ion, concentrations of dolasetron may be increased with concomitant use of quinine. Dolasetron is a CYP3A4 and CYP2D6 substrate and quinine is an inhibitor of both enzymes.
Ranolazine: Due to a possible risk for QT prolongation and torsade de pointes (TdP), dolasetron and ranolazine should be used together cautiously. Dolasetron has been associated with a dose-dependant prolongation in the QT, PR, and QRS intervals on an electrocardiogram. Use of dolasetron injection for the prevention of chemotherapy-induced nausea and vomiting is contraindicated because the risk of QT prolongation is higher with the doses required for this indication; when the injection is used at lower doses (i.e., those approved for post-operative nausea and vomiting) or when the oral formulation is used, the risk of QT prolongation is lower and caution is advised. Ranolazine is associated with dose- and plasma concentration-related increases in the QTc interval. The mean increase in QTc is about 6 milliseconds, measured at the Tmax of the maximum dosage (1000 mg PO twice daily). However, in 5% of the population studied, increases in the QTc of at least 15 milliseconds have been reported. Although there are no studies examining the effects of ranolazine in patients receiving other QT prolonging drugs, coadministration of such drugs may result in additive QT prolongation. In addition, in vitro studies indicate that ranolazine and its metabolite are inhibitors of CYP3A isoenzymes. The impact of coadministering ranolazine with other CYP3A4 substrates has not been studied. Ranolazine may theoretically increase plasma concentrations of dolasetron, a CYP3A4 substrate, potentially leading to adverse reactions, such as QT prolongation.
Regadenoson: Dolasetron has been associated with a dose-dependant prolongation in the QT, PR, and QRS intervals on an electrocardiogram. Use of dolasetron injection for the prevention of chemotherapy-induced nausea and vomiting is contraindicated because the risk of QT prolongation is higher with the doses required for this indication; when the injection is used at lower doses (i.e., those approved for post-operative nausea and vomiting) or when the oral formulation is used, the risk of QT prolongation is lower and caution is advised. Drugs with a possible risk for QT prolongation and torsade de pointes (TdP) that should be used cautiously with dolasetron include regadenoson.
Rifampin: Blood concentrations of hydrodolasetron, the active metabolite of dolasetron, may be decreased when dolasetron is administered concomitantly with rifampin, a potent inducer of cytochrome P450.
Rilpivirine: Due to a possible risk for QT prolongation and torsade de pointes (TdP), dolasetron and rilpivirine should be used together cautiously. Dolasetron has been associated with a dose-dependant prolongation in the QT, PR, and QRS intervals on an electrocardiogram. Use of dolasetron injection for the prevention of chemotherapy-induced nausea and vomiting is contraindicated because the risk of QT prolongation is higher with the doses required for this indication; when the injection is used at lower doses (i.e., those approved for post-operative nausea and vomiting) or when the oral formulation is used, the risk of QT prolongation is lower and caution is advised. Supratherapeutic doses of rilpivirine (75 to 300 mg/day) have caused QT prolongation; caution is advised when administering rilpivirine with other drugs that may prolong the QT or PR interval.
Risperidone: Due to a possible |
