lower and caution is advised. Venlafaxine administration is associated with a possible risk of QT prolongation; torsades de pointes (TdP) has reported with post-marketing use.
Verapamil: Dolasetron has been associated with a dose-dependant prolongation in the QT, PR, and QRS intervals on an electrocardiogram. Therefore, drugs known to prolong the PR interval should be avoided in patients taking dolasetron. Drugs that have been specifically established to have a causal association with PR prolongation include certain calcium channel blockers such as verapamil.
Vilazodone: Because of the potential risk and severity of serotonin syndrome, use caution when administering dolasetron with other drugs that have serotonergic properties such as vilazodone. If serotonin syndrome is suspected, discontinue dolasetron and concurrent serotonergic agents and initiate appropriate medical treatment. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death.
Voriconazole: Voriconazole has been associated with QT prolongation and rare cases of torsades de pointes and also is an inhibitor of CYP3A4 isoenzyme. Drugs that are substrates for CYP3A4, when combined with voriconazole, may theoretically have reduced metabolism, and therefore higher serum concentrations resulting in toxicity. The manufacturer of posaconazole, another systemic azole with potent inhibitory activity against CYP3A4, contraindicates the use of posaconazole with drugs that prolong the QT interval and are metabolized by CYP3A4. Because voriconazole also is a potent inhibitor of CYP3A4, it would be prudent to follow the same recommendations. Drugs that prolong QT and are substrates for CYP3A4 include dolasetron.
Vorinostat: Due to a possible risk for QT prolongation and torsade de pointes (TdP), dolasetron and vorinostat 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. Vorinostat therapy is associated with a risk of QT prolongation.
Ziprasidone: According to the manufacturer, ziprasidone is contraindicated with any drugs that list QT prolongation as a pharmacodynamic effect when this effect has been described within the contraindications or bolded or boxed warnings of the official labeling for such drugs. Ziprasidone has been associated with a possible risk for QT prolongation and/or torsades de pointes (TdP). Clinical trial data indicate that ziprasidone causes QT prolongation. In one study, ziprasidone increased the QT interval 10 msec more than placebo at the maximum recommended dosage. Comparative data with other antipsychotics have shown that the mean QTc interval prolongation occurring with ziprasidone exceeds that of haloperidol, quetiapine, olanzapine, and risperidone, but is less than that which occurs with thioridazine. Given the potential for QT prolongation, ziprasidone is contraindicated for use with drugs that are |
