Perioperative nonspecific histamine release: a new classification by aetiological mechanisms and evaluation of their clinical relevance

The antiarrhythmic properties of quifenadine, H1-histamine receptor blocker in children with premature beats: a randomized controlled pilot trial

Despite evolving success of mini-invasive techniques in treating cardiac arrhythmias in children, pharmaceuticals remain the cornerstone therapeutic option. Beyond conventional antiarrhythmic agents such as amiodarone, local anesthetics, tranquilizers, anticonvulsants, and neuroleptics exhibit antiarrhythmic properties. H(1)-histamine receptor blockers are widely used in treating allergies in children. Observational studies suggest efficacy of these agents for treating or preventing tachyarrhythmias, although prolongation of QT interval, and ventricular arrhythmias occur. We determined safety and efficacy of antihistamine, quifenadine, versus conventional amiodarone on cardiac rhythm in children with frequent premature beats (PB). One hundred and four patients (mean age 10.8 +/- 3.2 years) with ventricular (n = 65), supraventricular (n = 39) PB were randomized 1:1 to quifenadine (2 mg kg(-1) day(-1); n = 54), or amiodarone (9 mg kg(-1) day(-1), n = 50) arms. Both groups were treated for 2 weeks. All patients underwent 24-hour Holter monitoring 3 times: before at 14-28 days after randomization, and during the follow up at 2-3 months. The mean frequency of PB in quifenadine group was 562 +/- 61 per hour and 597 +/- 78 per hour in the amiodarone-treated children. Full antiarrhythmic efficacy (PB < 75% from baseline) has been achieved in 23/54 (43%) of quifenadine-treated patients, which was less than after amiodarone treatment (37/50, 74%, P = 0.02). Quifenadine was mostly beneficial in children with supraventricular PB and/or bradycardia than in those with ventricular PB; it was associated with a trend toward increased heart rate during day (88.5 +/- 8.4 beats/min) and night (67.3 +/- 6.2) compared with amiodarone (79.6 +/- 7.8 and 56.1 +/- 5.7 beats/min, respectively; P = 0.04). The incidence of side effects in quifenadine group (drowsiness and headache) was low (2%) in contrast to the alarming 40% risk associated with amiodarone therapy. Quifanidine exhibits antiarrhythmic activity in children with frequent PB, without significant QT prolongation, or sinus node depression. Although, H(1)-histamine receptor blocker is less potent than amiodarone, much better safety profile of quifenadine is advantageous, especially in children. Future large trials with proving novel antihistamines pleiotropy are warranted.

Intravenous morphine and nalbuphine increase histamine and catecholamine release without accompanying hemodynamic changes

Patients receiving intravenous morphine at doses of 0.3 and 1.0 mg/kg for general anesthesia have been reported to show significant elevations in plasma histamine that are associated with hemodynamic changes. We undertook a prospective, randomized, double-blind trial in which 0.15 mg/kg morphine or 0.3 mg/kg nalbuphine was administered intravenously to normal volunteers. Thirteen of 15 subjects receiving morphine and 10 of 14 subjects receiving nalbuphine had elevations in plasma histamine levels and symptoms of histamine release within 5 minutes of drug administration. Six subjects in the morphine group and five in the nalbuphine group exhibited levels of plasma histamine > 2.0 ng/ml, but these levels were not associated with hemodynamic changes and occurred 10 to 15 minutes after drug administration. Our study suggests that the opiate-induced elevation of plasma histamine derives from cutaneous mast cells.