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Drug Interactions between phenobarbital and Zytiga

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

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Interactions between your drugs

Major

PHENobarbital abiraterone

Applies to: phenobarbital and Zytiga (abiraterone)

GENERALLY AVOID: Coadministration with potent inducers of CYP450 3A4 may significantly decrease the plasma concentrations of abiraterone, which is partially metabolized by the isoenzyme. In healthy subjects administered a single 1000 mg dose of abiraterone following pretreatment with the potent CYP450 3A4 inducer rifampin (600 mg daily for 6 days), mean abiraterone systemic exposure (AUC) decreased by 55%.

MANAGEMENT: Concomitant use of abiraterone acetate with potent CYP450 3A4 inducers should generally be avoided. Otherwise, an increase in dosing frequency for abiraterone acetate from once daily to twice daily during the coadministration period may be considered, although this dosage adjustment has not been studied clinically. The dosage should be adjusted back to the previous level when the CYP450 3A4 inducer is discontinued. If abiraterone acetate is part of a combination pill, the regimen may need to be split into its individual components to allow for changes in abiraterone acetate dosing without affecting the other component(s).

References

  1. (2011) "Product Information. Zytiga (abiraterone)." Centocor Inc
  2. (2023) "Product Information. Akeega (abiraterone-niraparib)." Janssen Biotech, Inc.
  3. (2023) "Product Information. Akeega (abiraterone-niraparib)." Janssen Inc
  4. (2021) "Product Information. Zytiga (abiraterone)." Janssen Biotech, Inc.
  5. (2022) "Product Information. Yonsa (abiraterone)." Sun Pharmaceutical Industries
  6. (2023) "Product Information. Apo-Abiraterone (abiraterone)." Apotex Inc
  7. (2021) "Product Information. Zytiga (abiraterone)." Janssen-Cilag Pty Ltd
  8. (2023) "Product Information. Abiraterone (abiraterone)." Wockhardt UK Ltd
  9. (2023) "Product Information. Yonsa Mpred (abiraterone-methylprednisolone)." Sun Pharma ANZ Pty Ltd
View all 9 references

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Drug and food interactions

Major

PHENobarbital food

Applies to: phenobarbital

GENERALLY AVOID: Concurrent acute use of barbiturates and ethanol may result in additive CNS effects, including impaired coordination, sedation, and death. Tolerance of these agents may occur with chronic use. The mechanism is related to inhibition of microsomal enzymes acutely and induction of hepatic microsomal enzymes chronically.

MANAGEMENT: The combination of ethanol and barbiturates should be avoided.

References

  1. Gupta RC, Kofoed J (1966) "Toxological statistics for barbiturates, other sedatives, and tranquilizers in Ontario: a 10-year survey." Can Med Assoc J, 94, p. 863-5
  2. Misra PS, Lefevre A, Ishii H, Rubin E, Lieber CS (1971) "Increase of ethanol, meprobamate and pentobarbital metabolism after chronic ethanol administration in man and in rats." Am J Med, 51, p. 346-51
  3. Saario I, Linnoila M (1976) "Effect of subacute treatment with hypnotics, alone or in combination with alcohol, on psychomotor skills related to driving." Acta Pharmacol Toxicol (Copenh), 38, p. 382-92
  4. Stead AH, Moffat AC (1983) "Quantification of the interaction between barbiturates and alcohol and interpretation of fatal blood concentrations." Hum Toxicol, 2, p. 5-14
  5. Seixas FA (1979) "Drug/alcohol interactions: avert potential dangers." Geriatrics, 34, p. 89-102
View all 5 references

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Moderate

abiraterone food

Applies to: Zytiga (abiraterone)

ADJUST DOSING INTERVAL: Food may significantly increase the oral bioavailability of some formulations of abiraterone acetate. Compared to administration in the fasted state, abiraterone peak plasma concentration (Cmax) and systemic exposure (AUC) were approximately 7- and 5-fold higher, respectively, when a single dose of abiraterone acetate was administered with a low-fat meal (7% fat; 300 calories) and approximately 17- and 10-fold higher, respectively, when it was administered with a high-fat meal (57% fat; 825 calories). Given the normal variation in the content and composition of meals, taking abiraterone acetate with meals has the potential to result in increased and highly variable exposures. The safety of these increased exposures during multiple dosing has not been assessed. However, the abiraterone acetate 125 mg tablet, commonly marketed as Yonsa, was found to have an approximately 6.5-fold higher Cmax and 4.4-fold higher AUC when a single dose of 500 mg (4 tablets) was administered with a high-fat meal (56% - 60% fat, 900 - 1000 calories) compared to overnight fasting in healthy volunteers. These differences were not considered clinically significant for this formulation.

MANAGEMENT: Some formulations of abiraterone acetate must be taken on an empty stomach. No food should be consumed for at least two hours before and one hour after the abiraterone acetate dose. However, the abiraterone acetate 125 mg tablet, commonly marketed as Yonsa, can be taken with or without food. The manufacturer's product labeling should be consulted for specific guidance.

References

  1. (2011) "Product Information. Zytiga (abiraterone)." Centocor Inc
  2. (2023) "Product Information. Akeega (abiraterone-niraparib)." Janssen Biotech, Inc.
  3. (2023) "Product Information. Akeega (abiraterone-niraparib)." Janssen Inc
  4. (2021) "Product Information. Zytiga (abiraterone)." Janssen Biotech, Inc.
  5. (2022) "Product Information. Yonsa (abiraterone)." Sun Pharmaceutical Industries
  6. (2023) "Product Information. Apo-Abiraterone (abiraterone)." Apotex Inc
  7. (2021) "Product Information. Zytiga (abiraterone)." Janssen-Cilag Pty Ltd
  8. (2023) "Product Information. Abiraterone (abiraterone)." Wockhardt UK Ltd
  9. (2023) "Product Information. Yonsa Mpred (abiraterone-methylprednisolone)." Sun Pharma ANZ Pty Ltd
View all 9 references

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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.

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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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