20. Toxicology & Antidotes

Question 1

A 100 kg patient is receiving intravenous heparin at 1500 units/hour for the past 5 hours. The patient is now actively bleeding. The team wishes to reverse the heparin. How much protamine sulfate should be administered?

A. 1 mg
B. 10 mg
C. 30 mg
D. 70 mg
E. 100 mg

Answer 1

C. 1 mg of protamine neutralizes approximately 100 units of heparin. The amount of protamine required to reverse heparin would equate to the amount needed to neutralize the amount of heparin administered in the last 2-2.5 hours. The maximum dose of protamine to be administered as a single dose is 50 mg due to risk of anaphylactic reactions at higher doses.

Question 1

A patient presents to the emergency room with an irregular pulse, confusion, palpitations, loss of appetite, and vision changes. Lab results reveal a high digoxin level. Which antidote is most appropriate for digoxin toxicity?

A. Dimercaprol
B. Glucagon
C. Fomepizole
D. Flumazenil
E. DigiFab

Answer 1

E. DigiFab 40 mg vial binds about 0.5 mg digoxin. When neither amount ingested nor digoxin level is known, adult dose is 20 vials.

Question 2

A frantic father brings his child to the emergency room and reports that his child ate an unknown amount of his nicotine gum. The child appears to have difficulty breathing, appears confused, and is drooling. Which of the following is a correct recommendation? (Select ALL that apply.)

A. Provide supportive care
B. Administer atropine, if tachycardic
C. Administer pralidoxime, if tachycardic
D. Administer atropine, if bradycardic
E. Administer pralidoxime, if bradycardic

Answer 2

A, D. Management is mostly supportive; atropine is a nicotinic receptor antagonist and should be given to treat symptomatic bradycardia.

Question 3

A mother finds her 6-year-old son unconscious on the floor with an empty bottle of amitriptyline next to him. What would be the most important steps to take first?

A. Call 911 and initiate CPR if the child is not breathing.
B. Call the child’s primary care physician.
C. Bring the child to the nearest urgent care center.
D. Administer ipecac syrup.
E. Administer activated charcoal.

Answer 3

A. Emergency help should be contacted immediately (911) and CPR should be performed if the child is not breathing or has no pulse.

Question 3

Why is the use of sorbitol not preferred as a decontamination agent?

A. It can cause respiratory failure
B. It can cause hyperglycemia in diabetic patients
C. It can induce vomiting and cause electrolyte disturbances
D. It can induce seizures
E. It can cause hypoglycemia in diabetic patients

Answer 3

C. Sorbitol should be avoided because it can induce vomiting and cause electrolyte disturbances. For some orally ingested compounds taken in potentially toxic amounts, activated charcoal is preferred.

Question 4

A fire occurred in a nightclub and many people were admitted to the hospital due to cyanide poisoning released from the burning of foam from the building interior. The solution in the pharmacy’s Cyanokit is dark red in color. What is the best course of action?

A. Discard the Cyanokit, the solution is oxidized and is no longer effective.
B. Use the Cyanokit, the solution is supposed to be dark red.
C. Place the Cyanokit in the freezer until the solution becomes clear.
D. Place the Cyanokit in the refrigerator until the solution becomes clear.
E. Place the Cyanokit at room temperature until the solution becomes clear.

Answer 4

B. Cyanokit solutions should be visually inspected for particulate matter and color prior to administration. Discard if particulate matter is present or solution is not dark red.

Question 5

A healthy-appearing toddler presents to the emergency department with his grandmother, who is concerned that the child may have overdosed on Tylenol. The grandmother states that the child was playing with an open Tylenol bottle on the floor. Which of the following is a correct course of action?

A. Monitor patient for symptoms before initiating N-acetylcysteine.
B. Initiate N-acetylcysteine immediately regardless of symptoms.
C. Confirm overdose with acetaminophen level before initiating N-acetylcysteine.
D. Provide supportive care and 500 mL of sodium bicarbonate.
E. Provide naloxone by the intravenous route with supportive care.

Answer 5

B. N-acetylcysteine restores hepatic glutathione (acts as a glutathione substrate). It should be initiated immediately if overdose is suspected regardless of symptoms. Oral: 140 mg/kg x1, followed by 70 mg/kg every 4 hours x17 additional doses. Repeat dose if emesis occurs within 1 hour of administration. IV: 150 mg/kg IV over 60 minutes, followed by 50 mg/kg IV over 4 hours, followed by 100 mg/kg IV over 16 hours.

Question 5

A patient comes to the emergency department with respiratory depression and significant sedation. Paramedics found her down in her apartment with an empty bottle of Ativan on the floor. Which of the following is the appropriate antidote to give this patient?

