Posaconazole and Quetiapine interaction

Posaconazole and Quetiapine: both prescribing labels describe an interaction that usually calls for monitoring, a dose change, or spacing the doses.

Moderate

Usually manageable with monitoring or a dose change. Tell your pharmacist you take both.

What the FDA labels say

From the Posaconazole (NOXAFIL) label · effective 2026-02-13

Moderate

Concomitant Use with Midazolam : Noxafil can prolong hypnotic/sedative effects.

Warnings and precautionsby drug classView label on DailyMed
Moderate

Increased plasma midazolam concentrations could potentiate and prolong hypnotic and sedative effects.

Warnings and precautionsby drug classView label on DailyMed
Moderate

Benzodiazepines that are CYP3A4 Substrates Mechanism and Clinical Effect(s) Concomitant use of posaconazole with midazolam increased midazolam plasma concentrations which could potentiate and prolong hypnotic and sedative effects [see Clinical Pharmacology (12.3) ] .

Drug interactionsby drug classView label on DailyMed

From the Quetiapine (SEROQUEL XR) label · effective 2026-04-10

Moderate

…Class 1A antiarrythmics (e.g., quinidine, procainamide) or Class III antiarrythmics (e.g., amiodarone, sotalol), antipsychotic medications (e.g., ziprasidone, chlorpromazine, thioridazine), antibiotics (e.g., gatifloxacin, moxifloxacin), or any other class of medications known to prolong the QTc interval (e.g., pentamidine, levomethadyl acetate, methadone).

Warnings and precautionsby drug classView label on DailyMed
Moderate

Quetiapine should also be avoided in circumstances that may increase the risk of occurrence of torsade de pointes and/or sudden death including (1) a history of cardiac arrhythmias such as bradycardia; (2) hypokalemia or hypomagnesemia; (3) concomitant use of other drugs that prolong the QTc interval; and (4) presence of congenital prolongation of the QT interval.

Warnings and precautionsby drug classView label on DailyMed
Moderate

• Concomitant use of strong CYP3A4 inhibitors: Reduce quetiapine dose to one‑sixth when coadministered with strong CYP3A4 inhibitors (e.g., ketoconazole, ritonavir) ( 2.5 , 7.1 , 12.3 )

Drug interactionsby drug classView label on DailyMed
Moderate

Quetiapine exposure is increased by the prototype CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, indinavir, ritonavir, nefazodone, etc.) and decreased by the prototype of CYP3A4 inducers (e.g., phenytoin, carbamazepine, rifampin, avasimibe, St.

Drug interactionsby drug classView label on DailyMed
Moderate

CYP3A4 inhibitors: Coadministration of ketoconazole, a potent inhibitor of cytochrome CYP3A4, resulted in significant increase in quetiapine exposure.

Drug interactionsby drug classView label on DailyMed

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Not medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.