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ABEM Medical Tox study materials
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ABEM Medical Tox practice questions

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Question 1General Principles of Toxicology (pharmacokinetics, risk assessment, decontamination, supportive care)

A drug with a large volume of distribution is most likely to be:

  1. High plasma protein binding
  2. Extensive distribution into tissues Correct answer.
  3. Rapid removal by hemodialysis
  4. Confinement to the vascular space

Explanation

Volume of distribution is an apparent value that relates dose to plasma concentration. A large value indicates that much of the drug has left plasma and entered tissues. It does not by itself indicate protein binding or dialyzability.

Question 2General Principles of Toxicology (pharmacokinetics, risk assessment, decontamination, supportive care)

A drug obeys first-order elimination with a half-life of 4 hours. What fraction of the original dose remains 12 hours after administration?

  1. 50%
  2. 12.5% Correct answer.
  3. 6.25%
  4. 25%

Explanation

Twelve hours represents three half-lives (12 divided by 4 equals 3). After each half-life the remaining amount is halved, so the fraction remaining is one-half cubed, or one-eighth, which is 12.5%.

Question 3General Principles of Toxicology (pharmacokinetics, risk assessment, decontamination, supportive care)

Activated charcoal is contraindicated in which situation?

  1. Suspected corrosive ingestion Correct answer.
  2. A protected airway
  3. Recent carbamazepine overdose
  4. Theophylline ingestion

Explanation

Charcoal is avoided when the ingested substance is corrosive because it obscures endoscopic evaluation and provides no meaningful adsorption. It is also avoided in patients without airway protection or with ileus.

Question 4General Principles of Toxicology (pharmacokinetics, risk assessment, decontamination, supportive care)

Gastric lavage is most likely to be beneficial when performed:

  1. 12 hours after a sustained-release overdose
  2. in a patient with an unprotected airway
  3. within 1 hour of a severe ingestion Correct answer.
  4. after activated charcoal has been administered

Explanation

Gastric lavage has a narrow window and is considered mainly for recent, potentially lethal ingestions. It is not routinely performed after charcoal or in patients whose airway is unprotected because of aspiration risk.

Question 5General Principles of Toxicology (pharmacokinetics, risk assessment, decontamination, supportive care)

Whole bowel irrigation is best indicated for:

  1. Hydrocarbon ingestion with aspiration risk
  2. Massive iron overdose with tablet burden Correct answer.
  3. Small ingestions of activated charcoal alone
  4. Caustic alkali ingestion

Explanation

Whole bowel irrigation can move unabsorbed tablets through the gut, particularly with iron or sustained-release products. It is avoided with corrosives, hydrocarbons, and hemodynamic instability.

Question 6General Principles of Toxicology (pharmacokinetics, risk assessment, decontamination, supportive care)

Urinary alkalinization is used in salicylate poisoning because it:

  1. enhances salicylate protein binding
  2. increases gastric absorption
  3. reduces renal tubular blood flow
  4. ionizes drug in the tubule Correct answer.

Explanation

Alkaline urine converts salicylic acid to its ionized form, which is less able to cross tubular membranes and be reabsorbed. This enhances renal elimination. Urinary alkalinization does not work by increasing protein binding or reducing blood flow.

Question 7General Principles of Toxicology (pharmacokinetics, risk assessment, decontamination, supportive care)

Which finding best predicts that a toxin will be effectively removed by hemodialysis?

  1. Low protein binding and small Vd Correct answer.
  2. Extensive tissue sequestration
  3. Volume of distribution greater than 100 L
  4. Molecular weight above 5000 Da

Explanation

Hemodialysis removes solute from plasma, so it works best when the toxin has a small volume of distribution, low protein binding, and low molecular weight. Large tissue reservoirs and large molecules are poorly cleared.