A. Sodium bicarbonate
B. Flumazenil
C. Ipecac syrup
D. Sodium polystyrene sulfonate
E. Dimercaprol

Answer 5

B. Flumazenil is the antidote for benzodiazepines. Also used off-label for hypnotic overdose (Ambien).

Question 6

A patient complains of eye tearing, increased sweating and frequent bowel movements. It is discovered that the patient is a farmer who frequently handles insecticides such as malathion. The patient’s symptoms are consistent with malathion poisoning, what antidote should the pharmacist recommend?

A. Atropine
B. Pralidoxime
C. Atropine and pralidoxime
D. N-acetylcysteine
E. N-acetylcysteine and pralidoxime

Answer 6

C. Both atropine and pralidoxime should be used concurrently to treat organophosphate overdose.

Question 7

What are different types of child-resistant (C-R) containers designed to prevent accidental poisoning in children? (Select ALL that apply.)

A. Screw caps that require the user to press down while turning
B. Easy open caps
C. Unit-dose packaging
D. Cardboard non-adherence packaging
E. Ziplock bags

Answer 7

A, C. Common C-R packaging includes screw caps that require more than a simple turn to open (such as having the user press down with the palm when turning to open), unit dose packaging and the card adherence and safety packaging that require the user to press on one side while pulling the medication card out of the other side.

Question 8

A patient comes to the emergency department for an overdose on Norvasc. Which of the following an appropriate antidote to give to this patient?

A. Sodium bicarbonate
B. Physostigmine
C. Ipecac syrup
D. Calcium chloride 10%
E. Albuterol

Answer 8

D. Calcium chloride 10% is an antidote for a calcium channel blocker overdose.

Question 9

A jaundiced patient presents to the emergency department drowsy and lethargic. A family member states that the patient ingested 30 acetaminophen tablets a couple of hours ago. What is the antidote for acetaminophen overdose?

A. Naloxone
B. Thiamine
C. N-acetylcysteine
D. Flumazenil
E. Aspirin

Answer 9

C. N-acetylcysteine acts as a sulfhydryl-group donor and results in regeneration of glutathione which is needed for the clearance of acetaminophen’s toxic metabolite, N-acetyl-p-benzoquinoneimine (NAPQI).

Question 11

A dog with a big snooping nose was bitten by a scorpion. If the owner is willing to spend quite a bit of money, what antidote can be provided?

A. Napthalene
B. Antivenin
C. L-carnitine
D. Dimercaprol
E. Sodium bicarbonate

Answer 11

B. Antivenom (or antivenin or antivenen) is used to treat venomous bites or stings from several types of snakes, and from scorpions. Snake antivenin is extracted by milking venom from the snake while the animal is alive, by a very brave person. Thus, the antidote is expensive. L-carnitine is used for hyperammonemia from valproic acid (valproate).

Question 12

Which non-prescription drugs have child-resistant containers to reduce the risk of accidental poisoning? (Select ALL that apply.)

A. Ibuprofen
B. Tylenol
C. Aspirin
D. Oxymetazoline
E. Benadryl

Answer 12

A, B, C, D, E. Prescription drugs containing iron, diphenhydramine, acetaminophen, salicylates, NSAIDs, and vasoconstrictors (e.g., oxymetazoline), and drugs that have switched from prescription to over-the-counter all require child-resistant containers.

Question 13

A patient is admitted to the hospital with alcohol intoxication. What should be administered to prevent alcohol-induced encephalopathy?

A. Thiamine
B. Pyridoxine
C. Folic Acid
D. Phytonadione
E. Cyanacobalamin

Answer 13

A. Thiamine is vitamin B1.

Question 14

A community in California was sprayed with an organophosphate pesticide. A child was outside when the plane flew over his yard. What symptoms of toxicity should his parents watch out for in their son?

A. Psychosis, self-hurt, anxiety, anger
B. Eye tearing, salivation, sweating, and frequent bowel movements
C. Dry eyes, dry mouth, constipation, urinary retention
D. Tremors and seizures, ataxia, muscle spasticity
E. Sedation, respiratory depression, tetanus

Answer 14

B. Other symptoms of organophosphate toxicity can include coughing, nausea, vomiting and increased urination. These are cholinergic symptoms.

Question 14

A patient on Coumadin is scheduled for elective knee surgery. Which of the following is used to reverse the effects of Coumadin?

A. Thiamine
B. Pyridoxine
C. Phytonadione
D. Pyrazinamide
E. Protamine

Answer 14

C. Phytonadione (vitamin K) is used to reverse warfarin.

Question 16

A 19-year-old college student arrives to the emergency room extremely agitated and restless. He states he took “a lot more” of his Adderall than prescribed. Upon examination, he is tachycardic, hypertensive, and has dilated pupils. Along with supportive care, which of the following medications can be administered?

