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 abarelix and paliperidone. Please also consult the relevant specialist information.
The reported changes in exposure correspond to the changes in the plasma concentration-time curve [ AUC ]. We do not expect any change in exposure for abarelix, when combined with paliperidone (100%). We do not expect any change in exposure for paliperidone, when combined with abarelix (100%).
The pharmacokinetic parameters of the average population are used as the starting point for calculating the individual changes in exposure due to the interactions.
The bioavailability of abarelix is unknown. The terminal half-life [ t12 ] is rather long at 316.8 hours and constant plasma levels [ Css ] are only reached after more than 1267.2 hours. The protein binding [ Pb ] is 97.5% strong. The metabolism via cytochromes is currently still being worked on.
Paliperidone has a low oral bioavailability [ F ] of 28%, which is why the maximum plasma level [Cmax] tends to change strongly with an interaction. The terminal half-life [ t12 ] is 23 hours and constant plasma levels [ Css ] are reached after approximately 92 hours. Protein binding [ Pb ] is not known. The metabolism via cytochromes is currently still being worked on and the active transport takes place in particular via PGP.
|Serotonergic Effects a||0||Ø||Ø|
Rating: According to our knowledge, neither abarelix nor paliperidone increase serotonergic activity.
|Kiesel & Durán b||1||Ø||+|
Recommendation: As a precaution, attention should be paid to anticholinergic symptoms, especially after increasing the dose and at doses in the upper therapeutic range.
Rating: Paliperidone only has a mild effect on the anticholinergic system. The risk of anticholinergic syndrome with this medication is rather low if the dosage is in the usual range. According to our knowledge, abarelix does not increase anticholinergic activity.
QT time prolongation
Rating: In combination, abarelix and paliperidone can potentially trigger ventricular arrhythmias of the torsades de pointes type.
General adverse effects
|Side effects||∑ frequency||aba||pal|
|Weight gain||10.5 %||n.a.||10.5|
Nasopharyngitis (5%): paliperidone
Constipation (4.5%): paliperidone
Tardive dyskinesia: paliperidone
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: The role of certain drug metabolizing enzymes in cardiotoxicity, such as CYP2D6 for thioridazine, has been suggested. Risperidone has been shown to inhibit the delayed rectifier leading to lengthening of cardiac repolarization. The heart-rate corrected QT (QTc) interval lengthening has been reported in psychiatric patients receiving risperidone under steady-state conditions. CYP2D6 is involved in the metabolism of risperidone to 9-hydroxy (OH)-risperidone. CYP2C9 enzyme is also involved in the metabolism of several psychotropic drugs, although there are no data about its implication in risperidone metabolism. The present study aimed to evaluate the influence of CYP2D6 and CYP2C9 genotypes, and plasma concentrations of risperidone and 9-OH-risperidone on the QTc interval in patients under steady-state conditions. The relevance of CYP2D6 and CYP2C9 genotypes on risperidone metabolism was also analysed. Thirty-five White European psychiatric patients receiving risperidone monotherapy were studied. QTc interval was longer (p < 0.05) in subjects with one active CYP2D6 gene compared to those with two. The number of CYP2D6 active genes was related to the dose-corrected plasma concentration of risperidone (p < 0.05), the active moiety (risperidone plus 9-OH-risperidone) (p < 0.05) and the risperidone/9-OH-risperidone ratio (p < 0.05). CYP2C9 genotypes were not related to plasma concentrations of risperidone or 9-OH-risperidone, nor QTc interval. The results suggest that CYP2D6, but not CYP2C9, may be related to QTc lengthening during treatment with risperidone. The effect of the CYP2D6 genotype in risperidone metabolism is also shown.
