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Drug Interactions between Prezista and st. john's wort

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

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Interactions between your drugs

Major

St. John's wort darunavir

Applies to: st. john's wort and Prezista (darunavir)

CONTRAINDICATED: Coadministration with St. John's wort may significantly reduce the plasma concentrations of HIV protease inhibitors and result in a potential loss of virologic response. The mechanism is induction of CYP450 3A4 metabolism by constituents of St. John's wort. In 8 healthy volunteers, St. John's wort (300 mg, standardized to 0.3% hypericin, 3 times a day for 14 days) decreased the 8-hour area under the plasma concentration-time curve (AUC) and extrapolated 8-hour trough of indinavir (800 mg every 8 hours for 4 doses) by a mean of 57% and 81%, respectively, compared to administration of indinavir alone. All participants showed a reduction in the indinavir 8-hour postdose concentration ranging from 49% to 99%.

MANAGEMENT: Given the risk of reduced viral susceptibility and resistance development associated with subtherapeutic antiretroviral drug levels, concomitant use of HIV protease inhibitors with St. John's wort is considered contraindicated. The enzyme induction may last for up to 2 weeks after the last dose of St. John's wort. Patients should be advised to consult with their caregivers before using any herbal or alternative medicines.

References

  1. (2001) "Product Information. Norvir (ritonavir)." Abbott Pharmaceutical
  2. Cerner Multum, Inc. "UK Summary of Product Characteristics."
  3. Cerner Multum, Inc. "Australian Product Information."
  4. Cerner Multum, Inc. (2015) "Canadian Product Information."
View all 4 references

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Drug and food interactions

Moderate

St. John's wort food

Applies to: st. john's wort

GENERALLY AVOID: An isolated case report suggests that foods containing large amounts of tyramine may precipitate a hypertensive crisis in patients treated with St. John's wort. The mechanism of interaction is unknown, as St. John's wort is not thought to possess monoamine oxidase (MAO) inhibiting activity at concentrations achieved in vivo. The case patient was a 41-year-old man who had been taking St. John's wort for seven days prior to presentation at the emergency room with confusion and disorientation. The patient recalled last eating aged cheese and having a glass of red wine approximately 10 hours prior to admission. No other cause of delirium or hypertension could be identified. In addition, alcohol may potentiate some of the pharmacologic effects of St. John's wort. Use in combination may result in additive central nervous system depression and/or impairment of judgment, thinking, and psychomotor skills.

MANAGEMENT: Until further information is available, patients treated with St. John's wort should consider avoiding consumption of protein foods in which aging or breakdown of protein is used to increase flavor. These foods include cheese (particularly strong, aged or processed cheeses), sour cream, wine (particularly red wine), champagne, beer, pickled herring, anchovies, caviar, shrimp paste, liver (particularly chicken liver), dry sausage, figs, raisins, bananas, avocados, chocolate, soy sauce, bean curd, yogurt, papaya products, meat tenderizers, fava beans, protein extracts, and dietary supplements. Caffeine may also precipitate hypertensive crisis so its intake should be minimized as well. Patients should also be advised to avoid or limit consumption of alcohol.

References

  1. Patel S, Robinson R, Burk M (2002) "Hypertensive crisis associated with St. John's Wort." Am J Med, 112, p. 507-8

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Moderate

darunavir food

Applies to: Prezista (darunavir)

ADJUST DOSING INTERVAL: Food enhances the absorption and oral bioavailability of darunavir administered in combination with low-dose ritonavir. The mechanism is unknown. When administered with food, the peak plasma concentration (Cmax) and area under the plasma concentration-time curve (AUC) of darunavir were approximately 30% higher than when administered in the fasting state. Darunavir exposure was similar for the range of meals studied. The total caloric content of the various meals evaluated ranged from 240 Kcal (12 grams fat) to 928 Kcal (56 grams fat).

MANAGEMENT: To ensure maximal oral absorption, darunavir coadministered with ritonavir should be taken with food. The type of food is not important.

References

  1. (2006) "Product Information. Prezista (darunavir)." Ortho Biotech Inc

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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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