1. The potential drug-drug interaction of terfenadine and tedisamil has been investigated. Terfenadine is a widely used antihistamine drug with the potential for QTC prolongation. Tedisamil is a potassium channel blocking agent known to produce bradycardia and prolong the effective refractory period in man. 2. Tedisamil and terfenadine were incubated with human liver microsomes for 30 min at 37...

Terfenadine is a second generation histamine receptor antagonist which is widely used as a non‑sedating antihistamine to relieve allergic responses. However, terfenadine has been associated with a number of side effects on cardiac electrical activities through blocking multiple ion channels in the heart, particularly K+ channels. Previous studies have also implied that terfenadine may have a po...

We previously reported that the histamine H1 receptor antagonist terfenadine enhances the excitotoxic response to N-methyl-D-aspartate (NMDA) receptor agonists in cerebellar neurons. Here we investigated whether this unexpected action of terfenadine relates to its antihistamine activity, and which specific events in the signal cascade coupled to NMDA receptors are affected by terfenadine. Low c...

Terfenadine and ketoconazole are the most widely used positive reference agents in non-clinical cardiac repolarization safety studies. The aim of the present study was to evaluate the effects of terfenadine, ketoconazole and their combination on QT prolongation using conscious guinea pigs. Conscious telemetered guinea pigs were orally administered terfenadine (50 mg/kg), ketoconazole (200 mg/kg...

BACKGROUND AND OBJECTIVES Dilated cardiomyopathy can be the end-stage of severe cardiac disorders and directly affects the cardiac muscle, inducing cardiomegaly and heart failure (HF). Although a wide variety of animal models are available to study dilated cardiomyopathy, there is no model to assess dilated cardiomyopathy with non-invasive, simple, and large screening methods. METHODS We deve...

Since the introduction of our local manufacturing of terfenadine, we have observed and expressed our concern about a small but increasing number of serious ventricular arrhythmias associated with the use of this non sedating antihistamine. In January 1997 a case of torsade de pointes ventricular tachycardia was detected in a previously healthy woman taking terfenadine with erythromycin. El...

The effects of terfenadine, an antiallergic drug also known for its QT-prolonging and arrhythmogenic activities, on the action potential of isolated myocardial tissue preparations from rabbits were examined with microelectrode techniques. In the Purkinje fibers and atrium, terfenadine concentration dependently decreased the maximum rate of rise (+.V(max)) without affecting other action potentia...

In a study designed to determine the protective effect of the specific histamine H1 antagonist terfenadine on hypertonic saline induced bronchoconstriction, 10 asthmatic subjects underwent hypertonic saline challenge (3.6%) after premedication with placebo or terfenadine (120 mg) 12 and two hours before the challenge. Hypertonic saline was administered in a dose dependent manner and the respons...

The hepatobiliary disposition of xenobiotics may involve passive and/or active uptake, metabolism by cytochromes P450, and excretion of the parent compound and/or metabolite(s) into bile. Although in vitro systems have been used to evaluate these individual processes discretely, mechanistic in vitro studies of the sequential processes of uptake, metabolism, and biliary or basolateral excretion ...

Inhaled adenosine 5'-monophosphate (AMP) causes bronchoconstriction in atopic asthma, probably after in vivo conversion to adenosine. It has been suggested that adenosine potentiates preformed mediator release from mast cells on the mucosal surface of the airways by interacting with specific purinoceptors, without affecting the release of newly generated mediators. The airway response of nine n...