Influence of promethazine on cardiac repolarisation: a double‐blind, midazolam‐controlled study

Abstract

Drugs used in anaesthesia may provoke torsadogenic changes in cardiac repolarisation. The aim of this study was to assess the effect of promethazine on the parameters of ventricular repolarisation: QTc interval and transmural dispersion of repolarisation. Forty patients were randomly allocated to receive promethazine (25 mg) or midazolam (2.5 mg). Changes in the ECG and arterial blood pressure were recorded. Correction of QT interval was calculated using Bazett's formula and Fridericia's correction; transmural dispersion of repolarisation was determined as T(peak)-T(end) time. Significant prolongation of QT interval, corrected with both formulae, was detected in patients receiving promethazine, while no change in the QTc value was observed in the midazolam group. There were no significant differences in T(peak)-T(end) time either between or within the groups. In conclusion, promethazine induces significant QTc prolongation but the lack of influence on transmural dispersion of repolarisation makes the risk of its torsadogenic action very low.

Effects of balanced propofol sedation on QT, corrected QT, and P-wave dispersion on upper endoscopy

“…Midazolam is used in endoscopic sedation and is known to not affect the QTc interval (19). In one study, Owczuk et al (20) reported that propofol infusion decreased Pwd after 3 and 5 min of anesthesia.…”

Promethazine use among chronic pain patients

“…Consuming large quantities of these two drugs prolongs and intensifies each drug’s sedative effects and is also responsible for an increase in life-threatening events, such as delirium, respiratory depression, overdose, neuroleptic malignant syndrome, and prolongation of the QT interval (Owczuk et al, 2009; Jo et al, 2009, Gerostamoulos et al, 1996; Mattoo et al, 1997). In contemporary medical practice, the use of the two drugs in combination for sedation has declined due to these adverse effects and lack of data supporting clinical efficacy (Richter and Burk, 1992).…”

Current advances in treatment of gastroparesis

“…They exert their anti-emetic effects via histamine H1 receptor antagonism. The main agent in this class, promethazine (Phenergan), is used commonly despite concerns over sedation, potential cardiac toxicity (QTc prolongation), and administration site soft tissue damage [1,65]. Efficacy studies in patients with gastroparesis are lacking but one 2011 study of emergency room patients with nausea and/or vomiting found no difference in efficacy in nausea relief between promethazine, metoclopramide and ondansetron [66].…”

“…These samples have revealed that nearly all patients with gastroparesis have commonly identified cellular changes ( Table 3). The two most common findings are loss or dysfunction of the Interstitial Cells of Cajal (ICC) (the 'gastric pacemaker cell') followed by an intense inflammatory infiltration predominated by macrophages [65,97,98]. Other commonly seen changes include loss of neuronal nitric oxide synthase (nNOS), decrease in nerve fibers/neurons and fibrosis.…”