cardiogram. 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. Fluphenazine, a phenothiazine, is associated with a possible risk for QT prolongation.
Fluvoxamine: Because of the potential risk and severity of serotonin syndrome, use caution when administering dolasetron with other drugs that have serotonergic properties such as fluvoxamine. 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.
Furosemide: The manufacturer warns that the coadministration of dolasetron with diuretics associated with hypokalemia could increase the risk of QT prolongation. Patients taking certain diuretics may develop an electrolyte abnormality that may lead to cardiac dysrhythmias and/or QT prolongation. Hypokalemia or hypomagnesemia may occur with administration of potassium-depleting drugs such as loop diuretics increasing the potential for cardiac arrhythmias. Potassium levels should be within the normal range prior to and during therapy with dolasetron.
Gefitinib: Monitor for an increased incidence of dolasetron-related adverse effects if gefitinib and dolasetron are used concomitantly. At high concentrations, gefitinib is an inhibitor of CYP2D6, which is the primary isoenzyme responsible for the metabolism of dolasetron. In patients with solid tumors, exposure to metoprolol, another CYP2D6 substrate, was increased by 30% when given on day 15 of gefitinib dosing (500 mg daily); however, the effect of gefitinib on CYP2D6-dependent drugs is only likely to be clinically relevant when given with CYP2D6 substrates with a narrow therapeutic index or that are individually dose titrated.
Gemifloxacin: Due to an increased risk for QT prolongation and torsade de pointes (TdP), caution is advised when administering dolasetron with gemifloxacin. 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. Gemifloxacin may also prolong the QT interval in some patients. The maximal change in the QTc interval occurs approximately 5 to 10 hours following oral administration of gemifloxacin. The likelihood of QTc prolongation may increase with increasing dose of the drug; therefore, the recommended dose should not be exceeded especially in patients with renal or hepatic impairment where the Cmax and AUC are slightly higher.
Goserelin: Androgen deprivation therapy (e.g., goserelin) prolongs the QT interval; the risk may be increased with the concurrent use of drugs that may |
