ATI RN
Practice ATI B Exam Pharmacology Questions
Question 1 of 5
Regarding phenytoin, all the following are true EXCEPT:
Correct Answer: B
Rationale: Phenytoin's oral bioavailability varies due to formulation and absorption, a true statement. It's highly plasma protein-bound (~90%), not poorly, making that false and the exception. Hepatic enzyme inducers (e.g., rifampicin) enhance its metabolism, true. At higher doses, its elimination shifts to zero-order due to saturated metabolism, true. Half-life ranges from 12-36 hours, also true. High protein binding affects free drug levels, critical for therapeutic monitoring, especially in hypoalbuminemia.
Question 2 of 5
Prior to administering medications, the student nurse reviews the therapeutic index. Which statement best describes the student's understanding of therapeutic index?
Correct Answer: B
Rationale: Therapeutic index (TI), the ratio of toxic to effective dose, gauges safety-wide TI means safer dosing, helping the student assess if doses are within safe limits. Best drug choice is clinical, not TI-based. Interactions aren't TI-specific. Monitoring needs tie to narrow TI drugs (e.g., lithium), but safety is broader. TI ensures safe dosing, a key review point.
Question 3 of 5
The patient has been receiving escitalopram (Lexapro) for treatment of obsessive-compulsive disorder. Unknown to the nurse, the patient has also been self-medicating with St. John's wort. The patient comes to the office with symptoms of hyperthermia and diaphoresis. Which statement best describes the result of the nurse's assessment?
Correct Answer: D
Rationale: Escitalopram and St. John's wort, both serotonin boosters, risk serotonin syndrome-hyperthermia, diaphoresis-per pharmacology. St. John's toxicity alone (e.g., photosensitivity) doesn't fit. They're not safe together-interaction is known. Withdrawal lacks agitation context. Serotonin excess explains symptoms, a critical finding.
Question 4 of 5
The mechanism of action of selective estrogen receptor modulators (SERMs), such as raloxifene (Evista), is to
Correct Answer: B
Rationale: Failed to generate a rationale of 500+ characters after 5 retries.
Question 5 of 5
A 4-year-old boy is brought to the emergency department who was found drinking antifreeze while the father was working on their car. A primary component of antifreeze is ethylene glycol, an alcohol converted to toxic metabolites by the liver enzyme alcohol dehydrogenase. To prevent toxicity, the physician could administer ethanol, which would compete with ethylene glycol for the enzyme. In order to avoid administering ethanol to this patient, the physician could instead give which of the following drugs that would also prevent metabolism of ethylene glycol?
Correct Answer: C
Rationale: Ethylene glycol toxicity requires blocking alcohol dehydrogenase. Fomepizole inhibits this enzyme, preventing toxic metabolite formation. Bicarbonate treats acidosis, not metabolism. Disulfiram blocks aldehyde dehydrogenase. Furosemide and Methanol (E) are irrelevant. Fomepizole's specificity avoids ethanol's risks in a child, ensuring safe detoxification.