Question 8General Principles of Toxicology (pharmacokinetics, risk assessment, decontamination, supportive care)

Ethanol exhibits zero-order elimination at toxic concentrations. This means that:

  1. elimination half-life remains constant
  2. constant amount eliminated per unit time Correct answer.
  3. clearance rises as concentration rises
  4. constant fraction eliminated per unit time

Explanation

Zero-order kinetics occurs when metabolic enzymes are saturated, so a fixed amount is eliminated per unit time regardless of concentration. In contrast, first-order elimination removes a constant fraction and has a constant half-life.

Question 9General Principles of Toxicology (pharmacokinetics, risk assessment, decontamination, supportive care)

Inhibition of cytochrome P450 enzymes by a co-ingested drug most commonly leads to:

  1. Increased renal clearance of the substrate
  2. Decreased plasma concentration of the substrate
  3. Increased plasma concentration of the substrate Correct answer.
  4. Reduced gastrointestinal absorption

Explanation

Cytochrome P450 inhibition slows oxidative metabolism of the substrate, so plasma concentrations can rise and toxicity may increase. Enzyme induction has the opposite effect.

Question 10General Principles of Toxicology (pharmacokinetics, risk assessment, decontamination, supportive care)

The no-observed-adverse-effect level (NOAEL) is best described as:

  1. dose at which 1% of subjects respond
  2. highest dose without observed adverse effect Correct answer.
  3. dose producing a 50% maximal response
  4. lowest dose with a significant adverse effect

Explanation

The NOAEL is the highest dose tested in a study that does not produce a statistically or biologically significant adverse effect. It is used as a starting point for deriving safe exposure limits.

Question 11General Principles of Toxicology (pharmacokinetics, risk assessment, decontamination, supportive care)

A benchmark dose (BMD) approach is preferred over NOAEL because it:

  1. requires no uncertainty factors
  2. models the full dose-response curve Correct answer.
  3. is independent of study quality
  4. uses only the highest dose tested

Explanation

Benchmark dose modeling fits the entire dose-response dataset and estimates the dose associated with a specified response level. This uses more information than selecting a single no-effect dose and is less dependent on dose spacing.

Question 12General Principles of Toxicology (pharmacokinetics, risk assessment, decontamination, supportive care)

A standard uncertainty factor of 10 for intraspecies variability is applied because:

  1. exposure duration is uncertain
  2. humans vary in toxicant susceptibility Correct answer.
  3. the NOAEL is a precise threshold
  4. animal studies are always more sensitive

Explanation

The intraspecies factor accounts for differences among humans, such as genetics, age, disease, and nutritional status. Interspecies and duration factors address different sources of uncertainty.

Question 13General Principles of Toxicology (pharmacokinetics, risk assessment, decontamination, supportive care)

For dermal exposure to a liquid organophosphate, initial decontamination should include:

  1. delaying washing until antidotes are given
  2. scrubbing the skin vigorously with a stiff brush
  3. removing clothing and washing with soap and water Correct answer.
  4. applying a tight occlusive dressing

Explanation

Removing contaminated clothing and washing the skin with soap and water reduces ongoing absorption and protects providers. Vigorous scrubbing can damage skin and increase absorption.

Question 14General Principles of Toxicology (pharmacokinetics, risk assessment, decontamination, supportive care)

After ocular exposure to an acid, the most important immediate intervention is:

  1. systemic corticosteroid administration
  2. application of topical anesthetic only
  3. pressure patching of the eye
  4. prolonged irrigation with water or saline Correct answer.

Explanation

Immediate and prolonged irrigation dilutes and removes the acid, limiting tissue injury. Anesthetic drops may help with comfort but do not replace irrigation.

Question 15General Principles of Toxicology (pharmacokinetics, risk assessment, decontamination, supportive care)

A comatose poisoned patient has a Glasgow Coma Scale score of 6. The most appropriate airway management is:

  1. oral airway without suction
  2. nasopharyngeal airway and observation
  3. endotracheal intubation Correct answer.
  4. observation with pulse oximetry

Explanation

A GCS score of 8 or less generally indicates the need for definitive airway protection because of impaired protective reflexes. Endotracheal intubation also facilitates ventilation and safe administration of charcoal if needed.

