Allongement du temps QT
Événements indésirables médicamenteux
Variantes ✨Pour une évaluation intensive des variantes par ordinateur, veuillez choisir l'abonnement standard payant.
Explications concernant les substances pour les patients
Nous n'avons pas de mise en garde supplémentaire concernant l'association de éfavirenz, clarithromycine et de cobicistat. Veuillez également consulter les informations pertinentes des spécialistes.
|Éfavirenz||1.01 [1.01,1.77] 1||1.01||1|
Les changements d'exposition rapportés correspondent aux changements de la courbe concentration-temps plasmatique [ AUC ]. L'exposition à la éfavirenz augmente à 101%, lorsqu'il est associé à la clarithromycine (101%) et à la cobicistat (100%). L'AUC est comprise entre 101% et 177% selon le
Les paramètres pharmacocinétiques de la population moyenne sont utilisés comme point de départ pour calculer les changements individuels d'exposition dus aux interactions.
La éfavirenz a une biodisponibilité orale moyenne [ F ] de 73%, c'est pourquoi les concentrations plasmatiques maximales [Cmax] ont tendance à changer avec une interaction. La demi-vie terminale [ t12 ] est assez longue (jusqu'à 47.5 heures) et des taux plasmatiques constants [ Css ] ne sont atteints qu'après plus de 190 heures. La liaison aux protéines [ Pb ] est très forte à 99.6% et le volume de distribution [ Vd ] est très grand à 184 litres, Le métabolisme a lieu via CYP1A2, CYP2B6 et CYP3A4, entre autres et le transport actif s'effectue en partie via BCRP et UGT2B7.
La clarithromycine a une biodisponibilité orale moyenne [ F ] de 53%, c'est pourquoi les concentrations plasmatiques maximales [Cmax] ont tendance à changer avec une interaction. La demi-vie terminale [ t12 ] est assez courte (4.6 heures) et des taux plasmatiques constants [ Css ] sont rapidement atteints. La liaison aux protéines [ Pb ] est plutôt faible à 70% et le volume de distribution [ Vd ] est très grand à 176 litres. Étant donné que la substance a un faible taux d'extraction hépatique de 0.13, le déplacement de la liaison aux protéines [Pb] dans le contexte d'une interaction peut entraîner une augmentation de l'exposition. Environ 27.5% d'une dose administrée sont excrétés sous forme inchangée par les reins et cette proportion est rarement modifiée par les interactions. Le métabolisme se fait principalement via CYP3A4 et le transport actif s'effectue notamment via PGP.
La biodisponibilité de la cobicistat est inconnue. La demi-vie terminale [ t12 ] est assez courte (3.5 heures) et des taux plasmatiques constants [ Css ] sont rapidement atteints. La liaison aux protéines [ Pb ] est 97.5% forte. Le métabolisme a lieu via CYP2D6 et CYP3A4, entre autres.
|Effets sérotoninergiques a||0||Ø||Ø||Ø|
Note: À notre connaissance, ni la éfavirenz, clarithromycine ni la cobicistat n'augmentent l'activité sérotoninergique.
|Kiesel & Durán b||0||Ø||Ø||Ø|
Notation: À notre connaissance, ni la éfavirenz, clarithromycine ni la cobicistat n'augmentent l'activité anticholinergique.
Allongement du temps QT
Note: En association, la éfavirenz et la clarithromycine peuvent potentiellement déclencher des arythmies ventriculaires de type torsades de pointes. Nous ne connaissons aucun potentiel d'allongement de l'intervalle QT pour la cobicistat.
Effets indésirables généraux
|Effets secondaires||∑ fréquence||éfa||cla||cob|
|La nausée||30.5 %||6.0||15.5↓||12.5|
|Démangeaison de la peau||20.4 %||11.6||n.a.||10.0|
|Mal de crâne||14.2 %||5.7||9.0↓||n.a.|
|La diarrhée||13.5 %||8.5||5.5↓||n.a.|
|Trouble du goût||13.5 %||n.a.||13.5↓||n.a.|
|Transaminases élevées||12.5 %||n.a.||n.a.||12.5|
Icterus conjonctival (10%): cobicistat
Vertiges (9.4%): cobicistat, éfavirenz
Insomnie (2%): cobicistat, clarithromycine
Trouble du rêve: éfavirenz
Prurit (9%): éfavirenz
Érythème polymorphe: éfavirenz
Syndrome de Stevens-Johnson: éfavirenz, clarithromycine
Nécrolyse épidermique toxique: clarithromycine
Créatine kinase élevée (8%): cobicistat
Rhabdomyolyse (1.9%): cobicistat, clarithromycine
Mal au dos: cobicistat
Fatigue (7.5%): éfavirenz
Douleur abdominale (4.5%): clarithromycine
Dyspepsie (4%): clarithromycine
Diarrhée à Clostridium difficile: clarithromycine
La dépression (1.6%): éfavirenz
ALT élevé: éfavirenz
AST élevé: éfavirenz
GGT élevé: éfavirenz
Insuffisance hépatique: éfavirenz
Hépatite cholestatique: clarithromycine
Réaction anaphylactique: clarithromycine
Sur la base de vos réponses et des informations scientifiques, nous évaluons le risque individuel d'effets secondaires indésirables. Ces recommandations sont destinées à conseiller les professionnels et ne se substituent pas à la consultation d'un médecin. Dans la version d'essai (alpha), le risque de toutes les substances n'a pas encore été évalué de manière concluante.
