Avvisi di avvertenza
Estensione di tempo QT
Effetti avversi del farmaco
Varianti ✨Per la valutazione computazionalmente intensiva delle varianti, scegli l'abbonamento standard a pagamento.
Aree di applicazione
Spiegazioni per i pazienti
Avvisi di avvertenza
Non abbiamo ulteriori avvertenze per la combinazione di terbinafina e abiraterone. Si prega di consultare anche le informazioni specialistiche pertinenti.
|Terbinafina||1.09 [1.09,1.09] 1||1.09|
I cambiamenti nell'esposizione menzionati si riferiscono ai cambiamenti nella curva concentrazione plasmatica-tempo [AUC]. L'esposizione alla terbinafina aumenta al 109%, se combinato con abiraterone (109%). L'AUC è compresa tra 109% e 109% a seconda del
I parametri farmacocinetici della popolazione media sono utilizzati come punto di partenza per il calcolo delle singole variazioni di esposizione dovute alle interazioni.
La terbinafina ha una bassa biodisponibilità orale [ F ] del 40%, motivo per cui il livello plasmatico massimo [Cmax] tende a cambiare fortemente con un'interazione. L'emivita terminale [ t12 ] è di 24 ore e i livelli plasmatici costanti [ Css ] vengono raggiunti dopo circa 96 ore. Il legame proteico [ Pb ] è molto forte al 99%. Poiché la sostanza ha una bassa velocità di estrazione epatica di 0,9, lo spostamento dal legame proteico [Pb] nel contesto di un'interazione può aumentare l'esposizione. Il metabolismo avviene tramite CYP1A2, CYP2C19, CYP2C8, CYP2C9 e CYP3A4, tra gli altri.
La abiraterone ha una biodisponibilità orale media [ F ] del 50%, motivo per cui i livelli plasmatici massimi [Cmax] tendono a cambiare con un'interazione. L'emivita terminale [ t12 ] è di 18 ore e i livelli plasmatici costanti [ Css ] vengono raggiunti dopo circa 72 ore. Il legame proteico [ Pb ] è molto forte al 99.8% e il volume di distribuzione [ Vd ] è molto grande a 2815 litri, Il metabolismo avviene principalmente tramite CYP3A4.
|Effetti serotoninergici a||0||Ø||Ø|
Valutazione: Secondo le nostre conoscenze, né la terbinafina né la abiraterone aumentano l'attività serotoninergica.
|Kiesel & Durán b||0||Ø||Ø|
Valutazione: Secondo i nostri risultati, né la terbinafina né la abiraterone aumentano l'attività anticolinergica.
Estensione di tempo QT
La abiraterone può potenzialmente aumentare il tempo dell'intervallo QT, ma non sappiamo delle aritmie di torsione di punta. Non conosciamo alcun potenziale di prolungamento dell'intervallo QT per la terbinafina.
