Intervallo QT lungo
Reazione avversa da farmaco (ADR)
|Aumento della creatinina nel sangue|
Varianti ✨Per l'analisi computazionale dettagliata delle varianti, si prega di selezionare l'abbonamento standard a pagamento.
Informazioni dei farmaci per i pazienti
Non abbiamo ulteriori avvertenze per la co-somministrazione di astemizolo e dronedarone. Si prega di consultare le informazioni specialistiche pertinenti.
I cambiamenti riportati in seguito all'esposizione corrispondono ai cambiamenti nell'area sottesa alla curva concentrazione plasmatica-tempo [ AUC ]. Non è stato possibile rilevare nessun tipo di cambiamento nell'esposizione alla astemizolo. Allo stato attuale non è possibile valutare come influisce la dronedarone. Non è stato possibile rilevare nessun tipo di cambiamento nell'esposizione alla dronedarone. Allo stato attuale non è possibile valutare come influisce la astemizolo.
I parametri farmacocinetici della popolazione media sono utilizzati come punto di partenza per calcolare i cambiamenti del singolo individuo esposto alle interazioni farmacologiche
La astemizolo ha una bassa biodisponibilità [ F ] orale, perciò nel corso di un interazione farmacologica la concentrazione plasmatica massima (Cmax) tende fortemente a cambiare. L'emivita [ t12 ] del farmaco è di 22 ore e la concentrazione allo stato stazionario [Css] si raggiunge dopo circa 88 ore. Il legame proteico [ Pb ] è forte al 97%. Tra l'altro, il metabolismo avviene rispettivamente attraverso gli enzimi CYP2D6 e CYP3A4..
La dronedarone ha una bassa biodisponibilità [ F ] orale, perciò nel corso di un interazione farmacologica la concentrazione plasmatica massima (Cmax) tende fortemente a cambiare. L'emivita [ t12 ] del farmaco è di 16 ore e la concentrazione allo stato stazionario [Css] si raggiunge dopo circa 64 ore. Il legame proteico [ Pb ] è molto forte al 98.1% e il volume di distribuzione [ Vd ] è molto grande in 1400 litri. Il metabolismo avviene principalmente attraverso l'enzima CYP3A4 e il trasporto attivo avviene in particolare attraverso i trasportatori PGP e TRA8X8.
|Effetti serotoninergici a||0||Ø||Ø|
Valutazione: Sulla base dei dati a nostra disposizione, né la astemizolo né la dronedarone potenziano l'attività serotoninergica.
|Kiesel & Durán b||0||Ø||Ø|
Valutazione: Sulla base dei dati a nostra disposizione, né la astemizolo né la dronedarone causano un aumento dell'attività anticolinergica.
Intervallo QT lungo
Valutazione: La co-somministrazione di astemizolo e dronedarone potrebbe causare tachicardia ventricolare a torsione di punta.
Effetti collaterali generali
|Effetti collaterali||∑ frequenza||ast||dro|
|Aumento della creatinina nel sangue||51.0 %||n.a.||51.0|
|Dolore addominale||4.0 %||n.a.||4.0|
|Reazioni allergiche della pelle||1.0 %||n.a.||+|
|Insufficienza cardiaca||0.0 %||n.a.||0.01|
Insufficienza epatica: dronedarone
Insufficienza renale: dronedarone
Malattia polmonare interstiziale: dronedarone
Abbiamo valutato il rischio individuale di effetti indesiderati in base alle risposte fornite ed alle informazioni scientifiche disponibili. Le informazioni contenute nel sito hanno esclusivamente scopo informativo e non sostituiscono il parere del medico. Si accomanda pertanto di chiedere sempre il parere del proprio medico curante e/o di specialisti riguardo qualsiasi indicazione riportata. Nella versione alpha test, il rischio di tutti i farmaci non è stato ancora completamente valutato.