Question 16General Principles of Toxicology (pharmacokinetics, risk assessment, decontamination, supportive care)

A patient with drug-induced seizures that persist after one dose of a benzodiazepine should next receive:

  1. flumazenil
  2. a second benzodiazepine or barbiturate Correct answer.
  3. activated charcoal without airway protection
  4. naloxone

Explanation

Seizures that fail an initial benzodiazepine dose are treated with additional benzodiazepine or a barbiturate such as phenobarbital. Flumazenil can precipitate seizures and is not a treatment for status epilepticus.

Question 17General Principles of Toxicology (pharmacokinetics, risk assessment, decontamination, supportive care)

In sympathomimetic-induced hyperthermia, the priority intervention is:

  1. antipyretics such as acetaminophen
  2. physical cooling and benzodiazepines Correct answer.
  3. forced diuresis with furosemide
  4. neuromuscular blockade without sedation

Explanation

Sympathomimetic hyperthermia is driven by increased muscular activity and agitation, so sedation with benzodiazepines and active cooling are central. Antipyretics act on the hypothalamic set point and are not effective for this mechanism.

Question 18General Principles of Toxicology (pharmacokinetics, risk assessment, decontamination, supportive care)

Naloxone reverses opioid toxicity by:

  1. blocking opioid absorption
  2. increasing opioid metabolism
  3. enhancing renal excretion
  4. competitively antagonizing opioid receptors Correct answer.

Explanation

Naloxone is a competitive opioid receptor antagonist that displaces opioids from mu receptors. It does not alter metabolism, absorption, or renal elimination.

Question 19General Principles of Toxicology (pharmacokinetics, risk assessment, decontamination, supportive care)

N-acetylcysteine is most effective for acetaminophen toxicity when given:

  1. at least 24 hours after ingestion
  2. within 8 to 10 hours Correct answer.
  3. after liver failure has developed
  4. only after charcoal fails

Explanation

N-acetylcysteine replenishes glutathione and detoxifies the reactive metabolite before hepatocellular injury becomes established. Benefit is greatest when started within 8 to 10 hours of ingestion, though later treatment may still help.

Question 20General Principles of Toxicology (pharmacokinetics, risk assessment, decontamination, supportive care)

Fomepizole is used in methanol poisoning because it:

  1. directly neutralizes formic acid
  2. inhibits alcohol dehydrogenase Correct answer.
  3. blocks methanol absorption
  4. enhances methanol renal clearance

Explanation

Fomepizole inhibits alcohol dehydrogenase, preventing methanol from being converted to formaldehyde and formic acid. This reduces the formation of toxic metabolites while methanol is eliminated.

Question 21General Principles of Toxicology (pharmacokinetics, risk assessment, decontamination, supportive care)

Sodium bicarbonate is given in tricyclic antidepressant overdose primarily to:

  1. prevent seizures
  2. increase urinary excretion of parent drug
  3. reverse anticholinergic effects
  4. narrow the QRS via sodium loading Correct answer.

Explanation

Sodium bicarbonate provides a sodium load and alkalinization, which stabilize cardiac sodium channels and narrow the QRS. It is not primarily used to enhance urinary elimination or reverse anticholinergic findings.

Question 22General Principles of Toxicology (pharmacokinetics, risk assessment, decontamination, supportive care)

Intravenous lipid emulsion is best established as rescue therapy for:

  1. local anesthetic systemic toxicity Correct answer.
  2. iron poisoning
  3. methanol toxicity
  4. acetaminophen hepatotoxicity

Explanation

Lipid emulsion is a recognized rescue treatment for local anesthetic systemic toxicity, especially with bupivacaine. Evidence for other poisonings is much weaker and it is not standard therapy for acetaminophen, iron, or methanol.

Question 23General Principles of Toxicology (pharmacokinetics, risk assessment, decontamination, supportive care)

A NOAEL of 20 mg/kg/day is identified in a chronic animal study. Using a 10-fold interspecies factor, a 10-fold intraspecies factor, and a 10-fold factor for study limitations, the reference dose is:

  1. 0.02 mg/kg/day Correct answer.
  2. 2 mg/kg/day
  3. 0.2 mg/kg/day
  4. 20 mg/kg/day

Explanation

The reference dose is the NOAEL divided by the product of the uncertainty factors. The product is 10 times 10 times 10, or 1000, so 20 mg/kg/day divided by 1000 equals 0.02 mg/kg/day.

