Qvex Drug Interactions

The central effects of other CNS depressants, including alcohol, may be enhanced by Quetiapine. Quetiapine should be used with caution in patients also receiving antihypertensives or drugs that prolong the QT interval.
Quetiapine may antagonise the actions of dopaminergics such as levodopa. CYP3A4 is the main isoenzyme responsible for cytochrome P450-mediated metabolism of Quetiapine and caution is advised when quetiapine is used with potent inhibitors of CYP3A4 such as erythromycin, fluconazole, itraconazole and ketoconazole; lower doses of quetiapine should be used when given with such drugs.
Conversely, enzyme inducers such as carbamazepine and phenytoin may decrease the plasma concentrations of quetiapine, and higher doses of quetiapine may be necessary. Thioridazine has also been reported to increase the clearance of quetiapine.
Antibacterials: Antibacterials such as erythromycin inhibited Quetiapine's metabolism by the cytochrome P450 isoenzyme CYP3A4. Modification of dosage was recommended in this patient group taking these two drugs together.
Antipsychotics: Asymptomatic QT prolongation associated with Quetiapine in a patient receiving Risperidone.