Effetti collaterali generali
|Effetti collaterali||∑ frequenza||ter||abi|
|Edema periferico||20.0 %||n.a.||20.0|
|ALT aumentata||13.0 %||n.a.||13.0|
|AST aumentata||13.0 %||n.a.||13.0|
|Eruzione cutanea||10.0 %||10.0||n.a.|
|Perdita di appetito||10.0 %||10.0||n.a.|
|Mal di testa||10.0 %||10.0||n.a.|
|Infezione del tratto urinario||10.0 %||n.a.||10.0|
Sepsi (5.5%): abiraterone
Reazione anafilattica: terbinafina
Lupus eritematoso sistemico: terbinafina
Disturbo del gusto (2.8%): terbinafina
Nausea (2.3%): terbinafina
Fibrillazione atriale (2.6%): abiraterone
Angina pectoris (1.6%): abiraterone
Visione offuscata: terbinafina
Infezione delle vie respiratorie superiori: terbinafina
Perdita dell'udito: terbinafina
Lupus eritematoso cutaneo: terbinafina
Eritema multiforme: terbinafina
Pustolosi esantematica generalizzata: terbinafina
Sindrome di Stevens Johnson: terbinafina
Necrolisi epidermica tossica: terbinafina
Epatite colestatica: terbinafina
Insufficienza epatica: terbinafina
Sulla base delle vostre
Abstract: The plasma pharmacokinetics, and the urinary excretion, of terbinafine and its five main metabolites have been investigated after a single oral dose administration of 125 mg to 16 healthy subjects. In plasma, the highest concentrations are observed for the two carboxybutyl metabolites, with a predominance for the carboxybutylterbinafine. For this metabolite, as compared to terbinafine, the Cmax and AUC are 2.4 and 13 times higher respectively. The demethylterbinafine presents a plasma profile close to that of terbinafine. The two hydroxy metabolites are only found as glucuronide and are of minor importance. The apparent terminal half-lives of terbinafine, demethylterbinafine, and the two carboxy metabolites appear to be similar (approximately 25 h). As compared to the plasma concentration of total radioactivity observed after a single oral administration of the same dose of 14C-terbinafine, the parent drug and these five metabolites, account for more than 80% of the total radioactivity in plasma over the 0-48 h interval following administration. In urine, the major metabolite is demethylcarboxybutylterbinafine, which amounted to about 10% of the administered dose. Terbinafine and demethylterbinafine are only excreted as trace amounts in urine. Carboxybutylterbinafine and the two hydroxy metabolites are excreted in the range of 0.5-2% either as glucuronides or free. Urinary excretion over the 0-48 h interval of terbinafine and of the five metabolites amounted to about 14% of the administered dose. This is far below the level of total radioactivity measured in urine over the same interval (approximately 57%), after administration of 14C-terbinafine. This shows in contrast to plasma, that numerous other metabolites are present in urine.
Abstract: BACKGROUND: Two new systemic antifungal agents, terbinafine and itraconazole, have expanded the choices for treatment of onychomycosis. The pharmacokinetic and pharmacologic properties provide the basis of their activity and are related to their efficacy and safety in dermatophyte infections. OBJECTIVE: We describe the pharmacodynamics, pharmacokinetics, and pharmacology of terbinafine and itraconazole and the features that form a framework for comparing their efficacy. PHARMACODYNAMICS: Both terbinafine and itraconazole ultimately block ergosterol synthesis; terbinafine disrupts fungal cell wall synthesis earlier (squalene to squalene epoxide) than does itraconazole (lanosterol to ergosterol). In vitro, terbinafine exposure results in a toxic accumulation of squalene and decreased production of ergosterol. Minimal inhibitory concentrations (MICs) of terbinafine for dermatophytes are essentially equal to minimal fungicidal concentrations (MFCs). However, the MFCs of itraconazole are much higher than the MICs. PHARMACOLOGIC PROFILE: Both itraconazole and terbinafine penetrate keratinizing tissue; levels reached in nail plate exceed those in plasma. Therapeutic levels of the itraconazole persist in nails for up to 6 months after discontinuation of 3 months of therapy (200 mg/day) and during various pulsed cycles. After discontinuation of 1 month of therapy, terbinafine persists at therapeutic levels in the nail. Itraconazole has an affinity for mammalian cytochrome P-450 enzymes as well as for fungal P-450-dependent enzyme, and thus has the potential for clinically important interactions (e.g., astemizole, terfenadine, rifampin, oral contraceptives, H2 receptor antagonists, warfarin, cyclosporine). Terbinafine is not metabolized through this system and has little potential for drug-drug interactions. CONCLUSION: The low MFCs exhibited by terbinafine for dermatophytes may be important in its clinical efficacy and low relapse rates. The safety profile of terbinafine directly reflects its mechanism of action.