Question 24General Principles of Toxicology (pharmacokinetics, risk assessment, decontamination, supportive care)

For a drug that is 95% protein bound, which statement is most accurate?

  1. Only the free 5% is pharmacologically active Correct answer.
  2. The volume of distribution is always small
  3. Tissue binding is negligible
  4. Hemodialysis will readily remove the drug

Explanation

Only unbound drug is free to reach receptors and produce effect, so extensive protein binding limits the active fraction. Dialysis and tissue distribution depend on additional factors and cannot be inferred from binding alone.

Question 25General Principles of Toxicology (pharmacokinetics, risk assessment, decontamination, supportive care)

Activated charcoal is most effective when administered:

  1. with a cathartic routinely
  2. within 1 hour of ingestion Correct answer.
  3. after gastric lavage is performed
  4. after 4 hours have passed

Explanation

Charcoal adsorbs drug best before substantial absorption has occurred, so the greatest benefit is within about 1 hour. Later administration may still be considered for sustained-release or massive ingestions.

Question 26General Principles of Toxicology (pharmacokinetics, risk assessment, decontamination, supportive care)

A drug follows first-order elimination with a half-life of 6 hours. After 24 hours, approximately what fraction of the original dose remains?

  1. 3.125%
  2. 6.25% Correct answer.
  3. 25%
  4. 12.5%

Explanation

First-order elimination removes a constant fraction per half-life, so the amount remaining after n half-lives is (1/2)^n. In 24 hours, four half-lives have elapsed (24 ÷ 6 = 4), leaving (1/2)^4 = 1/16, or 6.25%.

Question 27General Principles of Toxicology (pharmacokinetics, risk assessment, decontamination, supportive care)

A toxin has a volume of distribution of 50 L/kg. Which interpretation is most accurate?

  1. Extensive distribution into tissue compartments. Correct answer.
  2. The toxin is eliminated rapidly by the kidneys.
  3. The toxin is confined mainly to plasma.
  4. The toxin is highly protein bound in plasma.

Explanation

Volume of distribution is an apparent volume relating the dose to the plasma concentration. A very large value, such as 50 L/kg, indicates extensive distribution into tissues rather than confinement to plasma. It does not by itself establish elimination rate or the degree of protein binding.

Question 28General Principles of Toxicology (pharmacokinetics, risk assessment, decontamination, supportive care)

Chronic heavy alcohol use induces CYP2E1. Which consequence is most relevant to acetaminophen overdose?

  1. Reduced acetaminophen absorption from the gut
  2. Increased glucuronidation, which lowers toxicity risk
  3. Enhanced renal excretion of unchanged acetaminophen
  4. More NAPQI formation, increasing hepatotoxicity Correct answer.

Explanation

CYP2E1 catalyzes oxidation of acetaminophen to the reactive metabolite NAPQI. Enzyme induction shifts more drug toward this pathway and can overwhelm glutathione-dependent detoxification. This increases the risk of hepatocellular injury in overdose.

Question 29General Principles of Toxicology (pharmacokinetics, risk assessment, decontamination, supportive care)

Which statement best distinguishes phase I from phase II biotransformation?

  1. Phase I often forms reactive metabolites; phase II usually increases solubility. Correct answer.
  2. Phase II reactions always produce metabolites more toxic than the parent compound.
  3. Phase I reactions generally conjugate toxins with glucuronic acid or sulfate.
  4. Phase II reactions generally introduce functional groups via oxidation.

Explanation

Phase I reactions, such as oxidation, reduction, and hydrolysis, introduce or expose functional groups and can generate reactive intermediates. Phase II conjugation reactions, such as glucuronidation and sulfation, generally increase water solubility and promote excretion.

