Some Drug Interactions With St. John's Wort

Some antipsychotics (for example, clozapine)

St. John's wort may reduce the effectiveness of antipsychotics.

Benzodiazepines

St. John’s wort may reduce the effectiveness of these medications in reducing anxiety and may increase the risk of side effects such as drowsiness.

Cyclosporine

St. John’s wort may reduce blood levels of cyclosporine, making it less effective, with potentially dangerous results (such as rejection of an organ transplant).

Digoxin

St. John’s wort may reduce blood levels of digoxin, making it less effective, with potentially dangerous results.

Factor Xa inhibitors (for example, rivaroxaban) used as blood thinners

St. John’s wort may reduce blood levels of factor Xa inhibitors.

Imatinib (a cancer chemotherapy drug)

St. John's wort may reduce the effectiveness of imatinib.

Iron

St. John’s wort may reduce iron absorption.

Monoamine oxidase inhibitors (MAOIs)

St. John’s wort may intensify the effects of MAOIs, possibly causing very high blood pressure that requires emergency treatment.

Nonnucleoside reverse transcriptase inhibitors

St. John’s wort increases the metabolism of these medications, reducing their effectiveness.

Oral contraceptives

St. John’s wort increases the metabolism of oral contraceptives, reducing their effectiveness.

Omeprazole

St. John’s wort decreases blood levels of omeprazole, reducing its effectiveness.

Oxycodone

St. John's wort may reduce the effectiveness of oxycodone.

Medications metabolized by a certain enzyme (such as clopidogrel)

St. John's wort may reduce the effectiveness of these medications.

Phenytoin

St. John's wort may reduce the effectiveness of phenytoin.

Photosensitizing medications (such as  amiodarone, naproxen, sulfonylureas [such as glipizide], and sulfonamide antibiotics)

When taken with these medications, St. John’s wort may increase the risk of sun sensitivity.

Protease inhibitors (such as indinavir or saquinavir), which are used to treat human immunodeficiency virus (HIV) infection

St. John’s wort may reduce blood levels of protease inhibitors, making them less effective.

Selective serotonin reuptake inhibitors (SSRIs, such as fluoxetine, paroxetine, and sertraline)

St. John’s wort may intensify the effects of these medications.

Tricyclic antidepressants

St. John’s wort may decrease the effects of these medications.

Warfarin

St. John’s wort may reduce blood levels of warfarin, making it less effective and clot formation more likely.