuscarinic
Anticholinergic agents
Do not give if patient may have TCA OD as it may lead to heart block or asystole
Tertiary amine that can cross the BBB and reverse CNS symptoms of atropine
Naloxone/naltrexone Opioids
Precipitates withdrawal symptoms in chronic opioid users
Not indicated in neonates who may be withdrawing
Indicated particularly in adult patients who have respiratory depression
Naltrexone decreases alcohol cravings
Flumazenil  Benzodiazepines
May cause seizures in addicted benzodiazepine users
Not routinely used, better to let the patient "sleep off" their benzodiazepine overdose
Ensure patient maintains respiratory effort and airway
Ethanol IV infusion Antifreeze (ethylene glycol)
Methanol
Think antifreeze when ingested substance is said to be sweet and individual appears "drunk without the typical smell of alcohol"
Fomepizole
Glucagon β-blockers  
IM glucagon is best initial therapy
β-blockers (propranolol, esmolol) Theophylline
OD symptoms are due to β2 activation: hypotension, tachycardia, hypokalemia, hyperglycemia

Digitalis antibody, lidocaine, Mg2+

Digitalis
GI disturbance and visual halos classic in overdose
Amyl and sodium nitrite Cyanide 
Cyanide found in rodenticides "gopher goitter", released in burning of plastics and wool, and plants such as cassava
Cyanide binds Fe3+ of cytochrome c in the electron transport chain and blocks cellular respiration
Nitrites generate methemoglobin, which can save the ETC by binding up the cyanide
Sodium thiosulfate
Hydroxycobalamin
Methylene blue Methemoglobin
Iron in the heme molecule is Fe3+ which cannot bind oxygen until it is reduced to Fe2+ by treatment
Vitamin C
100% O2 (consider hyperbaric O2 Carbon monoxide (CO)
CO binds with much greater affinity than O2
Aminocaproic acid  tPA
Streptokinase
-
Vitamin K Warfarin
Bridge with heparin
If patient suddenly has increase in PT/PTT look for other medications that are P450 inhibitors
Plasma infusion
Protamine Heparin 
Protamine is a highly positively charged peptide which strongly binds to the negatively charged heparin
Antivenin Rattlesnake bite
 -

 

Iron Poisoning
  • Most deaths due to iron poisoning (ingestion of iron tablets) occur in children between 12 - 24 months of age
  • Symptoms occur within 30 min to several hours
    • abdominal pain, diarrhea, vomiting
    • cyanosis, drowsiness, hyperventilation resulting from acidosis
  • Death can result in six hours, but an apparent recovery may happen from 6 - 12 hours with death ensuing in the next 12 hours
  • If not treated early, damage to the stomach can lead to pyloric stenosis or gastric scarring
  • Early treatment with deferoxamine can reduce mortality significantly from 45% to 1%
  • Mechanism of action of iron related damage
    • iron overdose results in the peroxidation of membrane lipids leading to cell death
    • the Fenton reaction produces dangerous free radicals
Methanol and Ethylene Glycol Toxicity
  • Each are competitive substrates for alcohol dehydrogenase (ADH) 
  • Methanol
    • metabolized by ADH to formaldehyde followed by aldehyde dehydrogenase to form formic acid which is toxic to the optic nerve
      • early toxicity of formic acid is metabolic acidosis by formic acid itself
      • formic acid also binds to cytochrome oxidase blocking oxidative phosphorylation
      • resulting in lactic acidosis which is the latter and leading cause of the metabolic acidosis
    • signs and symptoms appear within 12 - 24 hours after ingestion
      • CNS depression
        • methanol acts similarly as ethanol as a CNS depressant
      • metabolic acidosis
      • visual changes
        • blindness occurs with as little as 30 mL and death at 100 mL ingestion
  • Ethylene glycol
    • colorless, odorless, sweet-tasting liquid
    • toxicity derives from the hepatic oxidation of ethylene glycol to oxalic acid
      • degraded by same pathway as methanol
        • the glycolic acid produced by aldehyde dehydrogenase is converted in oxalic acid
      • oxalic acid binds calcium and forms calcium oxalate crystals that damage the heart, brain, lungs, kidneys
    • signs and symptoms develop in stages after ingestion
      • first stage: 0.5 - 12 hours
        • stronger inebriant than methanol and ethanol causing mild depression of CNS resulting in seizures and coma
        • patients appear "drunk without smelling like alcohol"
        • within 4 - 12 hours, calcium oxalate crystals deposit in the brain causing CNS toxicity, cerebral edema, meningismus (nuchal rigidity, photophobia, headache without infection or inflammation)
        • hypocalcemia occurs due to binding of calcium by oxalic acid and can cause prolonged QT, arrhythmias, myocardial depression
      • second stage: 12 - 24 hours
        • tachypnea occurs to offset the metabolic acidosis due to the toxic metabolites produced
        • multiorgan failure (CHF, lung injury, myositis) due to widespread crystal deposition
        • NOTE: most deaths occur in the second stage
      • third stage: 24 - 72 hours
        • acute anuric renal failure from crystal deposition but full recovery occurs within weeks to months
  • Treatment
    • IV ethanol: competitive substrate for ADH and has greater affinity for ADH than methanol and ethylene glycol
    • fomepizole: inhibits ADH preventing production of toxic metabolites
Ingested seafood toxins
  • Tetrodotoxin
    • Highly potent toxin that binds to fast voltage-gated Na+ channels, preventing depolarization
    • Presents with nausea, diarrhea, paresthesias, weakness, dizziness, and loss of reflexes
 