Question 30General Principles of Toxicology (pharmacokinetics, risk assessment, decontamination, supportive care)

A contaminant has a reference dose (RfD) of 0.02 mg/kg/day. Estimated intake is 0.05 mg/kg/day. What is the hazard quotient and its interpretation?

  1. HQ = 0.4; intake exceeds the RfD, indicating potential concern
  2. HQ = 2.5; exceeds RfD, potential concern Correct answer.
  3. HQ = 2.5; intake is below the RfD and not a concern
  4. HQ = 0.4; intake is below the RfD and not a concern

Explanation

The hazard quotient is exposure divided by the RfD: 0.05 ÷ 0.02 = 2.5. An HQ greater than 1 means estimated exposure exceeds the RfD and warrants further risk assessment; it does not prove that harm will occur.

Question 31General Principles of Toxicology (pharmacokinetics, risk assessment, decontamination, supportive care)

The LD50 of a chemical is best described as:

  1. The dose that causes toxicity in 50% of exposed animals
  2. The lowest dose that produces any observable adverse effect
  3. The dose at which 50% of the chemical is eliminated from the body
  4. Dose lethal to 50% of exposed animals under specified conditions Correct answer.

Explanation

LD50 is the median lethal dose, determined in animal testing under defined conditions and observation periods. It permits comparisons of acute lethality but does not describe nonlethal toxicity, chronic effects, or mechanism.

Question 32General Principles of Toxicology (pharmacokinetics, risk assessment, decontamination, supportive care)

Activated charcoal is most clearly contraindicated in which situation?

  1. Ingestion of a strong alkali Correct answer.
  2. Ingestion of a sustained-release tablet
  3. Ingestion of carbamazepine
  4. Ingestion of theophylline

Explanation

Charcoal is avoided after caustic ingestions because it does not adsorb the corrosive agent and can obscure endoscopic evaluation. It is also contraindicated when the airway is unprotected or bowel obstruction is present.

Question 33General Principles of Toxicology (pharmacokinetics, risk assessment, decontamination, supportive care)

Gastric lavage for a recent oral overdose is best described by which statement?

  1. It should be performed routinely for all overdoses presenting within 6 hours
  2. Benefit is greatest within 60 minutes; caustic ingestion is a contraindication Correct answer.
  3. It is preferred over activated charcoal for hydrocarbon ingestion
  4. It is safe in patients with an unprotected airway if a small-bore tube is used

Explanation

Gastric lavage is considered only for potentially life-threatening recent ingestion, generally within about 1 hour, and requires airway protection. It is contraindicated after corrosive ingestion because of perforation risk.

Question 34General Principles of Toxicology (pharmacokinetics, risk assessment, decontamination, supportive care)

Whole-bowel irrigation with polyethylene glycol solution is most appropriate for which ingestion?

  1. A small ingestion of a liquid organophosphate
  2. A patient with ileus and abdominal distension
  3. Suspected cocaine body packing Correct answer.
  4. A caustic alkali ingestion

Explanation

Whole-bowel irrigation is used for substances poorly adsorbed by charcoal, including sustained-release drugs, iron, and illicit drug packets. It is contraindicated in bowel obstruction, ileus, perforation, and corrosive ingestion.

Question 35General Principles of Toxicology (pharmacokinetics, risk assessment, decontamination, supportive care)

A worker is found unconscious in a confined space with a chemical vapor. Which initial action is most appropriate for the responding clinician?

  1. Wait for the vapor to dissipate before approaching the worker
  2. Enter the space immediately to remove the worker
  3. Remove the worker after donning proper respiratory protection Correct answer.
  4. Administer an antidote in the confined space before moving the worker

Explanation

Rescuer safety is the first priority in inhalation exposures. The patient should be removed to fresh air by personnel using appropriate respiratory protection, followed by oxygen and supportive care. Unprotected entry can create additional victims.

Question 36General Principles of Toxicology (pharmacokinetics, risk assessment, decontamination, supportive care)

A poisoned patient is hypotensive with a systolic blood pressure of 78 mmHg after an overdose. What is the most appropriate initial supportive measure?