A. Dextrose
B. Lorazepam
C. Protamine
D. Leucovorin
E. Sodium bicarbonate

Answer 16

B. Benzodiazepines may be administered for stimulant overdose, especially to treat agitation and/or seizures.

Question 17

A hospitalized patient is using heparin. She requires immediate surgery. Which of the following agents will reverse the effects of heparin?

A. Phytonadione
B. Atropine
C. Protamine
D. N-acetylcysteine
E. Atropine/pralidoxime

Answer 17

C. Protamine is the antidote for heparin. 1 mg of protamine will reverse about 100 units of heparin.

Question 18

The antidote for methanol and ethylene glycol overdose is:

A. Naloxone
B. Fomepizole
C. N-acetylcysteine
D. Flumazenil
E. Cyanocobalamin

Answer 18

B. Fomepizole is a competitive inhibitor of alcohol dehydrogenase which is required for conversion of methanol and ethylene glycol to its toxic metabolites.

Question 19

A mother informs the pharmacist that her two year-old child may have ingested some of her iron tablets. Which of the following statements are correct? (Select ALL that apply.)

A. The antidote for iron overdose is naloxone.
B. A period of latency can occur after initial GI symptoms and prior to the onset of severe organ damage.
C. In a young child, overdose can occur with as little as 5-6 tablets.
D. Iron overdose is most common in the elderly, due to increased gut absorption.
E. Iron overload can be treated with the chelating agents deferoxamine, deferiprone and deferasirox.

Answer 19

B, C, E. Iron overdoses are common in children and can cause serious toxicities, including severe organ damage. Ingestion of iron tables is treated with deferoxamine. Iron overdose due to blood transfusions is treated with all three of the above agents.

Question 20

Select the mechanism of action for atropine:

A. Atropine is mu-receptor antagonist.
B. Atropine is an acetylcholine agonist.
C. Atropine blocks acetylcholine at the muscarinic acetylcholine receptor.
D. Atropine is beta-adrenergic agonist at the beta-2 receptors, located primarily in lung tissue.
E. Atropine is beta-adrenergic agonist at both the beta-1 and beta-2 receptors.

Answer 20

C. By blocking acetylcholine, atropine is effective at treating “cholinergic” symptoms from organophosphate poisoning or other cholinergic overdose.

Question 22

A 30 year old male went out for his birthday last night. He consumed over 15 alcoholic beverage and now presents to the Emergency Department with presumed alcohol poisoning. How should this patient be treated?

A. Correct hyperglycemia and provide supportive care
B. Correct hypoglycemia and provide supportive care
C. Administer fomepizole and provide supportive care
D. Administer flumazenil and provide supportive care
E. Administer dimercaprol and provide supportive care

Answer 22

B.

Question 23

A 24 year-old man has ingested belladonna or “deadly nightshade” This plant is rich in anticholinergic compounds. Choose the correct statements: (Select ALL that apply.)

A. He may experience SLUDGE (salivation, lacrimation, urination, defecation, GI upset, emesis) syndrome.
B. He should receive intravenous diphenhydramine to counteract the toxicity.
C. With anticholinergic overdose, delirium is likely.
D. He should receive the antidote physostigmine.
E. These compounds are non-toxic. He will not require any treatment.

Answer 23

C, D. A few plants (notably belladonna) and anticholinergic drugs and some psychiatric medications can cause anticholinergic toxicity. The peripheral symptoms of constipation, dry mouth, urinary retention and dry/blurry vision can present, along with tachycardia, increased body temperature and delirium. Benzodiazepines can be used in any delirium presentation to calm the patient down. The antidote for anticholinergic toxicity is physostigmine.

Question 24

Caitlin, a 5-year-old child, has accidentally ingested approximately eight tablets of acetaminophen twenty minutes ago. She is conscious with no apparent symptoms. Her mother has contacted poison control and has been instructed the best course of action would be to:

A. Instruct the child to lie down and drink plenty of fluids.
B. Administer protamine.
C. Administer ipecac syrup.
D. Administer phytonadione.
E. Administer activated charcoal.

Answer 24

E. Activated charcoal is effective if administered within one hour of ingestion of a toxic substance. Ipecac syrup is no longer commercially available and no longer recommended to induce emesis.

Question 25

A newly diagnosed type 1 diabetic patient presents to his primary care physician with dizziness, confusion, weakness, sweating, and hunger. He has worked over 60 hours a week, has skipped meals did not adjust his insulin. His finger stick blood glucose reading in the office is 49 mg/dL. The best recommendation for this patient is:

A. Insulin
B. Glucagon
C. Glucose
D. Octreotide
E. Epinephrine

Answer 25

C. In conscious individuals, 15-20 grams of glucose (or any carbohydrate that contains glucose can be used) to treat hypoglycemia. Some patients carry glucose tablets. Glucagon is only given to treat hypoglycema patient when he or she is unconscious or not conscious enough to self-treat.