 

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Questions (16)
Lab Values
Blood, Plasma, Serum Reference Range
ALT 8-20 U/L
Amylase, serum 25-125 U/L
AST 8-20 U/L
Bilirubin, serum (adult) Total // Direct 0.1-1.0 mg/dL // 0.0-0.3 mg/dL
Calcium, serum (Ca2+) 8.4-10.2 mg/dL
Cholesterol, serum Rec: < 200 mg/dL
Cortisol, serum 0800 h: 5-23 μg/dL //1600 h:
3-15 μg/dL
2000 h: ≤ 50% of 0800 h
Creatine kinase, serum Male: 25-90 U/L
Female: 10-70 U/L
Creatinine, serum 0.6-1.2 mg/dL
Electrolytes, serum  
Sodium (Na+) 136-145 mEq/L
Chloride (Cl-) 95-105 mEq/L
Potassium (K+) 3.5-5.0 mEq/L
Bicarbonate (HCO3-) 22-28 mEq/L
Magnesium (Mg2+) 1.5-2.0 mEq/L
Estriol, total, serum (in pregnancy)  
24-28 wks // 32-36 wks 30-170 ng/mL // 60-280 ng/mL
28-32 wk // 36-40 wks 40-220 ng/mL // 80-350 ng/mL
Ferritin, serum Male: 15-200 ng/mL
Female: 12-150 ng/mL
Follicle-stimulating hormone, serum/plasma Male: 4-25 mIU/mL
Female: premenopause: 4-30 mIU/mL
midcycle peak: 10-90 mIU/mL
postmenopause: 40-250
pH 7.35-7.45
PCO2 33-45 mmHg
PO2 75-105 mmHg
Glucose, serum Fasting: 70-110 mg/dL
2-h postprandial:<120 mg/dL
Growth hormone - arginine stimulation Fasting: <5 ng/mL
Provocative stimuli: > 7ng/mL
Immunoglobulins, serum  
IgA 76-390 mg/dL
IgE 0-380 IU/mL
IgG 650-1500 mg/dL
IgM 40-345 mg/dL
Iron 50-170 μg/dL
Lactate dehydrogenase, serum 45-90 U/L
Luteinizing hormone, serum/plasma Male: 6-23 mIU/mL
Female: follicular phase: 5-30 mIU/mL
midcycle: 75-150 mIU/mL
postmenopause 30-200 mIU/mL
Osmolality, serum 275-295 mOsmol/kd H2O
Parathyroid hormone, serume, N-terminal 230-630 pg/mL
Phosphatase (alkaline), serum (p-NPP at 30° C) 20-70 U/L
Phosphorus (inorganic), serum 3.0-4.5 mg/dL
Prolactin, serum (hPRL) < 20 ng/mL
Proteins, serum  
Total (recumbent) 6.0-7.8 g/dL
Albumin 3.5-5.5 g/dL
Globulin 2.3-3.5 g/dL
Thyroid-stimulating hormone, serum or plasma .5-5.0 μU/mL
Thyroidal iodine (123I) uptake 8%-30% of administered dose/24h
Thyroxine (T4), serum 5-12 μg/dL
Triglycerides, serum 35-160 mg/dL
Triiodothyronine (T3), serum (RIA) 115-190 ng/dL
Triiodothyronine (T3) resin uptake 25%-35%
Urea nitrogen, serum 7-18 mg/dL
Uric acid, serum 3.0-8.2 mg/dL
Hematologic Reference Range
Bleeding time 2-7 minutes
Erythrocyte count Male: 4.3-5.9 million/mm3
Female: 3.5-5.5 million mm3
Erythrocyte sedimentation rate (Westergren) Male: 0-15 mm/h
Female: 0-20 mm/h
Hematocrit Male: 41%-53%
Female: 36%-46%
Hemoglobin A1c ≤ 6 %
Hemoglobin, blood Male: 13.5-17.5 g/dL
Female: 12.0-16.0 g/dL
Hemoglobin, plasma 1-4 mg/dL
Leukocyte count and differential  
Leukocyte count 4,500-11,000/mm3
Segmented neutrophils 54%-62%
Bands 3%-5%
Eosinophils 1%-3%
Basophils 0%-0.75%
Lymphocytes 25%-33%
Monocytes 3%-7%
Mean corpuscular hemoglobin 25.4-34.6 pg/cell
Mean corpuscular hemoglobin concentration 31%-36% Hb/cell
Mean corpuscular volume 80-100 μm3
Partial thromboplastin time (activated) 25-40 seconds
Platelet count 150,000-400,000/mm3
Prothrombin time 11-15 seconds
Reticulocyte count 0.5%-1.5% of red cells
Thrombin time < 2 seconds deviation from control
Volume  
Plasma Male: 25-43 mL/kg
Female: 28-45 mL/kg
Red cell Male: 20-36 mL/kg
Female: 19-31 mL/kg
Cerebrospinal Fluid Reference Range
Cell count 0-5/mm3
Chloride 118-132 mEq/L
Gamma globulin 3%-12% total proteins
Glucose 40-70 mg/dL
Pressure 70-180 mm H2O
Proteins, total < 40 mg/dL
Sweat Reference Range
Chloride 0-35 mmol/L
Urine  
Calcium 100-300 mg/24 h
Chloride Varies with intake
Creatinine clearance Male: 97-137 mL/min
Female: 88-128 mL/min
Estriol, total (in pregnancy)  
30 wks 6-18 mg/24 h
35 wks 9-28 mg/24 h
40 wks 13-42 mg/24 h
17-Hydroxycorticosteroids Male: 3.0-10.0 mg/24 h
Female: 2.0-8.0 mg/24 h
17-Ketosteroids, total Male: 8-20 mg/24 h
Female: 6-15 mg/24 h
Osmolality 50-1400 mOsmol/kg H2O
Oxalate 8-40 μg/mL
Potassium Varies with diet
Proteins, total < 150 mg/24 h
Sodium Varies with diet
Uric acid Varies with diet
Body Mass Index (BMI) Adult: 19-25 kg/m2
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(M1.PH.75) At 10 a.m. this morning, a semi-truck carrying radioactive waste toppled over due to a blown tire. One container was damaged, and a small amount of its contents leaked into the nearby river. You are a physician on the government's hazardous waste committee and must work to alleviate the town's worries and minimize the health hazards due to the radioactive leak. You decide to prescribe a prophylactic agent to minimize any retention of radioactive substances in the body. Which of the following do you prescribe? Review Topic