Abstract: Astemizole is a long-acting, highly selective histamine1-receptor antagonist with minimal central and anticholinergic effects. Comparison studies have shown astemizole to be equal or superior to currently available antihistamines, beclomethasone nasal spray, and cromolyn sodium in relieving allergic symptoms of seasonal and perennial allergic rhinitis. Other uses include treatment of allergic conjunctivitis and chronic urticaria. Astemizole is not as effective for treatment of acute allergic symptoms because of its delayed onset of action. Astemizole and its active metabolite, desmethylastemizole, have long elimination half-lives permitting once-daily dosing. The incidence of sedation is lower than with conventional antihistamines, but increased appetite and weight gain do occur. Astemizole should be useful for both maintenance and prophylactic therapy in patients with chronic allergic conditions who cannot tolerate the sedative or anticholinergic effects of conventional antihistamines.
Abstract: Astemizole is an H1-histamine receptor antagonist with a long duration of action permitting once daily administration. Its efficacy in seasonal and perennial allergic rhinitis has been convincingly demonstrated, and several comparative studies suggest that astemizole is at least as effective as some other H1-histamine receptor antagonists. A few smaller studies have shown beneficial effects on the symptoms of allergic conjunctivitis and chronic urticaria (but not atopic dermatitis). While astemizole appears to share with other H1-histamine receptor antagonists a tendency to increase appetite and cause weight gain after prolonged use, it offers the important advantage of an absence of significant central nervous system depression or anticholinergic effects with usual doses. Thus, astemizole offers a worthwhile improvement in side effect profile over 'traditional' H1-histamine receptor antagonists, especially in patients bothered by the sedative effects of these drugs.
Abstract: An overdose of astemizole predisposes the myocardium to ventricular dysrhythmias, including torsades de pointes. Herein we describe a case of astemizole-induced torsades de pointes ventricular tachycardia and also review previous case reports in the literature. All the patients were young, and dysrhythmias developed only in those with corrected QT intervals greater than 500 ms. Although several mechanisms have been postulated, no clear explanation has been provided for why astemizole promotes myocardial dysrhythmias. Treatment of astemizole-induced torsades de pointes includes discontinuing use of astemizole, intravenous administration of magnesium sulfate and isoproterenol, temporary cardiac pacing, and, when necessary, direct current cardioversion. A cardiac cause of syncope or convulsions must not be overlooked, especially in patients taking H1 antagonists because they often have these symptoms before hospitalization or detection of torsades de pointes (or both).
Abstract: No Abstract available
Abstract: A 26 year-old woman was admitted to the hospital two hours after astemizole overdose. Electrocardiograph showed a prolonged QT interval. Torsade de pointes occurred 13 h after ingestion. Plasma levels of astemizole plus hydroxylated metabolites showed an apparent plasma half-life of 17 h. The possible occurrence of torsade de pointes in astemizole overdose, and the long elimination time of astemizole and hydroxylated metabolites, makes it necessary to maintain ECG monitoring until QT interval has returned to normal.
Abstract: AIMS: The aim of this study was to investigate the influence of chronic itraconazole treatment on the pharmacokinetics and cardiovascular effects of single dose astemizole in healthy subjects was studied. METHODS: Twelve male volunteers were taking orally 200 mg twice daily itraconazole or placebo for 14 days with a washout period of 4 weeks in between. Approximately 2 h after the morning dose of itraconazole or placebo on day 11, 10 mg astemizole was orally administered. The plasma concentrations of astemizole and desmethylastemizole were measured by radioimmunoassay up to 504 h after administration; electrocardiograms with analysis of the QTc interval were recorded up to 24 h post administration. RESULTS: Itraconazole treatment did not significantly change the peak concentration of astemizole (0.74 vs 0.81 ng ml-1) but it increased the area under the curve from 0 to 24 h (5.46 to 9.95 ng ml-1 h) and from 0 to infinity (17.4 to 48.2 ng ml-1 h), and the elimination half-life (2.1 to 3.6 days). The systemic bioavailability of desmethylastemizole was also increased. The QTc interval did not increase after astemizole administration and there was no difference in the QTc intervals between the itraconazole and placebo session. CONCLUSIONS: Chronic administration of itraconazole influences the metabolism of single dose astemizole in normal volunteers without changes of cardiac repolarization during the first 24 h after astemizole administration. However, the reduction in astemizole clearance under concomitant administration of itraconazole may result in a marked increase in astemizole plasma concentrations and QTc alterations during chronic combined intake of astemizole with itraconazole.
