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Drug Interactions between quetiapine and tazemetostat

This report displays the potential drug interactions for the following 2 drugs:

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Interactions between your drugs

Moderate

QUEtiapine tazemetostat

Applies to: quetiapine and tazemetostat

MONITOR: Coadministration with inducers of CYP450 3A4 may decrease the plasma concentrations of quetiapine, which is primarily metabolized by the isoenzyme. In 18 psychiatric patients receiving quetiapine 300 mg twice daily, addition of the potent CYP450 3A4 inducer carbamazepine (200 mg three times daily) decreased mean quetiapine peak plasma concentration (Cmax) and systemic exposure (AUC) by 80% and 87%, respectively, and increased oral clearance (Cl/F) by 7.5-fold compared to quetiapine administered alone. The interaction has also been reported with phenytoin, another potent CYP450 3A4 inducer. In ten subjects with various affective disorders, coadministration of quetiapine (250 mg orally three times a day) with phenytoin (100 mg orally three times a day) decreased the mean steady-state Cmax, trough plasma concentration (Cmin) and AUC of quetiapine by 66%, 89% and 80%, respectively. The mean oral clearance increased by 5.5-fold. No data are available for other, less potent CYP450 3A4 inducers.

MANAGEMENT: Pharmacologic response to quetiapine should be monitored more closely whenever a CYP450 3A4 inducer is added to or withdrawn from therapy, and the quetiapine dosage adjusted as necessary. Patients should be advised to notify their physician if their symptoms worsen or their condition changes.

References (5)
  1. (2001) "Product Information. Seroquel (quetiapine)." Astra-Zeneca Pharmaceuticals
  2. (1997) "Quetiapine for schizophrenia." Med Lett Drugs Ther, 39, p. 117-8
  3. Wong YWJ, Yeh C, Thyrum PT (2001) "The effects of concomitant phenytoin administration on the steady-state pharmacokinetics of quetiapine." J Clin Psychopharmacol, 21, p. 89-93
  4. Grimm SW, Richtand NM, Winter HR, Stams KR, Reele SB (2006) "Effects of cytochrome P450 3A modulators ketoconazole and carbamazepine on quetiapine pharmacokinetics." Br J Clin Pharmacol, 61, p. 58-69
  5. Cerner Multum, Inc. "Australian Product Information."

Drug and food/lifestyle interactions

Major

tazemetostat food/lifestyle

Applies to: tazemetostat

GENERALLY AVOID: Consumption of grapefruit or grapefruit juice during tazemetostat therapy may significantly increase the plasma concentrations of tazemetostat. The proposed mechanism is inhibition of the CYP450 3A4-mediated metabolism of tazemetostat by certain compounds in grapefruit. Because grapefruit juice inhibits primarily intestinal rather than hepatic CYP450 3A4, the magnitude of interaction is greatest for those drugs that undergo significant presystemic metabolism by CYP450 3A4 (i.e., drugs with low oral bioavailability). According to the product labeling, coadministration of tazemetostat (400 mg twice daily) with the moderate CYP450 3A4 inhibitor fluconazole increased the tazemetostat steady state exposure (AUC 0 to 8 hours) by 3.1-fold and peak plasma concentration by 2.3-fold. In general, the effect of grapefruit juice is concentration-, dose- and preparation-dependent, and can vary widely among brands. Certain preparations of grapefruit juice (e.g., high dose, double strength) have sometimes demonstrated potent inhibition of CYP450 3A4, while other preparations (e.g., low dose, single strength) have typically demonstrated moderate inhibition. Pharmacokinetic interactions involving grapefruit juice are also subject to a high degree of interpatient variability, thus the extent to which a given patient may be affected is difficult to predict. Clinically, this interaction may result in an increased risk of the frequency or severity of adverse reactions due to tazemetostat such as hemorrhage, pleural effusion, skin infection, dyspnea, pain, and respiratory distress.

MANAGEMENT: The manufacturer advises that patients treated with tazemetostat should avoid consumption of grapefruit or grapefruit juice.