Abstract: Biotransformation pathways and the potential for drug-drug interactions of the orally active antifungal terbinafine were characterized using human liver microsomes and recombinant human cytochrome P-450s (CYPs). The terbinafine metabolites represented four major pathways: 1) N-demethylation, 2) deamination, 3) alkyl side chain oxidation, and 4) dihydrodiol formation. Michaelis-Menten kinetics for the pathways revealed mean K(m) values ranging from 4.4 to 27.8 microM, and V(max) values of 9.8 to 82 nmol/h/mg protein. At least seven CYP enzymes are involved in terbinafine metabolism. Recombinant human CYPs predict that CYP2C9, CYP1A2, and CYP3A4 are the most important for total metabolism. N-demethylation is primarily mediated by CYP2C9, CYP2C8, and CYP1A2; dihydrodiol formation by CYP2C9 and CYP1A2; deamination by CYP3A4; and side chain oxidation equally by CYP1A2, CYP2C8, CYP2C9, and CYP2C19. Additionally, characteristic CYP substrates inhibited pathways of terbinafine metabolite formation, confirming the involvement of multiple enzymes. The deamination pathway was mainly inhibited by CYP3A inhibitors, including troleandomycin and azole antifungals. Dihydrodiol formation was inhibited by the CYP1A2 inhibitor furafylline. Terbinafine had little or no effect on the metabolism of many characteristic CYP substrates. Terbinafine, however, is a competitive inhibitor of the CYP2D6 reaction, dextromethorphan O-demethylation (K(i) = 0.03 microM). In summary, terbinafine is metabolized by at least seven CYPs. The potential for terbinafine interaction with other drugs is predicted to be insignificant with the exception that it may inhibit the metabolism of CYP2D6 substrates. Clinical trials are needed to assess the relevance of these findings.
Abstract: The aim of this study was to develop a physiologically based pharmacokinetic (PB-PK) model capable of describing and predicting terbinafine concentrations in plasma and tissues in rats and humans. A PB-PK model consisting of 12 tissue and 2 blood compartments was developed using concentration-time data for tissues from rats (n = 33) after intravenous bolus administration of terbinafine (6 mg/kg of body weight). It was assumed that all tissues except skin and testis tissues were well-stirred compartments with perfusion rate limitations. The uptake of terbinafine into skin and testis tissues was described by a PB-PK model which incorporates a membrane permeability rate limitation. The concentration-time data for terbinafine in human plasma and tissues were predicted by use of a scaled-up PB-PK model, which took oral absorption into consideration. The predictions obtained from the global PB-PK model for the concentration-time profile of terbinafine in human plasma and tissues were in close agreement with the observed concentration data for rats. The scaled-up PB-PK model provided an excellent prediction of published terbinafine concentration-time data obtained after the administration of single and multiple oral doses in humans. The estimated volume of distribution at steady state (V(ss)) obtained from the PB-PK model agreed with the reported value of 11 liters/kg. The apparent volume of distribution of terbinafine in skin and adipose tissues accounted for 41 and 52%, respectively, of the V(ss) for humans, indicating that uptake into and redistribution from these tissues dominate the pharmacokinetic profile of terbinafine. The PB-PK model developed in this study was capable of accurately predicting the plasma and tissue terbinafine concentrations in both rats and humans and provides insight into the physiological factors that determine terbinafine disposition.
Abstract: Three open-label, single-dose studies investigated the impact of hepatic or renal impairment on abiraterone acetate pharmacokinetics and safety/tolerability in non-cancer patients. Patients (n = 8 each group) with mild/moderate hepatic impairment or end-stage renal disease (ESRD), and age-, BMI-matched healthy controls received a single oral 1,000 mg abiraterone acetate (tablet dose); while patients (n = 8 each) with severe hepatic impairment and matched healthy controls received 125- and 2,000-mg abiraterone acetate (suspension doses), respectively (systemic exposure of abiraterone acetate suspension is approximately half to that of tablet formulation). Blood was sampled at specified timepoints up to 72 or 96 hours postdose to measure plasma abiraterone concentrations. Abiraterone exposure was comparable between healthy controls and patients with mild hepatic impairment or ESRD, but increased by 4-fold in patients with moderate hepatic impairment. Despite a 16-fold reduction in dose, abiraterone exposure in patients with severe hepatic impairment was about 22% and 44% of the Cmax and AUC∞ of healthy controls, respectively. These results suggest that abiraterone pharmacokinetics were not changed markedly in patients with ESRD or mild hepatic impairment. However, the capacity to eliminate abiraterone was substantially compromised in patients with moderate or severe hepatic impairment. A single-dose administration of abiraterone acetate was well-tolerated.
