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Drug Interactions between tazemetostat and Valcyte

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

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Interactions between your drugs

Moderate

valGANciclovir tazemetostat

Applies to: Valcyte (valganciclovir) and tazemetostat

GENERALLY AVOID: The use of ganciclovir or its prodrug, valganciclovir, with other drugs associated with myelosuppression and/or nephrotoxicity may increase the risk and severity of these adverse reactions due to additive effects on the kidney and bone marrow. Valganciclovir is rapidly and extensively converted to ganciclovir, which has had the following adverse reactions observed with its treatment when used alone: severe leucopenia, neutropenia, anemia, thrombocytopenia, pancytopenia, bone marrow depression, aplastic anemia, increased serum creatinine levels, and acute renal failure. Additionally, ganciclovir is primarily renally excreted; therefore, patients with impaired renal function will have increased concentrations of ganciclovir and may be at an even greater risk of experiencing adverse reactions from treatment. Theoretically when two or more medications with similar side effect profiles are given concurrently, the likelihood of experiencing these adverse reactions may be increased.

MANAGEMENT: Ganciclovir or its prodrug, valganciclovir, should generally not be combined with other drugs associated with myelosuppression and/or nephrotoxicity unless the benefits are anticipated to outweigh the potential risks. Extreme caution is advised if they are used in patients who have recently received or are receiving treatment with myelotoxic and/or nephrotoxic drugs, and vice versa. If coadministration is required, reduced dosages of one or more of the drugs may be required, and the patient should be monitored for the development of hematologic and/or renal adverse effects both during and after discontinuation of therapy.

References

  1. (2002) "Product Information. Cytovene (ganciclovir)." Genentech
  2. (2001) "Product Information. Valcyte (valganciclovir)." Roche Laboratories
  3. Cerner Multum, Inc. "UK Summary of Product Characteristics."
  4. Cerner Multum, Inc. "Australian Product Information."
View all 4 references

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Drug and food interactions

Major

tazemetostat food

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

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Moderate

valGANciclovir food

Applies to: Valcyte (valganciclovir)

ADJUST DOSING INTERVAL: Food increases the bioavailability of ganciclovir from the prodrug, valganciclovir. In 16 HIV-positive subjects, the administration of valganciclovir 875 mg once daily with a high-fat meal containing approximately 600 calories resulted in a 30% increase in the steady-state area under the plasma concentration-time curve (AUC) and a 14% increase in the peak plasma concentration (Cmax) of ganciclovir, with no delay in the time to reach peak plasma concentration (Tmax). The mechanism is unknown.

MANAGEMENT: The manufacturer recommends that valganciclovir be taken with meals.

References

  1. (2001) "Product Information. Valcyte (valganciclovir)." Roche Laboratories
  2. Brown F, Banken L, Saywell K, Arum I (1999) "Pharmacokinetics of valganciclovir and ganciclovir following multiple oral dosages of valganciclovir in HIV- and CMV-seropositiv volunteers." Clin Pharmacokinet, 37, p. 167-76

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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.

See also

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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.

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