What body system will the nurse assess for common adverse effects of traditional antihistamines?
Respiratory
Central nervous
Cardiovascular
Gastrointestinal
The Correct Answer is B
Choice A reason: Respiratory effects are not primary adverse effects of traditional antihistamines like diphenhydramine. They relieve respiratory symptoms (e.g., allergic rhinitis) by blocking histamine H1 receptors. Adverse effects primarily involve the central nervous system, like sedation, due to their ability to cross the blood-brain barrier.
Choice B reason: Traditional antihistamines, such as diphenhydramine, commonly cause central nervous system effects like drowsiness, confusion, or impaired coordination. By blocking H1 receptors in the brain, they disrupt histamine’s wakefulness-promoting effects, leading to sedation, making this the primary system to assess for adverse effects.
Choice C reason: Cardiovascular effects, like tachycardia, are rare with traditional antihistamines and more associated with second-generation antihistamines in overdose. First-generation antihistamines primarily cause CNS and anticholinergic effects, not significant cardiovascular disturbances, making this a less critical system to monitor.
Choice D reason: Gastrointestinal effects, like nausea, are less common with traditional antihistamines compared to CNS effects. Their anticholinergic properties may cause dry mouth or constipation, but sedation and cognitive impairment are more prominent, making the central nervous system the primary focus for adverse effect assessment.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is B
Explanation
Choice A reason: Valerian, used for sleep disorders, has no significant interaction with anticoagulants like warfarin. It may cause sedation but does not affect hepatic CYP450 enzymes or vitamin K-dependent clotting factors, making it safe for patients on anticoagulant therapy, with no impact on bleeding risk or drug metabolism.
Choice B reason: St. John’s wort induces hepatic CYP450 enzymes, particularly CYP3A4, accelerating warfarin metabolism. This reduces warfarin’s anticoagulant effect, decreasing INR and increasing thrombosis risk. Patients must avoid it to maintain therapeutic anticoagulation, making this a critical herbal interaction to report.
Choice C reason: Saw palmetto, used for prostate health, has minimal interaction with anticoagulants. It does not significantly affect CYP450 enzymes or clotting factor synthesis. While it may have mild antiplatelet effects, it is not a primary concern for warfarin therapy compared to St. John’s wort’s enzyme induction.
Choice D reason: Soy has no significant interaction with anticoagulants like warfarin. It does not affect hepatic metabolism or vitamin K-dependent clotting factors. While dietary vitamin K can influence warfarin, soy’s impact is minimal, making it less critical to avoid compared to enzyme inducers like St. John’s wort.
Correct Answer is A
Explanation
Choice A reason: Fluconazole inhibits hepatic CYP2C9, which metabolizes warfarin, increasing warfarin’s plasma levels. This enhances its anticoagulant effect, inhibiting vitamin K-dependent clotting factors, leading to a higher risk of bleeding. Monitoring INR and bleeding signs is critical to prevent hemorrhage in patients on this combination.
Choice B reason: Warfarin does not decrease fluconazole’s antifungal efficacy. Fluconazole inhibits fungal ergosterol synthesis, and its action is unaffected by warfarin’s anticoagulant mechanism. The primary interaction is fluconazole’s effect on warfarin metabolism, not a reduction in fluconazole’s ability to treat fungal infections.
Choice C reason: Fluconazole increases, not reduces, warfarin’s anticoagulant effect by inhibiting CYP2C9, slowing warfarin metabolism. This leads to elevated warfarin levels, prolonging INR and increasing bleeding risk. Reduced anticoagulant action would occur with enzyme inducers, not inhibitors like fluconazole.
Choice D reason: Hypokalemia is not a known interaction between fluconazole and warfarin. Fluconazole’s side effects include hepatotoxicity, and warfarin affects clotting, but neither significantly alters potassium levels. Electrolyte imbalances are more associated with diuretics or amphotericin B, not this drug combination.
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