Toxicology

Answer: B

The most important first step in all drug overdose

cases is to try to stabilize the patient’s ABC (Answer

B is correct). This may involve the use of supplemental

oxygen or advanced airway management, establishment

of intravenous access, and administration of intrave-

nous fluids. Once the patient is stable, the process of

identifying the suspected toxin can begin (Answer D

is incorrect). This may include thoroughly examining

the patient, speaking with family or first responders,

and communicating with the patient’s physicians and

pharmacies. Blood and urine samples may be sent for

quantitative or qualitative toxicologic assays (Answer A

is incorrect). A coma cocktail may provide some benefit,

but a clear cause should be established before consider-

ing its use (Answer C is incorrect).

The patient has symptoms of an acute acetaminophen

overdose, and stabilizing the patient, together with

providing good supportive care, is indicated until a deter-

mination for additional therapy can be made (Answer B

is correct). Typical decontamination strategies may pro-

vide benefit, but they do not definitively improve patient

outcome. Magnesium citrate (and cathartics as a whole)

is not considered an effective decontamination strategy

(Answer A is incorrect). Gastric lavage is of most benefit

within the first 60 minutes of exposure, and the potential

adverse effects outweigh any potential benefit (Answer

C is incorrect). Similarly, single-dose charcoal requires

more rapid administration (Answer D is incorrect).

Answer: C

The patient is considered at high risk of developing

hepatic damage from acetaminophen and requires

therapy with intravenous acetylcysteine (Answer D is

incorrect). The dose of intravenous acetylcysteine is as

follows (doses are calculated using actual body weight):

loading dose: 150 mg/kg in 200 mL of 5% dextrose in

water for 60 minutes; maintenance dose: 50 mg/kg in

500 mL of 5% dextrose in water for 4 hours, followed

by 100 mg/kg in 1000 mL of 5% dextrose in water for

16 hours (Answer C is correct and Answer B is incor-

rect). Oral dosing of acetylcysteine is not a viable option

because of the patient’s severe nausea and vomiting

(Answer A is incorrect).

Answer: C

This patient has an acute salicylate overdose. Although

his serum salicylate concentrations are in the therapeu-

tic range, he has symptoms consistent with salicylate

toxicity, as evidenced by his nausea, tachycardia, and

respiratory alkalosis. He is currently stable, but his

serum salicylate concentrations may continue to rise;

therefore, enhanced elimination with serum bicarbonate

is the best option (Answer C is correct). His vital signs,

which are stable, should be monitored for changes;

however, although he is not experiencing signs of sig-

nificant dehydration, he would benefit from the fluid

administration of sodium bicarbonate. Sodium chloride

would be more beneficial if his vital signs were more

unstable (Answer A is incorrect). His RR, which is

elevated, should be monitored; however, he is alert and

able to communicate and therefore does not need intu-

bation at this time (Answer B is incorrect). He is also

not indicated for hemodialysis because of his moderate

symptoms, but this could be considered if his condition

deteriorates (Answer D is incorrect).

Answer: A

The most appropriate therapy for an ethylene glycol

intoxication is fomepizole (Answer A is correct). An

ethanol infusion is a possible treatment option, but it is

not preferred because of the difficulties in dosing and

adverse effects (Answer B is incorrect). Thiamine is

a cofactor in the metabolism of ethylene glycol, but it

would not be preferred to administer thiamine before

fomepizole (Answer C is incorrect). Activated charcoal

is not an option for gastric decontamination because it is

not effective for alcohols (Answer D is incorrect).

Answer: C

After the initial bolus of fomepizole, 10 mg/kg should be

administered every 12 hours. Because of the increased

clearance of fomepizole during hemodialysis, the fre-

quency is changed to every 4 hours during dialysis

(Answer C is correct and Answer A is incorrect). When

dialysis is completed, the dose returns to 10 mg/kg

administered every 12 hours; and once the patient has

been on 48 hours of therapy, dosing increases to 15 mg/

kg because of self-induction. There is no indication for a

dose increase (Answer B and D are incorrect).