Verlängerung der QT-Zeit
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Eklärungen für Patienten zu den Wirkstoffen
Für die Kombination von Glasdegib und Astemizol liegen uns keine zusätzlichen Warnhinweise vor. Bitte konsultieren Sie zusätzlich die jeweiligen Fachinformationen.
Die genannten Expositionsveränderungen beziehen sich jeweils auf Veränderungen der Plasmakonzentrations-Zeit-Kurve [ AUC ]. Eine Veränderung der Exposition von Glasdegib haben wir nicht erkannt. Den Einfluss von Astemizol können wir aktuell nicht abschätzen. Für Astemizol erwarten wir keine Veränderung der Exposition, wenn eine Kombination mit Glasdegib (100%) erfolgt.
Für die Berechnung der individuellen Expositionsveränderungen durch die Wechselwirkungen werden als Ausgangsbasis die pharmakokinetischen Parameter der durchschnittlichen Population verwendet.
Glasdegib hat eine mittlere orale Bioverfügbarkeit [ F ] von 77%, weshalb die maximalen Plasmaspiegel [ Cmax ] sich bei einer Interaktion tendentiell verändern. Die terminale Halbwertszeit [ t12 ] beträgt 14 Stunden und konstante Plasmaspiegel [ Css ] werden ungefähr nach 56 Stunden erreicht. Die Proteinbindung [ Pb ] ist mit 91% mässig stark und das Verteilungsvolumen [ Vd ] ist mit 200 Liter sehr gross, da die Substanz eine tiefe hepatische Extraktionsrate von 0.07 besitzt, kann eine Verdrängung aus der Proteinbindung [Pb] im Rahmen einer Interaktion die Exposition erhöhen. Die Metabolisierung findet unter anderem über CYP2C8 und CYP3A4 statt und der aktive Transport erfolgt zum Teil über PGP und UGT1A9.
Astemizol hat eine tiefe orale Bioverfügbarkeit [ F ] von 3%, weshalb die maximalen Plasmaspiegel [ Cmax ] sich bei einer Interaktion tendentiell stark verändern. Die terminale Halbwertszeit [ t12 ] beträgt 22 Stunden und konstante Plasmaspiegel [ Css ] werden ungefähr nach 88 Stunden erreicht. Die Proteinbindung [ Pb ] ist mit 97% stark. Die Metabolisierung findet unter anderem über CYP2D6 und CYP3A4 statt. Unter anderem ist Astemizol ein Hemmer von CYP3A4 und PGP.
|Serotonerge Effekte a||0||Ø||Ø|
Bewertung: Gemäss unseren Erkenntnissen erhöhen weder Glasdegib noch Astemizol die serotonerge Aktivität.
|Kiesel & Durán b||0||Ø||Ø|
Bewertung: Gemäss unseren Erkenntnissen erhöhen weder Glasdegib noch Astemizol die anticholinerge Aktivität.
Verlängerung der QT-Zeit
Bewertung: In Kombination können Glasdegib und Astemizol potentiell ventrikuläre Arrhythmien vom Typ Torsades de pointes auslösen.
|Periphere Ödeme||30.0 %||30.0||n.a.|
|Verlust von Appetit||21.0 %||21.0||n.a.|
|Veränderter Geschmackssinn||21.0 %||21.0||n.a.|
Verstopfung (20%): Glasdegib
Lungenentzündung (19%): Glasdegib
Basierend auf Ihren
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: 1. The metabolism, excretion and pharmacokinetics of glasdegib (PF-04449913) were investigated following administration of a single oral dose of 100 mg/100 μCi [C]glasdegib to six healthy male volunteers (NCT02110342). 2. The peak concentrations of glasdegib (890.3 ng/mL) and total radioactivity (1043 ngEq/mL) occurred in plasma at 0.75 hours post-dose. The AUCwere 8469 ng.h/mL and 12,230 ngEq.h/mL respectively, for glasdegib and total radioactivity. 3. Mean recovery of [C]glasdegib-related radioactivity in excreta was 91% of the administered dose (49% in urine and 42% in feces). Glasdegib was the major circulating component accounting for 69% of the total radioactivity in plasma. An N-desmethyl metabolite and an N-glucuronide metabolite of glasdegib represented 8% and 7% of the circulating radioactivity, respectively. Glasdegib was the major excreted component in urine and feces, accounting for 17% and 20% of administered dose in the 0-120 hour pooled samples, respectively. Other metabolites with abundance <3% of the total circulating radioactivity or dose in plasma or excreta were hydroxyl metabolites, a desaturation metabolite, N-oxidation and O-glucuronide metabolites. 4. Elimination of [C]glasdegib-derived radioactivity was essentially complete, with similar contribution from urinary and fecal routes. Oxidative metabolism appears to play a significant role in the biotransformation of glasdegib.
Abstract: Glasdegib (PF-04449913) is an oral small-molecule inhibitor of the Hedgehog signaling pathway under development for treating myeloid malignancies. This was an open-label phase 1, randomized, 2-sequence, 2-treatment, 2-period, crossover study evaluating the absolute bioavailability of glasdegib in healthy volunteers under fasting condition (NCT03270878). In period 1, 12 eligible subjects received either a single oral dose of glasdegib 100 mg (tablet) or a single intravenous (IV) dose of glasdegib 50 mg. Following ≥6-day washout, subjects received the treatment that they did not receive in the first period. Blood samples were collected for up to 96 hours after dosing. Drug plasma concentrations were determined by high-performance liquid chromatography-tandem mass spectrometry. Glasdegib pharmacokinetic parameters were calculated using noncompartmental analysis. The mean terminal half-life was 14.3 hours for oral tablet treatment vs 13.8 hours for glasdegib IV treatment. The absolute oral bioavailability measured as the ratios (oral/IV) of adjusted geometric mean (90% confidence interval) of dose normalized area under the plasma concentration-time curve was 77.12% (71.83%-82.81%). Two adverse events (1 mild and 1 moderate in severity) were reported by 2 subjects following oral tablet administration; these were fully resolved by the end of the study.