ATI RN
Practice ATI B Exam Pharmacology Questions
Question 1 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 2 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 3 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.
Question 4 of 5
A 6-year-old boy is brought to his primary care physician with a history of hay fever and asthma. He usually has two to three attacks per week. For symptom control, he uses an albuterol inhaler, but his parents would like to try something more. They would like him to take something that would lessen the amount of attacks he has. Although corticosteroids would probably work best for prophylaxis, they are contraindicated in children. He is instead given montelukast. How does montelukast work?
Correct Answer: A
Rationale: Montelukast prevents asthma attacks by blocking leukotriene receptors . Leukotrienes drive inflammation; montelukast reduces this, complementing albuterol's acute relief. Muscarinic blockade is ipratropium's action. COX inhibition (C, D) is NSAIDs'. Lipoxygenase inhibition (E) is zileuton's. Montelukast's specificity suits prophylaxis in this child.
Question 5 of 5
A patient comes to the ER with a painful stab wound. The ER resident administers pentazocine for the pain. Soon after administration the patient experiences sweating, restlessness, and an increase in pain sensations. What is the most likely explanation for his symptoms?
Correct Answer: B
Rationale: Pentazocine, a mixed opioid agonist-antagonist, acts as a kappa receptor agonist and a partial mu receptor agonist, providing analgesia in opioid-naive patients. However, in a heroin addict with high mu receptor tolerance, pentazocine's partial antagonism at mu receptors can displace full agonists like heroin, precipitating withdrawal symptoms—sweating, restlessness, and heightened pain perception. Tolerance to pentazocine itself wouldn't typically increase pain; it would reduce efficacy. Pentazocine is an effective analgesic in appropriate contexts, so ineffectiveness isn't the issue. Incorrect dosing might alter efficacy or toxicity but wouldn't specifically cause this withdrawal-like reaction. The patient's history of heroin use explains this response, as pentazocine's antagonist properties disrupt the opioid equilibrium, unmasking withdrawal in a dependent individual.