The PMHNP is treating a 69-year-old man with ziprasidone (Geodon) for schizophrenia and orders an electrocardiogram. Which QTc interval places the patient at greatest risk for torsades de pointes?
100–200 milliseconds
300–400 milliseconds
500–700 milliseconds
260–460 milliseconds
The Correct Answer is C
Choice A reason: A QTc interval of 100–200 milliseconds is abnormally short and not typically associated with torsades de pointes. While short QT syndrome is a separate arrhythmogenic condition, torsades is linked to prolonged QTc intervals.
Choice B reason: A QTc interval of 300–400 milliseconds is within the normal range for most adults. This range does not pose a significant risk for torsades de pointes unless accompanied by other risk factors or medications.
Choice C reason: A QTc interval of 500–700 milliseconds is markedly prolonged and significantly increases the risk for torsades de pointes, a potentially life-threatening polymorphic ventricular tachycardia. Ziprasidone is known to prolong the QT interval, and monitoring is essential to prevent arrhythmias.
Choice D reason: A QTc interval of 260–460 milliseconds includes both low-normal and upper-normal values. While the upper end may warrant caution, especially in patients on QT-prolonging drugs, it does not represent the highest risk range for torsades.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is B
Explanation
Choice A reason: Metronidazole has shown efficacy in treating perianal Crohn’s disease and mild-to-moderate disease activity, particularly when infection or abscess is suspected. It is often used as adjunct therapy.
Choice B reason: Sulfasalazine is more effective in ulcerative colitis than in Crohn’s disease. Its benefit in Crohn’s is limited and not considered first-line, especially for small bowel involvement. This makes the statement incorrect.
Choice C reason: Thiopurines such as azathioprine and 6-mercaptopurine are immunomodulators used to maintain remission and reduce steroid dependence. They are effective in long-term management of Crohn’s disease.
Choice D reason: NSAIDs can exacerbate Crohn’s disease by increasing intestinal permeability and promoting inflammation. Their use is generally avoided in patients with inflammatory bowel disease.
Correct Answer is D
Explanation
Choice A reason: Insulin resistance is the hallmark of type 2 diabetes mellitus, not type 1. In type 1 diabetes, the issue is not resistance to insulin but rather a lack of insulin production due to destruction of beta cells.
Choice B reason: Type 1 diabetes is not caused by a single genetic mutation nor is it inherited in an autosomal dominant fashion. While genetic predisposition plays a role, it involves multiple genes and environmental triggers leading to autoimmune destruction.
Choice C reason: Secondary diabetes can result from pancreatic diseases, hormonal disorders, or medications, but this is classified as type 3c diabetes or drug-induced diabetes. It is not the mechanism underlying classic type 1 diabetes.
Choice D reason: Type 1 diabetes is an autoimmune condition where the immune system mistakenly attacks and destroys insulin-producing beta cells in the pancreas. This leads to absolute insulin deficiency, hyperglycemia, and in severe cases, diabetic ketoacidosis.
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