NAPLEX (North American Pharmacist Licensure Examination) Practice Exam

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Ace your North American Pharmacist Licensure Examination (NAPLEX) with our comprehensive practice test. Features include interactive flashcards, multiple-choice questions, with detailed hints and explanations. Fast-track your pharmacy career today!

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Which medication group is associated with a markedly prolonged QT interval when it is greater than 500 ms?

Antihypertensives
Antiarrhythmics
Antidiabetics
Antibiotics

The correct answer is: Antiarrhythmics

Antiarrhythmics are the correct choice as the medication group associated with a markedly prolonged QT interval when it is greater than 500 ms. Antiarrhythmic medications, especially those belonging to class III (e.g., amiodarone, sotalol), are commonly known for their potential to prolong the QT interval on an electrocardiogram (ECG). Prolongation of the QT interval can predispose patients to a type of arrhythmia known as Torsades de Pointes, which can be life-threatening. Monitoring the QT interval and adjusting medication regimens accordingly is crucial in patients taking antiarrhythmic drugs to prevent adverse cardiac events. Antihypertensives, antidiabetics, and antibiotics are not typically associated with marked QT prolongation as compared to antiarrhythmic medications. While some medications from these groups may have a mild effect on the QT interval, the risk is significantly higher with antiarrhythmics.