Abstract: BACKGROUND: Several new atypical antipsychotics have become available for use, but knowledge about their pharmacology may not be widespread. OBJECTIVE: This review aims to increase awareness and knowledge about risperidone (R) and paliperidone (9-hydroxyrisperidone [9-OHR]), their pharmacokinetics, and pharmacodynamics. METHOD: The authors present a review of the literature on R and 9-OHR. RESULTS: Oral R may be approximately twice as potent as oral 9-OHR. Levels of R and 9-OHR in R-treated patients may help clinicians prescribe 9-OHR. In R-treated patients, the R/9-OHR concentration ratio is an index of CYP2D6 activity; an inverted ratio (>1) indicates a CYP2D6 poor metabolizer (PM) or the presence of a powerful CYP2D6 inhibitor. The concentration-to-dose (C/D) ratio, where C includes R+9-OHR, is an index of total clearance from the body. A C/D ratio decreased by half is associated with CYP3A inducers or a lack of compliance, whereas an increased C/D ratio may indicate CYP2D6 PM phenotype, use of CYP2D6 and/or CYP3A4 inhibitors, or, possibly, renal insufficiency. In in-vitro studies, R and 9-OHR have similar receptor binding (except for blocking alpha(1)). 9-OHR may have less ability to enter the brain because of greater affinity for the transporter P-glycoprotein. The limited available paliperidone pharmacokinetic information suggests that there are four minor metabolic pathways. In contrast to R treatment, being a CYP2D6 PM may not be clinically relevant for paliperidone treatment. Information on paliperidone drug-drug interactions is limited. Renal excretion may be the major route of paliperidone elimination. CONCLUSION: Clinicians can use R/9-OHR and the C/D ratios to interpret plasma R levels and guide treatment.
Abstract: OBJECTIVE: A dose-dependent increase in risk of sudden cardiac death for the antipsychotic drug risperidone was reported. However, few reports have so far addressed QT prolongation associated with the use of risperidone or its major active metabolite, which is also used as a separate antipsychotic drug, paliperidone. METHODS: The present study evaluated associations between risperidone metabolism and QT interval in 61 psychiatric patients who had been receiving risperidone for ≥4 weeks at an average dosage of 4.7 mg/day. Plasma risperidone and paliperidone levels were measured and electrocardiographic measurements were also obtained. RESULTS: There was no correlation between risperidone dosage and QTc or plasma risperidone levels and QTc. However, there was a significant positive correlation between plasma paliperidone levels and QTc (r = 0.361; p = 0.004). There was no correlation between age and dose-corrected plasma risperidone levels or between age and QTc. There was a significant positive correlation between age and dose-corrected plasma paliperidone levels (r = 0.290; p = 0.023). CONCLUSION: Clinically, paliperidone is considered to play a more important role in QT prolongation than risperidone.
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: Anticholinergic drugs put elderly patients at a higher risk for falls, cognitive decline, and delirium as well as peripheral adverse reactions like dry mouth or constipation. Prescribers are often unaware of the drug-based anticholinergic burden (ACB) of their patients. This study aimed to develop an anticholinergic burden score for drugs licensed in Germany to be used by clinicians at prescribing level. METHODS: A systematic literature search in pubmed assessed previously published ACB tools. Quantitative grading scores were extracted, reduced to drugs available in Germany, and reevaluated by expert discussion. Drugs were scored as having no, weak, moderate, or strong anticholinergic effects. Further drugs were identified in clinical routine and included as well. RESULTS: The literature search identified 692 different drugs, with 548 drugs available in Germany. After exclusion of drugs due to no systemic effect or scoring of drug combinations (n = 67) and evaluation of 26 additional identified drugs in clinical routine, 504 drugs were scored. Of those, 356 drugs were categorised as having no, 104 drugs were scored as weak, 18 as moderate and 29 as having strong anticholinergic effects. CONCLUSIONS: The newly created ACB score for drugs authorized in Germany can be used in daily clinical practice to reduce potentially inappropriate medications for elderly patients. Further clinical studies investigating its effect on reducing anticholinergic side effects are necessary for validation.