QID: 106841
1

Methylene blue

25%

(6/24)

2

Vitamin C

4%

(1/24)

3

Potassium iodide

38%

(9/24)

4

EDTA

12%

(3/24)

5

Succimer

21%

(5/24)

M1

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(M1.PH.75) A steel welder presents to his family physician with a one-week history of intense abdominal cramping with nausea, vomiting, constipation, headaches, myalgias, and arthralgias. He claims that the symptoms started about two months after he began work on replacing the pipes in an early 20th century house. Blood was taken and he was found to have a microcytic, hypochromic anemia with basophilic stippling. Which of the following is the best treatment for his symptoms? Review Topic

QID: 106842
1

Deferoxamine

12%

(10/83)

2

EDTA

71%

(59/83)

3

Deferasirox

2%

(2/83)

4

Prussian blue

5%

(4/83)

5

N-acetylcysteine

6%

(5/83)

M1

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(M1.PH.1) A 5-year-old boy is brought to the emergency room lapsing in and out of consciousness. The mother reports that 30 minutes ago, the young boy was found exiting the garage severely confused. A container of freshly spilled antifreeze was found on the garage floor. The next appropriate step would be to administer: Review Topic

QID: 107080
1

Dimercaprol

12%

(18/145)

2

N-acetylcysteine

6%

(9/145)

3

Ammonium chloride

3%

(4/145)

4

Flumazenil

6%

(9/145)

5

Fomepizole

69%

(100/145)

M1

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