Abstract: Erythromycin, clarithromycin, and azithromycin are clinically effective for the treatment of common respiratory and skin/skin-structure infections. Erythromycin and azithromycin are also effective for treatment of nongonococcal urethritis and cervicitis due to Chlamydia trachomatis. Compared with erythromycin, clarithromycin and azithromycin offer improved tolerability. Clarithromycin, however, is more similar to erythromycin in pharmacokinetic measures such as half-life, tissue distribution, and drug interactions. Misunderstandings about differences among the macrolides (erythromycin and clarithromycin) and the azalide (azithromycin) in terms of pharmacokinetics and pharmacodynamics, spectrum of activity, safety, and cost are common. The uptake and release of these compounds by white blood cells and fibroblasts account for differences in tissue half-life, volume of distribution, intracellular:extracellular ratio, and in vivo potency. Although microbiologic studies reveal that gram-positive pathogens are equally susceptible to these agents, significantly more isolates of Haemophilus influenzae are susceptible to azithromycin than to erythromycin or clarithromycin. Concentrations achieved at the infection site and duration above the minimum inhibitory concentration are as important as in vitro activity in determining in vivo activity against bacterial pathogens. Analysis of safety data indicates differences among these agents in drug interactions and use in pregnancy. Analysis of safety data reveals pharmacokinetic drug interactions for erythromycin and clarithromycin with theophylline, terfenadine, and carbamazepine that are not found with azithromycin. Both erythromycin and azithromycin are pregnancy category B drugs; clarithromycin is a category C drug. The numerous differences in pharmacokinetics, microbiology, safety, and costs among erythromycin, clarithromycin, and azithromycin can be used in the judicious selection of treatment for indicated infections.
Abstract: To investigate whether grapefruit juice inhibits the metabolism of clarithromycin, 12 healthy subjects were given water or grapefruit juice before and after a clarithromycin dose of 500 mg in a randomized crossover study. Administration of grapefruit juice increased the time to peak concentration of both clarithromycin (82 +/- 35 versus 148 +/- 83 min; P = 0.02) and 14-hydroxyclarithromycin (84 +/- 38 min versus 173 +/- 85; P = 0.01) but did not affect other pharmacokinetic parameters.
Abstract: No Abstract available
Abstract: Efavirenz is a non-nucleoside reverse transcriptase inhibitor (NNRTI) which shows good inhibitory activity against HIV-1. Reduced susceptibility to efavirenz has been reported with HIV-1 variants containing single and multiple mutations to the reverse transcriptase enzyme. In vitro and in vivo data suggest that the resistance profile of efavirenz overlaps with that of the NNRTIs nevirapine and delavirdine. Clinically significant drug interactions have been reported with efavirenz and indinavir and saquinavir. An increase in dosage of indinavir from 800 to 1000 mg 3 times daily is recommended during coadministration with efavirenz. Use of efavirenz in combination with saquinavir as the sole protease inhibitor is not recommended. Once-daily efavirenz in combination with zidovudine plus lamivudine or indinavir or nelfinavir increased CD4+ cell counts and reduced HIV RNA plasma levels to below quantifiable levels (< 400 copies/ml) in HIV-infected patients. A sustained reduction in viral load was maintained for at least 72 weeks in 1 study. Nervous system symptoms (including headache, dizziness, insomnia and fatigue) and dermatological effects (including maculopapular rash) appear to be the most common adverse events reported with efavirenz-containing antiretroviral regimens.
