QT time prolongation
Adverse drug events
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Explanations of the substances for patients
We have no additional warnings for the combination of abiraterone and amiodarone. Please also consult the relevant specialist information.
The reported changes in exposure correspond to the changes in the plasma concentration-time curve [ AUC ]. We did not detect any change in exposure to abiraterone. We currently cannot estimate the influence of amiodarone. We did not detect any change in exposure to amiodarone. We currently cannot estimate the influence of abiraterone.
The pharmacokinetic parameters of the average population are used as the starting point for calculating the individual changes in exposure due to the interactions.
Abiraterone has a mean oral bioavailability [ F ] of 50%, which is why the maximum plasma levels [Cmax] tend to change with an interaction. The terminal half-life [ t12 ] is 18 hours and constant plasma levels [ Css ] are reached after approximately 72 hours. The protein binding [ Pb ] is very strong at 99.8% and the volume of distribution [ Vd ] is very large at 2815 liters, The metabolism mainly takes place via CYP3A4.
Amiodarone has a mean oral bioavailability [ F ] of 55%, which is why the maximum plasma levels [Cmax] tend to change with an interaction. The terminal half-life [ t12 ] is rather long at 1884 hours and constant plasma levels [ Css ] are only reached after more than 7536 hours. The protein binding [ Pb ] is 96% strong. The metabolism takes place via CYP2C8 and CYP3A4, among others and the active transport takes place in particular via PGP.
|Serotonergic Effects a||0||Ø||Ø|
Rating: According to our knowledge, neither abiraterone nor amiodarone increase serotonergic activity.
|Kiesel & Durán b||0||Ø||Ø|
Rating: According to our knowledge, neither abiraterone nor amiodarone increase anticholinergic activity.
QT time prolongation
Rating: In combination, abiraterone and amiodarone can potentially trigger ventricular arrhythmias of the torsades de pointes type.
General adverse effects
|Side effects||∑ frequency||abi||ami|
|Peripheral edema||20.0 %||20.0||n.a.|
|Elevated ALT||13.0 %||13.0||n.a.|
|Elevated AST||13.0 %||13.0||n.a.|
|Urinary tract infection||10.0 %||10.0||n.a.|
Constipation (6.5%): amiodarone
Loss of appetite (6.5%): amiodarone
Diarrhea (5.5%): abiraterone
Ataxia (6.5%): amiodarone
Coordination problem (6.5%): amiodarone
Dizziness (6.5%): amiodarone
Paresthesia (6.5%): amiodarone
Peripheral neuropathy: amiodarone
Pseudotumor cerebri: amiodarone
Blurred vision (6.5%): amiodarone
Optic neuritis: amiodarone
Visual loss: amiodarone
Sepsis (5.5%): abiraterone
Hypersensitivity reaction: amiodarone
Atrial fibrillation (2.6%): abiraterone
Angina pectoris (1.6%): abiraterone
Heart failure: amiodarone
Ventricular arrhythmia: amiodarone
Hyperthyroidism (2%): amiodarone
Acute respiratory distress syndrome (2%): amiodarone
Pulmonary fibrosis: amiodarone
Stevens johnson syndrome: amiodarone
Toxic epidermal necrolysis: amiodarone
Renal failure: amiodarone
Based on your answers and scientific information, we assess the individual risk of undesirable side effects. These recommendations are intended to advise professionals and are not a substitute for consultation with a doctor. In the restricted test version (alpha), the risk of all substances has not yet been conclusively assessed.
Abstract: Amiodarone is considered to be safe in patients with prior QT prolongation and torsades de pointes taking class I antiarrhythmic agents who require continued antiarrhythmic drug therapy. However, the safety of amiodarone in advanced heart failure patients with a history of drug-induced torsades de pointes, who may be more susceptible to proarrhythmia, is unknown. Therefore, the objective of this study was to assess amiodarone safety and efficacy in heart failure patients with prior antiarrhythmic drug-induced torsades de pointes. We determined the history of torsades de pointes in 205 patients with heart failure treated with amiodarone, and compared the risk of sudden death in patients with and without such a history. To evaluate the possibility that all patients with a history of torsades de pointes would be at high risk for sudden death regardless of amiodarone treatment, we compared this risk in patients with a history of torsades de pointes who were and were not subsequently treated with amiodarone. Of 205 patients with advanced heart failure, 8 (4%) treated with amiodarone had prior drug-induced torsades de pointes. Despite similar severity of heart failure, the 1-year actuarial sudden death risk was markedly increased in amiodarone patients with than without prior torsades de pointes (55% vs 15%, p = 0.0001). Similarly, the incidence of 1-year sudden death was markedly increased in patients with prior torsades de pointes taking amiodarone compared with such patients who were not subsequently treated with amiodarone (55% vs 0%, p = 0.09).(ABSTRACT TRUNCATED AT 250 WORDS)
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: 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.
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.
Abstract: BACKGROUND: The most common acquired cause of Long QT syndrome (LQTS) is drug induced QT interval prolongation. It is an electrophysiological entity, which is characterized by an extended duration of the ventricular repolarization. Reflected as a prolonged QT interval in a surface ECG, this syndrome increases the risk for polymorphic ventricular tachycardia (Torsade de Pointes) and sudden death. METHOD: Bibliographic databases as MEDLINE and EMBASE, reports and drug alerts from several regulatory agencies (FDA, EMEA, ANMAT) and drug safety guides (ICH S7B, ICH E14) were consulted to prepare this article. The keywords used were: polymorphic ventricular tachycardia, adverse drug events, prolonged QT, arrhythmias, intensive care unit and Torsade de Pointes. Such research involved materials produced up to December 2017. RESULTS: Because of their mechanism of action, antiarrhythmic drugs such as amiodarone, sotalol, quinidine, procainamide, verapamil and diltiazem are associated to the prolongation of the QTc interval. For this reason, they require constant monitoring when administered. Other noncardiovascular drugs that are widely used in the Intensive Care Unit (ICU), such as ondansetron, macrolide and fluoroquinolone antibiotics, typical and atypical antipsychotics agents such as haloperidol, thioridazine, and sertindole are also frequently associated with the prolongation of the QTc interval. As a consequence, critical patients should be closely followed and evaluated. CONCLUSION: ICU patients are particularly prone to experience a QTc interval prolongation mainly for two reasons. In the first place, they are exposed to certain drugs that can prolong the repolarization phase, either by their mechanism of action or through the interaction with other drugs. In the second place, the risk factors for TdP are prevalent clinical conditions among critically ill patients. As a consequence, the attending physician is expected to perform preventive monitoring and ECG checks to control the QTc interval.
Abstract: Amiodarone is one of the most commonly used antiarrhythmic drugs. Despite its well-known side effects, amiodarone is considered to be a relatively safe drug, especially in short-term usage to prevent life-threatening ventricular arrhythmias. Our case demonstrates an instance where short-term usage can yield drug side effect.