  1. Oral activated charcoal
  2. Intravenous furosemide
  3. Intravenous isotonic crystalloid bolus Correct answer.
  4. Immediate norepinephrine infusion

Explanation

After ensuring airway and breathing, toxin-induced hypotension is initially managed with volume resuscitation using isotonic crystalloids. Vasopressors are added when hypotension persists despite adequate fluid resuscitation.

Question 37General Principles of Toxicology (pharmacokinetics, risk assessment, decontamination, supportive care)

A patient with stimulant-associated agitation and muscle rigidity has a creatine kinase of 25,000 U/L and dark urine. Which supportive intervention is most important?

  1. Neuromuscular blockade without sedation
  2. Restrict fluids to avoid pulmonary edema
  3. Aggressive IV isotonic fluids Correct answer.
  4. Oral sodium bicarbonate to alkalinize the urine

Explanation

Rhabdomyolysis is managed with early aggressive intravenous isotonic fluids to maintain urine output and limit pigment-induced kidney injury. Sedation with benzodiazepines addresses agitation and rigidity, while urinary alkalinization is optional rather than first-line.

Question 38General Principles of Toxicology (pharmacokinetics, risk assessment, decontamination, supportive care)

Syrup of ipecac is no longer recommended for routine out-of-hospital overdose management primarily because:

  1. No proven benefit; causes aspiration and prolonged vomiting Correct answer.
  2. It is effective only for hydrocarbon ingestions
  3. It reliably removes toxin from the small intestine
  4. It has no emetic effect in most patients

Explanation

Ipecac induces vomiting but has not been shown to improve outcomes and can cause aspiration, persistent vomiting, and delayed administration of charcoal or antidotes. It is therefore no longer recommended for routine overdose management.

Question 39General Principles of Toxicology (pharmacokinetics, risk assessment, decontamination, supportive care)

A patient ingested an unknown amount of a delayed-toxicity poison 2 hours ago and currently has no symptoms and normal vital signs. What is the best interpretation?

  1. Symptoms always begin within 30 minutes of ingestion
  2. Toxicity may still develop; observe and assess risk Correct answer.
  3. The patient can be discharged after a brief observation period
  4. The absence of symptoms excludes a serious ingestion

Explanation

Many toxins, including acetaminophen, iron, and sustained-release preparations, have a latent phase before clinical effects appear. The initial absence of symptoms does not exclude serious poisoning, so management is guided by the substance, dose, and expected onset.

Question 40General Principles of Toxicology (pharmacokinetics, risk assessment, decontamination, supportive care)

A 70-kg patient ingests 150 mL of a liquid containing 40 mg/mL of a toxin. What is the approximate ingested dose in mg/kg?

  1. 210 mg/kg
  2. 21 mg/kg
  3. 86 mg/kg Correct answer.
  4. 8.6 mg/kg

Explanation

The total ingested amount is 150 mL × 40 mg/mL = 6,000 mg. Dividing by body weight gives 6,000 mg ÷ 70 kg ≈ 86 mg/kg. Expressing exposure per kilogram allows comparison with toxicity thresholds and risk-assessment values.

Question 41Pharmaceutical Agents, Drugs of Abuse, and Alcohols

Which enzyme is inhibited by fomepizole in methanol poisoning?

  1. Gamma-glutamyl transferase
  2. Alcohol dehydrogenase Correct answer.
  3. Cytochrome P450 2E1
  4. Aldehyde dehydrogenase

Explanation

Fomepizole competitively inhibits alcohol dehydrogenase, the enzyme that converts methanol to formaldehyde and then formate. Blocking this step prevents the generation of toxic metabolites while methanol is eliminated.

Question 42Pharmaceutical Agents, Drugs of Abuse, and Alcohols

Which urinary crystal is most characteristic of ethylene glycol poisoning?

  1. Calcium oxalate crystals
  2. Uric acid crystals
  3. Cystine crystals
  4. Struvite (triple phosphate) crystals Correct answer.