Abstract: Clarithromycin is a macrolide antibacterial that differs in chemical structure from erythromycin by the methylation of the hydroxyl group at position 6 on the lactone ring. The pharmacokinetic advantages that clarithromycin has over erythromycin include increased oral bioavailability (52 to 55%), increased plasma concentrations (mean maximum concentrations ranged from 1.01 to 1.52 mg/L and 2.41 to 2.85 mg/L after multiple 250 and 500 mg doses, respectively), and a longer elimination half-life (3.3 to 4.9 hours) to allow twice daily administration. In addition, clarithromycin has extensive diffusion into saliva, sputum, lung tissue, epithelial lining fluid, alveolar macrophages, neutrophils, tonsils, nasal mucosa and middle ear fluid. Clarithromycin is primarily metabolised by cytochrome P450 (CYP) 3A isozymes and has an active metabolite, 14-hydroxyclarithromycin. The reported mean values of total body clearance and renal clearance in adults have ranged from 29.2 to 58.1 L/h and 6.7 to 12.8 L/h, respectively. In patients with severe renal impairment, increased plasma concentrations and a prolonged elimination half-life for clarithromycin and its metabolite have been reported. A dosage adjustment for clarithromycin should be considered in patients with a creatinine clearance < 1.8 L/h. The recommended goal for dosage regimens of clarithromycin is to ensure that the time that unbound drug concentrations in the blood remains above the minimum inhibitory concentration is at least 40 to 60% of the dosage interval. However, the concentrations and in vitro activity of 14-hydroxyclarithromycin must be considered for pathogens such as Haemophilus influenzae. In addition, clarithromycin achieves significantly higher drug concentrations in the epithelial lining fluid and alveolar macrophages, the potential sites of extracellular and intracellular respiratory tract pathogens, respectively. Further studies are needed to determine the importance of these concentrations of clarithromycin at the site of infection. Clarithromycin can increase the steady-state concentrations of drugs that are primarily depend upon CYP3A metabolism (e.g., astemidole, cisapride, pimozide, midazolam and triazolam). This can be clinically important for drugs that have a narrow therapeutic index, such as carbamazepine, cyclosporin, digoxin, theophylline and warfarin. Potent inhibitors of CYP3A (e.g., omeprazole and ritonavir) may also alter the metabolism of clarithromycin and its metabolites. Rifampicin (rifampin) and rifabutin are potent enzyme inducers and several small studies have suggested that these agents may significantly decrease serum clarithromycin concentrations. Overall, the pharmacokinetic and pharmacodynamic studies suggest that fewer serious drug interactions occur with clarithromycin compared with older macrolides such as erythromycin and troleandomycin.
Abstract: Two cases of QT prolongation and torsades de pointes (TdP) are presented. The patients had been taking clarithromycin (400 mg/day) for respiratory disease. Although erythromycin is reportedly associated with TdP, this is the first report of clarithromycin associated with TdP in the absence of other drugs already known to produce QT prolongation.
Abstract: OBJECTIVE: To report a case of acquired long QT syndrome that, after exclusion of all other possible causes, was probably related to therapy with efavirenz, a novel nonnucleoside reverse transcriptase inhibitor. CASE SUMMARY: This patient presented with recurrent syncope and polymorphic ventricular tachycardia, which was treated with overdrive ventricular pacing and was eliminated by discontinuation of the offending drug. DISCUSSION: This is the first reported case of QT prolongation and severe ventricular arrhythmia associated with the use of efavirenz. The temporal relationship between the initiation of treatment and the onset of electrocardiographic abnormalities, the absence of other apparent precipitating factors, as well as the normalization of QT interval and the resolution of the arrhythmia after discontinuation of the drug, strongly suggest a causal relationship between efavirenz and this adverse clinical event. CONCLUSIONS: Our case shows that any new pharmaceutical compound introduced in clinical practice may potentially result in QT prolongation and life-threatening arrhythmia.
