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Drug Interactions between st. john's wort and Vitamin D3

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

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Interactions between your drugs

Moderate

cholecalciferol St. John's wort

Applies to: Vitamin D3 (cholecalciferol) and st. john's wort

Consumer information for this interaction is not currently available.

MONITOR: Coadministration with CYP450 inducers such as rifampin, isoniazid, barbiturates, and certain anticonvulsants may decrease the pharmacologic effects of vitamin D analogs. These agents are thought to induce the hepatic conversion of vitamin D to inactive metabolites and have been shown to reduce circulating levels of active vitamin D, sometimes accompanied by reduced serum calcium and increased parathyroid hormone levels. Patients on long-term anticonvulsant therapy have occasionally developed osteomalacia, presumably due to interference with vitamin D and calcium metabolism. There have also been isolated reports of patients who responded poorly to vitamin D supplements during treatment with phenytoin and/or primidone.

MANAGEMENT: Patients receiving vitamin D analogs with CYP450 inducers should be monitored for potentially reduced vitamin D effects. Dosage adjustments may be necessary.

References

  1. (2001) "Product Information. Rocaltrol (calcitriol)." Roche Laboratories
  2. (2001) "Product Information. Zemplar (paricalcitol)." Abbott Pharmaceutical
  3. (2004) "Product Information. Hectorol (doxercalciferol)." Genzyme Corporation
  4. (2004) "Product Information. One-Alpha (alfacalcidol)." Pharmel Inc
View all 4 references

Drug and food interactions

Moderate

St. John's wort food

Applies to: st. john's wort

While you are taking St. John's wort, you must not eat or drink certain foods and beverages that are high in tyramine. Eating these foods while you are taking St. John's wort can raise your blood pressure to dangerous levels. This may cause life threatening symptoms such as sudden and severe headache, confusion, blurred vision, problems with speech or balance, nausea, vomiting, chest pain, seizure (convulsions), and sudden numbness or weakness (especially on one side of the body). Call your doctor at once if you have any of these symptoms. Foods that are high in tyramine include: air dried meats, aged or fermented meats, sausage or salami, pickled herring, and any spoiled or improperly stored beef, poultry, fish, or liver, red wine, beer from a tap, beer that has not been pasteurize, aged cheeses, including blue, brick, brie, cheddar, parmesan, romano, and swiss, sauerkraut, over the counter supplements or cough and cold medicines that contain tyramine, soy beans, soy sauce, tofu, miso soup, bean curd, fava beans, or yeast extracts (such as Marmite). Caffeine intake should be limited as well. You should avoid or limit the use of alcohol while being treated with St. John's wort. Alcohol can increase the nervous system side effects of St. John's wort such as dizziness, drowsiness, and difficulty concentrating. Some people may also experience impairment in thinking and judgment. Talk to your doctor or pharmacist if you have any questions or concerns.

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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.