Abstract: BACKGROUND: Tramadol is widely used for acute, chronic, and neuropathic pain. Its primary active metabolite is O-desmethyltramadol (M1), which is mainly accountable for the μ-opioid receptor-related analgesic effect. Tramadol is metabolized to M1 mainly by cytochrome P450 (CYP)2D6 enzyme and to other metabolites by CYP3A4 and CYP2B6. We investigated the possible interaction of tramadol with the antifungal agents terbinafine (CYP2D6 inhibitor) and itraconazole (CYP3A4 inhibitor). METHODS: We used a randomized placebo-controlled crossover study design with 12 healthy subjects, of which 8 were extensive and 4 were ultrarapid CYP2D6 metabolizers. On the pretreatment day 4 with terbinafine (250 mg once daily), itraconazole (200 mg once daily) or placebo, subjects were given tramadol 50 mg orally. Plasma concentrations of tramadol and M1 were determined over 48 h and some pharmacodynamic effects over 12 h. Pharmacokinetic variables were calculated using standard non-compartmental methods. RESULTS: Terbinafine increased the area under plasma concentration-time curve (AUC0-∞) of tramadol by 115 % and decreased the AUC0-∞ of M1 by 64 % (P < 0.001). Terbinafine increased the peak concentration (C max) of tramadol by 53 % (P < 0.001) and decreased the C max of M1 by 79 % (P < 0.001). After terbinafine pretreatment the elimination half-life of tramadol and M1 were increased by 48 and 50 %, respectively (P < 0.001). Terbinafine reduced subjective drug effect of tramadol (P < 0.001). Itraconazole had minor effects on tramadol pharmacokinetics. CONCLUSIONS: Terbinafine may reduce the opioid effect of tramadol and increase the risk of its monoaminergic adverse effects. Itraconazole has no meaningful interaction with tramadol in subjects who have functional CYP2D6 enzyme.
Abstract: Two novel oral drugs that target androgen signaling have recently become available for the treatment of metastatic castration-resistant prostate cancer (mCRPC). Abiraterone acetate inhibits the synthesis of the natural ligands of the androgen receptor, whereas enzalutamide directly inhibits the androgen receptor by several mechanisms. Abiraterone acetate and enzalutamide appear to be equally effective for patients with mCRPC pre- and postchemotherapy. Rational decision making for either one of these drugs is therefore potentially driven by individual patient characteristics. In this review, an overview of the pharmacokinetic characteristics is given for both drugs and potential and proven drug-drug interactions are presented. Additionally, the effect of patient-related factors on drug disposition are summarized and the limited data on the exposure-response relationships are described. The most important pharmacological feature of enzalutamide that needs to be recognized is its capacity to induce several key enzymes in drug metabolism. The potency to cause drug-drug interactions needs to be addressed in patients who are treated with multiple drugs simultaneously. Abiraterone has a much smaller drug-drug interaction potential; however, it is poorly absorbed, which is affected by food intake, and a large interpatient variability in drug exposure is observed. Dose reductions of abiraterone or, alternatively, the selection of enzalutamide, should be considered in patients with hepatic dysfunction. Understanding the pharmacological characteristics and challenges of both drugs could facilitate decision making for either one of the drugs.
Abstract: We present a case of a 77 year-old gentleman with previous coronary artery bypass grafting, admitted to hospital with recurrent torsades de pointes (TdP) due to abiraterone-induced hypokalaemia and prolonged QTc. The patient was on abiraterone and prednisone for metastatic prostate cancer. He required multiple defibrillations for recurrent TdP. Abiraterone is a relatively novel drug used in metastatic prostate cancer and we discuss this potential adverse effect and its management in this unusual presentation.