Question 26

A homeless man is admitted to the emergency room with pinpoint pupils, blue lips, and shallow breathing. He is unresponsive to verbal commands. Opioid overdose is suspected. Which of the following is recommended?

A Atropine
B. Evzio
C. Narcan
D. Flumazenil
E. DigiFab

Answer 26

C. Recommend Narcan, Evzio also contains naloxone, but is an auto injector for emergency treatment outside of the hospital.

Question 27

What is the rationale behind providing vitamin B1 to alcoholics?

A. To reduce the risk of liver damage from the alcohol.
B. To reduce the risk of brain damage, also called “alcoholic brain disease.”
C. To reduce the risk of ataxia and falls.
D. To encourage a healthy diet and reduce stress.
E. It is more easily absorbed than other forms of B vitamins.

Answer 27

B. Alcohol consumption can damage the brain through numerous mechanisms; one of these mechanisms involves the reduced availability thiamine (vitamin B1), an essential micronutrient. Wernicke-Korsakoff syndrome includes permanent mental impairment, and psychosis. Efforts should be made to avoid this condition. Long-term thiamine (B1) deficiency from alcoholism, or, less commonly from malabsorption conditions, can cause this condition.

Question 29

A parent asks the pharmacist for quick advice: her child has sprayed a household chemical in his eye and it is burning. What should the pharmacist recommend?

A. Rinse eye with water (not too strong) from the tap or hose for at least 15 minutes.
B. Neutralize the chemical with a weak solution made with water and dishwashing soap.
C. Do not do anything; run him to the emergency department.
D. Neutralize the chemical with baking soda.
E. Administer activated charcoal.

Answer 29

A. Any chemical exposure to the eye should be evaluated. Poison control can be called for further advice at the toll-free number.

Question 30

Joan is positive for tuberculosis and has been prescribed a regimen of rifampin, isoniazid, pyrazinamide, and ethambutol for 8 weeks. She presents to the emergency room with seizures related to acute ingestion of an unknown amount of isoniazid. Which one of the following medications would be the most appropriate to administer?

A. Pyridoxine (vitamin B6)
B. Cyanocobalamin (vitamin B12)
C. Deferoxamine
D. Atropine
E. Phytonadione (vitamin K)

Answer 30

A. Pyridoxine (vitamin B6), in higher intravenous doses, is used to treat isoniazid-induced toxicity. It is taken daily with isoniazid to reduce the risk of neuropathic damage.

Question 31

A female patient comes to the emergency department with a low blood pressure, low pulse and mental confusion. Her husband states she swallowed an entire bottle of atenolol. Which of the following is the appropriate antidote to give to this patient?

A. Sodium bicarbonate
B. Glucagon
C. Protamine
D. Calcium chloride 10%
E. Albuterol

Answer 31

B. The initial management consists of supportive care measures, such as providing fluids. Glucagon is used if needed. Glucagon acts independent of beta-adrenergic receptors to increase activation of adenylatecyclase.

Question 32

A 4-year-old child has accidentally ingested an unknown amount of Bengay, which contains methyl salicylate. She is experiencing hyperventilation, diaphoresis, nausea, and vomiting. Which medication can be used to treat her condition?

A. Mephyton
B. Sodium bicarbonate
C. N-acetylcysteine
D. Flumazenil
E. DigiFab

Answer 32

B. Topical agents, such as Bengay, can contain toxic amounts of salicylate, especially if consumed by a young child. Sodium bicarbonate is an alkalinizing agent to reverse salicylate toxicity. Salicylate causes metabolic acidosis, hence reversed with bicarbonate.

Question 33

A babysitter is watching a brother and sister, ages 4 and 5 years old. She suspects that the younger child may have consumed some pills from the parent’s medicine cabinet. Who should the babysitter call for initial advice?

A. The nearest 24-hour pharmacy
B. The nearest emergency department
C. The national poison control line
D. The police department
E. The fire department

Answer 33

C.

Question 34

A patient presents to the emergency department with gastrointestinal perforation. A lab test reveals low white blood cells, red blood cells and platelets and a high serum methotrexate level. Which of the following should be initiated?

A. Pyridoxine
B. Hyaluronidase
C. Dimethyl sulfoxide
D. Dexrazoxane
E. Leucovorin or levoleucovorin

Answer 34

E. Leucovorin is folinic acid. Both leucovorin and levoleucovorin provide folate rescue. The additional antidotes above can be found in the oncology chapter.