Abstract: Second-generation histamine H1 receptor antagonists (antihistamines) have been developed to reduce or eliminate the sedation and anticholinergic adverse effects that occur with older H1 receptor antagonists. This article evaluates second-generation antihistamines, including acrivastine, astemizole, azelastine, cetirizine, ebastine, fexofenadine, ketotifen, loratadine, mizolastine and terfenadine, for significant features that affect choice. In addition to their primary mechanism of antagonising histamine at the H1 receptor, these agents may act on other mediators of the allergic reaction. However, the clinical significance of activity beyond that mediated by histamine H1 receptor antagonism has yet to be demonstrated. Most of the agents reviewed are metabolised by the liver to active metabolites that play a significant role in their effect. Conditions that result in accumulation of astemizole, ebastine and terfenadine may prolong the QT interval and result in torsade de pointes. The remaining agents reviewed do not appear to have this risk. For allergic rhinitis, all agents are effective and the choice should be based on other factors. For urticaria, cetirizine and mizolastine demonstrate superior suppression of wheal and flare at the dosages recommended by the manufacturer. For atopic dermatitis, as adjunctive therapy to reduce pruritus, cetirizine, ketotifen and loratadine demonstrate efficacy. Although current evidence does not suggest a primary role for these agents in the management of asthma, it does support their use for asthmatic patients when there is coexisting allergic rhinitis, dermatitis or urticaria.
Abstract: AIMS: The aims of the present study were to investigate the metabolism of astemizole in human liver microsomes, to assess possible pharmacokinetic drug-interactions with astemizole and to compare its metabolism with terfenadine, a typical H1 receptor antagonist known to be metabolized predominantly by CYP3A4. METHODS: Astemizole or terfenadine were incubated with human liver microsomes or recombinant cytochromes P450 in the absence or presence of chemical inhibitors and antibodies. RESULTS: Troleandomycin, a CYP3A4 inhibitor, markedly reduced the oxidation of terfenadine (26% of controls) in human liver microsomes, but showed only a marginal inhibition on the oxidation of astemizole (81% of controls). Three metabolites of astemizole were detected in a liver microsomal system, i.e. desmethylastemizole (DES-AST), 6-hydroxyastemizole (6OH-AST) and norastemizole (NOR-AST) at the ratio of 7.4 : 2.8 : 1. Experiments with recombinant P450s and antibodies indicate a negligible role for CYP3A4 on the main metabolic route of astemizole, i.e. formation of DES-AST, although CYP3A4 may mediate the relatively minor metabolic routes to 6OH-AST and NOR-AST. Recombinant CYP2D6 catalysed the formation of 6OH-AST and DES-AST. Studies with human liver microsomes, however, suggest a major role for a mono P450 in DES-AST formation. CONCLUSIONS: In contrast to terfenadine, a minor role for CYP3A4 and involvement of multiple P450 isozymes are suggested in the metabolism of astemizole. These differences in P450 isozymes involved in the metabolism of astemizole and terfenadine may associate with distinct pharmacokinetic influences observed with coadministration of drugs metabolized by CYP3A4.
Abstract: BACKGROUND: Amiodarone is an effective antiarrhythmic drug rarely associated with torsade de pointes arrhythmias (TdP). The noniodinated compound dronedarone could resemble amiodarone and be devoid of the adverse effects. In the dog with chronic complete atrioventricular (AV) block (CAVB) and acquired long-QT syndrome, the electrophysiological and proarrhythmic properties of the drugs were compared after 4 weeks of oral treatment. METHODS AND RESULTS: Amiodarone (n=7, 40 mg. kg(-1). d(-1)) and dronedarone (n=8, 20 mg/kg BID) were started at 6 weeks of CAVB (baseline). Six dogs served as controls. Surface ECGs and endocardially placed monophasic action potential catheters in the left (LV) and right (RV) ventricles were recorded to assess QTc time, action potential duration (APD), interventricular dispersion (DeltaAPD=LV APD minus RV APD), early afterdepolarizations (EADs), ectopic beats, and TdP. Both amiodarone (+21%) and dronedarone (+31%) increased QTc time. Amiodarone showed no increase in DeltaAPD in 4 of 7 dogs, whereas dronedarone augmented DeltaAPD in 7 of 8 animals. After dronedarone, TdP occurred in 4 of 8 dogs with the highest DeltaAPD (105+/-20 ms). TdP was never seen with amiodarone, not even in the dogs that had DeltaAPD values comparable to those with dronedarone. Furthermore, a difference existed in EADs and ectopic activity incidence (dronedarone 3 of 8; amiodarone 0 of 7), which was also seen during an epinephrine challenge. CONCLUSIONS: In the CAVB dog model, both amiodarone and dronedarone prolong QT time (class III effect). The absence of TdP with amiodarone seems to be related to homogeneous APD lengthening in the majority of dogs and the lack of EADs and/or ventricular ectopic beats in all.
