Agent nonsedating antihistamine
This adverse effect is linked to their effect on potassium channels leading to slowing of repolarization rate.
They were withdrawn from the market because they could induce ventricular arrhrythmias, prolongation of QT interval which can lead to torsades de pointes.
They have a longer duration of action and longer plasma half-life than the first generationdrugs, which makes it possible to reduce the number of daily intakes.
They do not have, in normal dose, antimuscarinic effect, except mequitazine which has a mild antimuscarinic effect.
Ceterizine is a racemic; one of its isomers called levocetirizine is also released on the market.
Mizolastine does not induce, in usual dosage, prolongation of QT interval; however its combination with macrolides and imidazol antifungal agents is disadvised because of a possible inhibition of its catabolism.