References (1)
  1. (2020) "Product Information. Tazverik (tazemetostat)." Epizyme, Inc
Moderate

QUEtiapine food/lifestyle

Applies to: quetiapine

GENERALLY AVOID: Grapefruit juice and/or grapefruit may increase the plasma concentrations of quetiapine. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit. Inhibition of hepatic CYP450 3A4 may also contribute. The interaction has not been studied with grapefruit juice but has been reported for other CYP450 3A4 inhibitors. For example, in 12 healthy volunteers, administration of a single 25 mg dose of quetiapine with the potent CYP450 3A4 inhibitor ketoconazole (200 mg once daily for 4 days) increased mean quetiapine peak plasma concentration (Cmax) and systemic exposure (AUC) by 3.4- and 6.2-fold, respectively, and decreased mean oral clearance by 84%. In general, the effects of grapefruit products are concentration-, dose- and preparation-dependent, and can vary widely among brands. Certain preparations of grapefruit (e.g., high dose, double strength) have sometimes demonstrated potent inhibition of CYP450 3A4, while other preparations (e.g., low dose, single strength) have typically demonstrated moderate inhibition. High plasma levels of quetiapine may increase the risk and/or severity of serious adverse effects such as extrapyramidal symptoms, tardive dyskinesia, hyperglycemia, dyslipidemia, hyperprolactinemia, orthostatic hypotension, blood pressure increases (in children and adolescents), priapism, QT prolongation, cognitive and motor impairment, dysphagia, heat-related illnesses due to disruption of body temperature regulation, and symptoms of serotonin syndrome (e.g., mental status changes such as irritability, altered consciousness, confusion, hallucination, and coma; autonomic dysfunction such as tachycardia, hyperthermia, diaphoresis, shivering, blood pressure lability, and mydriasis; neuromuscular abnormalities such as hyperreflexia, myoclonus, tremor, rigidity, and ataxia; and gastrointestinal symptoms such as abdominal cramping, nausea, vomiting, and diarrhea).

Food may have varying effects on the absorption of quetiapine from immediate-release versus prolonged-release formulations. In a study examining the effects of food on the bioavailability of quetiapine, a high-fat meal was found to produce statistically significant increases in the quetiapine prolonged release Cmax and AUC of approximately 50% and 20%, respectively. It cannot be excluded that the effect of a high fat meal on the formulation may be larger. In comparison, a light meal had no significant effect on the Cmax or AUC of quetiapine.

Quetiapine may potentiate the cognitive and motor effects of alcohol. The mechanism is likely related to the primary central nervous system effects of quetiapine.

MANAGEMENT: According to the manufacturer, consumption of grapefruit juice should be avoided during treatment with quetiapine. Quetiapine immediate-release tablets may be taken with or without food. It is recommended that quetiapine prolonged release is taken once daily without food or with a light meal. Consumption of alcohol should be limited and used with caution while taking quetiapine.

References (10)
  1. Cerner Multum, Inc. "UK Summary of Product Characteristics."
  2. Cerner Multum, Inc. "Australian Product Information."
  3. Agencia Española de Medicamentos y Productos Sanitarios Healthcare (2008) Centro de información online de medicamentos de la AEMPS - CIMA. https://cima.aemps.es/cima/publico/home.html
  4. (2023) "Product Information. Aliquen (QUETIAPine)." Pharmacor Limited
  5. (2024) "Product Information. Mintreleq XL (quetiapine)." Aristo Pharma Ltd
  6. (2025) "Product Information. QUEtiapine Fumarate (QUEtiapine)." XLCare Pharmaceuticals, Inc
  7. (2024) "Product Information. QUEtiapine Fumarate ER (QUEtiapine)." ScieGen Pharmaceuticals, Inc.
  8. (2025) "Product Information. Apo-Quetiapine (quetiapine)." Apotex Inc
  9. Miyamatsu, Y., Tanizaki, R. (2021) "Serotonin syndrome triggered by increasing the dose of quetiapine" Clinical practice and cases in emergency medicine, 5, p. 365-366
  10. Kohen, I., Gordon, M.L., Manu, P. (2007) "Serotonin syndrome in elderly patients treated for psychotic depression with atypical antipsychotics and antidepressants: two case reports" CNS Spectr, 12, p. 596-8

Therapeutic duplication warnings

No warnings were found for your selected drugs.

Therapeutic duplication warnings are only returned when drugs within the same group exceed the recommended therapeutic duplication maximum.


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Drug Interaction Classification

These classifications are only a guideline. The relevance of a particular drug interaction to a specific individual is difficult to determine. Always consult your healthcare provider before starting or stopping any medication.
Major Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit.
Moderate Moderately clinically significant. Usually avoid combinations; use it only under special circumstances.
Minor Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan.
Unknown No interaction information available.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.