Toxicology

Question 1

What are the initial priorities in treating a suspected overdose?

Answer 1

Airway, breathing, circulation (ABCs), vital signs, IV access, labs, ECG, decontamination if appropriate.

Question 2

What are three common decontamination methods?

Answer 2

Activated charcoal, whole bowel irrigation, hemodialysis.

Question 3

What is the antidote for salicylate toxicity?

Answer 3

Sodium bicarbonate for urine alkalinization.

Question 4

When is sodium bicarbonate indicated in salicylate toxicity?

Answer 4

Serum salicylate >30 mg/dL, metabolic acidosis, or altered mental status.

Question 5

What is the antidote for benzodiazepine overdose?

Answer 5

Flumazenil (with caution due to risk of seizures).

Question 6

What are signs of sedative overdose?

Answer 6

CNS depression, respiratory depression, slurred speech, ataxia.

Question 7

What is the antidote for TCA overdose?

Answer 7

Sodium bicarbonate (for QRS >100 msec, arrhythmias, hypotension).

Question 8

What is the mechanism of sodium bicarbonate in TCA overdose?

Answer 8

Increases sodium gradient, improving conduction and stabilizing myocardium.

Question 9

How is extrapyramidal toxicity from antipsychotics managed?

Answer 9

Benztropine or diphenhydramine IM/IV, followed by PO therapy for 3–4 days.

Question 10

What is the treatment for neuroleptic malignant syndrome (NMS)?

Answer 10

Stop offending agent, cool patient, give dantrolene or bromocriptine, use benzodiazepines.

Question 11

What is the classic triad of serotonin syndrome?

Answer 11

Altered mental status, autonomic instability, neuromuscular abnormalities.

Question 12

What is the antidote for serotonin syndrome?

Answer 12

Cyproheptadine (Periactin®).

Question 13

What is the antidote for digoxin toxicity?

Answer 13

Digoxin immune Fab (Digibind®).

Question 14

What are indications for Digibind use?

Answer 14

Severe bradycardia or heart block, ventricular arrhythmias, serum digoxin >10–15 ng/mL, ingestion >10 mg.

Question 15

What is first-line antidote for CCB or BB toxicity?

Answer 15

Calcium, glucagon, high-dose insulin therapy, and vasopressors.

Question 16

What is the mechanism of action of high-dose insulin in overdose?

Answer 16

Improves inotropy and glucose utilization in myocardium.

Question 17

What is the antidote for iron toxicity?

Answer 17

Deferoxamine (Desferal®).

Question 18

What are signs of iron toxicity?

Answer 18

Vomiting, abdominal pain, shock, metabolic acidosis, hyperglycemia, liver failure.

Question 19

What is the hallmark sign of deferoxamine therapy working?

Answer 19

Vin rose (pink-red) urine.

Question 20

What is the antidote for salicylate toxicity and its mechanism?

Answer 20

Sodium bicarbonate; alkalinizes urine to enhance renal elimination of salicylates.

Question 21

What is the target urine pH for salicylate toxicity management?

Answer 21

7.5 to 8.0.

Question 22

What is the antidote for benzodiazepine overdose and its mechanism?

Answer 22

Flumazenil; competitive antagonist at the GABA-A receptor.

Question 23

What is the initial dose of flumazenil for benzodiazepine reversal?

Answer 23

0.2 mg IV over 15 seconds, may repeat at 1-minute intervals (max 3 mg/hour).

Question 24

What is the role of sodium bicarbonate in TCA overdose?

Answer 24

Increases serum pH and sodium load, countering cardiac membrane depressant effects of TCAs.

Question 25

What is the bolus dose of sodium bicarbonate in TCA overdose?

Answer 25

1–2 mEq/kg IV bolus, repeated as needed based on QRS interval and pH.

Question 26

What is the mechanism of digoxin immune Fab?

Answer 26

Binds free digoxin, allowing renal excretion of inactive Fab–digoxin complex.

Question 27

What is the formula for digoxin Fab dosing in acute ingestion?

Answer 27

Number of vials = total ingested (mg) × 0.8 / 0.5.

Question 28

What is the formula for digoxin Fab dosing in chronic toxicity?

Answer 28

Number of vials = (serum level ng/mL) × weight (kg) / 100.

Question 29

What is the mechanism of action of deferoxamine?

Answer 29

Chelates free iron to form ferrioxamine, which is excreted in urine.

Question 30

What is the standard dose of deferoxamine in iron toxicity?

Answer 30

15 mg/kg/hr IV infusion (max 6 g/day); may need to continue 24–48 hrs.

Question 31

What is the mechanism of glucagon in beta blocker overdose?

Answer 31

Stimulates adenylate cyclase independently of beta-receptors to increase cAMP and improve contractility.

Question 32

What is the initial dose of glucagon in beta-blocker overdose?

Answer 32

3–5 mg IV bolus followed by 1–5 mg/hr infusion.

Question 33

What is the mechanism of high-dose insulin in CCB/BB overdose?

Answer 33

Improves myocardial glucose uptake and inotropy.

Question 34

What is the dosing for high-dose insulin therapy?

Answer 34

1 unit/kg IV bolus followed by 0.5–1 unit/kg/hr infusion, titrated to effect.

Question 35

What are the general principles of overdose and poisoning management?

Answer 35

Stabilize ABCs, identify toxin, decontaminate if needed, provide supportive care, and administer antidotes when appropriate.

Question 36

What is the role of activated charcoal in overdose management?

Answer 36

Binds ingested toxins in the GI tract to reduce absorption; most effective within 1–2 hours of ingestion.

Question 37

Which drug overdoses may be treated with sodium bicarbonate?

Answer 37

Salicylates (for urine alkalinization) and tricyclic antidepressants (for QRS widening or arrhythmias).

Question 38

What is the antidote for benzodiazepine overdose?

Answer 38

Flumazenil, a GABA receptor antagonist—used with caution due to seizure risk.

Question 39

What are key signs of serotonin syndrome?

Answer 39

Altered mental status, autonomic instability, and neuromuscular abnormalities (e.g., clonus, hyperreflexia).

Question 40

What is the antidote for digoxin toxicity?

Answer 40

Digoxin immune Fab (Digibind®), which binds digoxin and allows renal elimination.

Question 41

What are the signs and treatment of iron toxicity?

Answer 41

Abdominal pain, vomiting, shock; treat with deferoxamine which chelates iron for urinary excretion.

Question 42

What is the role of high-dose insulin in beta blocker and calcium channel blocker overdose?

Answer 42

Supports myocardial metabolism and inotropy by enhancing glucose uptake.