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Interaction Checker
Do Not Coadminister
Ritonavir (RTV)
Quetiapine
Quality of Evidence: Very Low
Summary:
Coadministration has not been studied. Quetiapine is primarily metabolised by CYP3A4 and coadministration with ketoconazole (a CYP3A4 inhibitor) increased quetiapine AUC by 5- 8 fold. The European SPCs for quetiapine and ritonavir contraindicate coadministration. However, the US Prescribing Information for quetiapine and ritonavir recommend that quetiapine should be reduced to one sixth of the original dose if coadministered. These interaction charts reflect the more cautious option.
Description:
Due to CYP3A inhibition by ritonavir, concentrations of quetiapine are expected to increase which may lead to coma. Concomitant administration of ritonavir and quetiapine is contraindicated as it may increase quetiapine-related toxicity.
Norvir Summary of Product Characteristics, AbbVie Ltd, September 2016.
Coadministration is expected to increase quetiapine concentrations. Initiation of ritoanvir in patients taking quetiapine: consider alternative antiretroviral therapy to avoid increases in quetiapine exposures. If coadministration is necessary, reduce the quetiapine dose to 1/6 of the current dose and monitor for quetiapine-associated adverse reactions. Refer to the quetiapine prescribing information for recommendations on adverse reaction monitoring. Initiation of quetiapine in patients taking ritonavir: refer to the quetiapine prescribing information for initial dosing and titration of quetiapine.
Norvir Prescribing Information, AbbVie Inc, December 2016.
View all available interactions with Ritonavir (RTV) by clicking here.
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