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Drug Interactions between st. john's wort and Tracleer

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

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Interactions between your drugs

Moderate

St. John's wort bosentan

Applies to: st. john's wort and Tracleer (bosentan)

MONITOR: Coadministration with potent CYP450 3A4 and/or 2C9 inducers may decrease the plasma concentrations and therapeutic effects of bosentan. The proposed mechanism is increased clearance of bosentan by induction of CYP450 3A4 and/or 2C9, the isoenzymes responsible for the metabolic clearance of bosentan. In healthy subjects, concomitant use of rifampin initially led to a mean 6-fold increase in bosentan trough levels; however, after 7 days of concomitant use with bosentan 125 mg twice daily, rifampin decreased the plasma concentrations of bosentan by 58%. It was suggested that this decrease could achieve nearly 90% in an individual case.

MANAGEMENT: Until more information is available, the possibility of a diminished therapeutic response to bosentan should be considered when it is coadministered with a potent CYP450 3A4 and/or 2C9 inducer. Clinical and laboratory monitoring should be considered whenever a potent CYP450 3A4 and/or 2C9 inducer is added to or withdrawn from therapy, and the bosentan dosage adjusted as necessary.

References (2)
  1. Cerner Multum, Inc. "UK Summary of Product Characteristics."
  2. Cerner Multum, Inc. "Australian Product Information."

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

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.