Abstract: OBJECTIVE: The reverse transcriptase inhibitor efavirenz is currently used at a fixed dose of 600 mg/d. However, dosage individualization based on plasma concentration monitoring might be indicated. This study aimed to assess the efavirenz pharmacokinetic profile and interpatient versus intrapatient variability in patients who are positive for human immunodeficiency virus, to explore the relationship between drug exposure, efficacy, and central nervous system toxicity and to build up a Bayesian approach for dosage adaptation. METHODS: The population pharmacokinetic analysis was performed by use of NONMEM based on plasma samples from a cohort of unselected patients receiving efavirenz. With the use of a 1-compartment model with first-order absorption, the influence of demographic and clinical characteristics on oral clearance and oral volume of distribution was examined. The average drug exposure during 1 dosing interval was estimated for each patient and correlated with markers of efficacy and toxicity. The population kinetic parameters and the variabilities were integrated into a Bayesian equation for dosage adaptation based on a single plasma sample. RESULTS: Data from 235 patients with a total of 719 efavirenz concentrations were collected. Oral clearance was 9.4 L/h, oral volume of distribution was 252 L, and the absorption rate constant was 0.3 h(-1). Neither the demographic covariates evaluated nor the comedications showed a clinically significant influence on efavirenz pharmacokinetics. A large interpatient variability was found to affect efavirenz relative bioavailability (coefficient of variation, 54.6%), whereas the intrapatient variability was small (coefficient of variation, 26%). An inverse correlation between average drug exposure and viral load and a trend with central nervous system toxicity were detected. This enabled the derivation of a dosing adaptation strategy suitable to bring the average concentration into a therapeutic target from 1000 to 4000 microg/L to optimize viral load suppression and to minimize central nervous system toxicity. CONCLUSIONS: The high interpatient and low intrapatient variability values, as well as the potential relationship with markers of efficacy and toxicity, support the therapeutic drug monitoring of efavirenz. However, further evaluation is needed before individualization of an efavirenz dosage regimen based on routine drug level monitoring should be recommended for optimal patient management.
Abstract: There are few data on the use of highly active antiretroviral therapy in HIV-positive patients with end-stage renal disease. We describe the tolerability, safety and efficacy of an efavirenz-containing regimen in one such patient on continuous ambulatory peritoneal dialysis.
Abstract: Drug-drug interactions involving efavirenz are of major concern in clinical practice. We evaluated the effects of multiple doses of efavirenz on omeprazole 5-hydroxylation (CYP2C19) and sulfoxidation (CYP3A). Healthy volunteers (n = 57) were administered a single 20 mg oral dose of racemic omeprazole either with a single 600 mg oral dose of efavirenz or after 17 days of administration of 600 mg/day of efavirenz. The concentrations of racemic omeprazole, 5-hydroxyomeoprazole (and their enantiomers), and omeprazole sulfone in plasma were measured using a chiral liquid chromatography-tandem mass spectrometry method. Relative to single-dose treatment, multiple doses of efavirenz significantly decreased (P < 0.0001) the area under the plasma concentration-time curve from 0 to infinity (AUC(0-∞)) of racemic-, R- and S-omeprazole (2.01- to 2.15-fold) and the corresponding AUC(0-∞) metabolic ratio (MR) for 5-hydroxyomeprazole (1.36- to 1.44-fold) as well as the MR for omeprazole sulfone (∼2.0) (P < 0.0001). The significant reduction in the AUC of 5-hydroxyomeprazole after repeated efavirenz dosing suggests induction of sequential metabolism and mixed inductive/inhibitory effects of efavirenz on CYP2C19. In conclusion, efavirenz enhances omeprazole metabolism in a nonstereoselective manner through induction of CYP3A and CYP2C19 activity.
Abstract: The experimental pharmacoenhancer cobicistat (COBI), a potent mechanism-based inhibitor of cytochrome P450 3A enzymes, was found to inhibit the intestinal efflux transporters P-glycoprotein and breast cancer resistance protein. Consistent with its transporter inhibition, COBI significantly increased the absorptive flux of potential candidates for clinical coadministration, including the HIV protease inhibitors atazanavir and darunavir and the lymphoid cell- and tissue-targeted prodrug of the nucleotide analog tenofovir, GS-7340, through monolayers of Caco-2 cells in vitro.
Abstract: The involvement of intestinal permeability in the oral absorption of clarithromycin (CAM), a macrolide antibiotic, and telithromycin (TEL), a ketolide antibiotic, in the presence of efflux transporters was examined. In order independently to examine the intestinal and hepatic availability, CAM and TEL (10 mg/kg) were administered orally, intraportally and intravenously to rats. The intestinal and hepatic availability was calculated from the area under the plasma concentration-time curve (AUC) after administration of CAM and TEL via different routes. The intestinal availabilities of CAM and TEL were lower than their hepatic availabilities. The intestinal availability after oral administration of CAM and TEL increased by 1.3- and 1.6-fold, respectively, after concomitant oral administration of verapamil as a P-glycoprotein (P-gp) inhibitor. Further, an in vitro transport experiment was performed using Caco-2 cell monolayers as a model of intestinal epithelial cells. The apical-to-basolateral transport of CAM and TEL through the Caco-2 cell monolayers was lower than their basolateral-to-apical transport. Verapamil and bromosulfophthalein as a multidrug resistance-associated proteins (MRPs) inhibitor significantly increased the apical-to-basolateral transport of CAM and TEL. Thus, the results suggest that oral absorption of CAM and TEL is dependent on intestinal permeability that may be limited by P-gp and MRPs on the intestinal epithelial cells.