Abstract: Dronedarone, a non-iodinated benzofuran derivative, was developed as a potentially less toxic alternative to amiodarone. This study describes Holter data of dronedarone in humans. Five groups of healthy subjects were given 1 of 5 oral doses of dronedarone in a twice-daily regimen or placebo. Holter recordings of circadian rhythmicity of RR and QT intervals were evaluated. Dronedarone prolonged RR and QT intervals as a function of dose, without effect on circadian patterns. The relative prolongation of QT, QTc, and RR by dronedarone was significant. The QTc interval did not exhibit a clearly recognizable circadian pattern, suggesting that the circadian pattern of the QT interval was mostly a reflection of circadian changes in the RR interval in the study population. Dronedarone resembled amiodarone in class III and sympatholytic effects, indicating its potential as a unique antiarrhythmic compound seemingly devoid of the side effects mediated by iodine in amiodarone.
Abstract: Class III drugs prolong the QT interval by blocking mainly the delayed rectifier rapid potassium outward current (IKr), with little effect on depolarization. This K(+) channel in encoded by the human ether-a-go-go-related gene (hERG). Inhibition of hERG potassium currents by class III antiarrhythmic drugs causes lengthening of cardiac action potential, which produces a beneficial antiarrhythmic effect. Excessive prolongation of the action potential may lead to acquired long QT syndrome, which is associated with a risk of "torsade de pointes". Class III agents can block all types of potassium channels: IKs, IKr, IKur and IK1. The main representing class III agent is amiodarone. It is the gold standard in the prevention of recurrence of atrial fibrillation. Although it is highly effective in treating many arrhythmias, large number of adverse effects limits its clinical use. Dronedarone is a synthetic amiodarone analogue, iodine-free compound, with fewer adverse effects, and shares amiodarone's multichannel blocking effects, inhibiting transmembrane Na+, IKs, IKur, IK1, and slow Ca(++)L-type calcium currents. The main new generation class III drugs are: dofetilide, dronedarone, azimilide, and ibutilide. Oral dofetilide did not increase mortality in patients with a recent myocardial infarction or congestive heart failure. It is an alternative for the pharmacological conversion of atrial fibrillation and flutter. Azimilide blocks both rapid and slow potassium channels components. Azimilide is not a methanesulfonanilide compound. Trecitilide, tedisamil, ersentilide, ambasilide, chromanol and sematilide are class III miscellaneous agents. Old mixed agents are sotalol and bretylium. The present article reviews the main trials accomplished with these drugs.
Abstract: Amiodarone is an effective treatment for atrial and ventricular arrhythmias, but its use is limited by a toxic adverse-effect profile. Although dronedarone has been touted as an antiarrhythmic agent devoid of both solid organ toxicity and proarrhythmic properties, its potential for prolonging ventricular repolarization may augment triggered ectopy. We describe a 66-year-old man who began dronedarone 400 mg twice/day for new-onset paroxysmal atrial fibrillation; he had no left ventricular dysfunction or clinical heart failure. Three months after starting the drug, he complained of malaise, fatigue, and rare palpitations. Twenty four-hour Holter monitoring revealed increased premature ventricular complexes, and the rate-corrected QT (QTc) interval was prolonged (range 525-760 msec). Dronedarone was discontinued and the patient's symptoms gradually resolved over the next 3 weeks. Holter monitoring revealed a marked reduction in ventricular ectopy burden, and the QTc interval decreased to his baseline values. Even in the absence of documented symptomatic torsade de pointes, this case suggests that caution should be exercised when prescribing dronedarone and that serial QTc interval monitoring may be appropriate. In addition, clinicians should have a low threshold to perform Holter monitoring if symptoms develop during dronedarone therapy.