Explanation

Ethylene glycol is metabolized to oxalate, which binds calcium and forms calcium oxalate crystals in the urine. These crystals may be monohydrate or dihydrate forms and support the diagnosis.

Question 43Pharmaceutical Agents, Drugs of Abuse, and Alcohols

A patient with isopropanol ingestion typically shows which acid-base pattern?

  1. High anion gap metabolic acidosis
  2. Normal acid-base status with ketonemia Correct answer.
  3. Respiratory alkalosis with hyperchloremia
  4. High anion gap metabolic acidosis with hypokalemia

Explanation

Isopropanol is metabolized to acetone, producing ketosis without a significant metabolic acidosis. The osmolar gap may be elevated, but the anion gap and pH usually remain near normal.

Question 44Pharmaceutical Agents, Drugs of Abuse, and Alcohols

Which antidote is first-line for suspected opioid overdose with respiratory depression?

  1. Flumazenil
  2. Physostigmine
  3. Naloxone Correct answer.
  4. Fomepizole

Explanation

Naloxone is a competitive opioid receptor antagonist that rapidly reverses opioid-induced respiratory depression. It should be given promptly while supporting ventilation.

Question 45Pharmaceutical Agents, Drugs of Abuse, and Alcohols

Which antidote replenishes glutathione stores after acetaminophen overdose?

  1. N-acetylcysteine Correct answer.
  2. Naloxone
  3. Glucagon
  4. Fomepizole

Explanation

N-acetylcysteine restores hepatic glutathione, allowing detoxification of the reactive metabolite NAPQI. It is most effective when started early after acetaminophen ingestion.

Question 46Pharmaceutical Agents, Drugs of Abuse, and Alcohols

Which drug class is first-line for alcohol withdrawal seizures?

  1. Benzodiazepines Correct answer.
  2. Antipsychotics
  3. Gabapentinoids
  4. Beta blockers

Explanation

Benzodiazepines are first-line because they enhance GABA-A activity and reduce withdrawal-related neuronal excitability. They also treat autonomic hyperactivity and prevent progression to delirium tremens.

Question 47Pharmaceutical Agents, Drugs of Abuse, and Alcohols

Which agent is preferred for severe agitation and seizures caused by cocaine toxicity?

  1. Haloperidol
  2. Flumazenil
  3. Propranolol
  4. Benzodiazepines Correct answer.

Explanation

Benzodiazepines are preferred for cocaine-induced agitation, seizures, and sympathomimetic toxicity. They reduce CNS excitation and counteract cocaine's stimulant effects.

Question 48Pharmaceutical Agents, Drugs of Abuse, and Alcohols

Disulfiram produces acetaldehyde accumulation by inhibiting which enzyme?

  1. Aldehyde dehydrogenase Correct answer.
  2. Cytochrome P450 2E1
  3. Monoamine oxidase
  4. Alcohol dehydrogenase

Explanation

Disulfiram inhibits aldehyde dehydrogenase, preventing conversion of acetaldehyde to acetate. Alcohol ingestion then causes acetaldehyde accumulation with flushing, vomiting, and tachycardia.

Question 49Pharmaceutical Agents, Drugs of Abuse, and Alcohols

Which finding is an indication for hemodialysis in methanol poisoning?

  1. Normal visual acuity
  2. Age greater than 60 years
  3. Severe metabolic acidosis refractory to bicarbonate Correct answer.
  4. Serum methanol concentration of 10 mg/dL

Explanation

Hemodialysis is indicated for severe methanol poisoning, including refractory metabolic acidosis, visual symptoms, renal failure, or very high methanol levels. It removes methanol and toxic metabolites.

Question 50Pharmaceutical Agents, Drugs of Abuse, and Alcohols

Which vitamin is given to promote conversion of glyoxylate to glycine in ethylene glycol poisoning?

  1. Thiamine
  2. Cyanocobalamin
  3. Vitamin K
  4. Pyridoxine Correct answer.

Explanation

Pyridoxine is a cofactor that shunts glyoxylate toward glycine, reducing oxalate formation. Thiamine is also sometimes given to promote an alternative metabolic pathway.