Abstract: In this study, we present efavirenz physiologically based pharmacokinetic (PBPK) model development as an example of our best practice approach that uses a stepwise approach to verify the different components of the model. First, a PBPK model for efavirenz incorporating in vitro and clinical pharmacokinetic (PK) data was developed to predict exposure following multiple dosing (600 mg q.d.). Alfentanil i.v. and p.o. drug-drug interaction (DDI) studies were utilized to evaluate and refine the CYP3A4 induction component in the liver and gut. Next, independent DDI studies with substrates of CYP3A4 (maraviroc, atazanavir, and clarithromycin) and CYP2B6 (bupropion) verified the induction components of the model (area under the curve [AUC] ratios within 1.0-1.7-fold of observed). Finally, the model was refined to incorporate the fractional contribution of enzymes, including CYP2B6, propagating autoinduction into the model (Racc 1.7 vs. 1.7 observed). This validated mechanistic model can now be applied in clinical pharmacology studies to prospectively assess both the victim and perpetrator DDI potential of efavirenz.
Abstract: BACKGROUND: Antiretroviral drugs are among the therapeutic agents with the highest potential for drug-drug interactions (DDIs). In the absence of clinical data, DDIs are mainly predicted based on preclinical data and knowledge of the disposition of individual drugs. Predictions can be challenging, especially when antiretroviral drugs induce and inhibit multiple cytochrome P450 (CYP) isoenzymes simultaneously. METHODS: This study predicted the magnitude of the DDI between efavirenz, an inducer of CYP3A4 and inhibitor of CYP2C8, and dual CYP3A4/CYP2C8 substrates (repaglinide, montelukast, pioglitazone, paclitaxel) using a physiologically based pharmacokinetic (PBPK) modeling approach integrating concurrent effects on CYPs. In vitro data describing the physicochemical properties, absorption, distribution, metabolism, and elimination of efavirenz and CYP3A4/CYP2C8 substrates as well as the CYP-inducing and -inhibitory potential of efavirenz were obtained from published literature. The data were integrated in a PBPK model developed using mathematical descriptions of molecular, physiological, and anatomical processes defining pharmacokinetics. Plasma drug-concentration profiles were simulated at steady state in virtual individuals for each drug given alone or in combination with efavirenz. The simulated pharmacokinetic parameters of drugs given alone were compared against existing clinical data. The effect of efavirenz on CYP was compared with published DDI data. RESULTS: The predictions indicate that the overall effect of efavirenz on dual CYP3A4/CYP2C8 substrates is induction of metabolism. The magnitude of induction tends to be less pronounced for dual CYP3A4/CYP2C8 substrates with predominant CYP2C8 metabolism. CONCLUSION: PBPK modeling constitutes a useful mechanistic approach for the quantitative prediction of DDI involving simultaneous inducing or inhibitory effects on multiple CYPs as often encountered with antiretroviral drugs.
Abstract: Transporters in proximal renal tubules contribute to the disposition of numerous drugs. Furthermore, the molecular mechanisms of tubular secretion have been progressively elucidated during the past decades. Organic anions tend to be secreted by the transport proteins OAT1, OAT3 and OATP4C1 on the basolateral side of tubular cells, and multidrug resistance protein (MRP) 2, MRP4, OATP1A2 and breast cancer resistance protein (BCRP) on the apical side. Organic cations are secreted by organic cation transporter (OCT) 2 on the basolateral side, and multidrug and toxic compound extrusion (MATE) proteins MATE1, MATE2/2-K, P-glycoprotein, organic cation and carnitine transporter (OCTN) 1 and OCTN2 on the apical side. Significant drug-drug interactions (DDIs) may affect any of these transporters, altering the clearance and, consequently, the efficacy and/or toxicity of substrate drugs. Interactions at the level of basolateral transporters typically decrease the clearance of the victim drug, causing higher systemic exposure. Interactions at the apical level can also lower drug clearance, but may be associated with higher renal toxicity, due to intracellular accumulation. Whereas the importance of glomerular filtration in drug disposition is largely appreciated among clinicians, DDIs involving renal transporters are less well recognized. This review summarizes current knowledge on the roles, quantitative importance and clinical relevance of these transporters in drug therapy. It proposes an approach based on substrate-inhibitor associations for predicting potential tubular-based DDIs and preventing their adverse consequences. We provide a comprehensive list of known drug interactions with renally-expressed transporters. While many of these interactions have limited clinical consequences, some involving high-risk drugs (e.g. methotrexate) definitely deserve the attention of prescribers.