Answer to Question 1
ANS: C
Arrhythmias usually appear with excessive antihistamine dosages but have been reported with concurrent use of macrolide antibiotics (e.g., erythromycin, clarithromycin), imidazole antifungals (e.g., itraconazole, ketoconazole), and other drugs that inhibit the cytochrome CYP450 system, as well as in patients with severe hepatic disease. Accordingly, histamine1 (H1) antagonists are relatively contraindicated for use in patients with liver disease or those who may be receiving macrolide antibiotics or imidazole antifungal drugs.
Answer to Question 2
ANS: D
Drowsiness is more common with first-generation histamine1 (H1) antagonists than with sec-ond-generation drugs and is characterized by slowed reaction times, diminished alertness, and drowsiness in 20 of patients. Impaired performance occurs whether or not the patient feels drowsy. This is particularly of concern in older adults, who are at high risk for falls. Fortunately, tolerance to the sedative effect of H1 antagonists often develops within a few days or weeks.