Effect of St John's wort on the pharmacokinetics of fexofenadine

Abstract

A single dose of St John's wort resulted in a significant inhibition of intestinal P-glycoprotein. Long-term treatment with St John's wort reversed the changes in fexofenadine disposition observed with single-dose administration.

Pharmacokinetic Herb-Drug Interactions: Insight into Mechanisms and Consequences

“…A clinical study in healthy volunteers indicated a significant increase in the maximum plasma concentration of fexofenadine and a significant decrease in its oral clearance following the administration of a single dose of St John's wort. In this study, no change in the half-life or renal clearance was observed [98]. This observation was also confirmed by another clinical study in healthy volunteers which demonstrated that pretreatment with St John's wort significantly enhanced the oral clearance of fexofenadine by 1.6-fold.…”

Concurrent herb-prescription medication use and health care provider disclosure among university students

“…The first two have been shown to interact adversely with SJW. 9,13 What is most alarming is the fact that herb users who did intermix with prescriptions reported higher depression and anxiety scores. It is not known whether those higher scores might be the result of herb-prescription intermixing or whether intermixing is the result of higher scores.…”

“…5 Medications that SJW is known to adversely affect in this way include oral contraceptives, 9 antiretroviral medications used in the treatment of AIDS such as Nevirapine and Indinivar, 10,11 Digoxin, used to treat congestive heart failure, 12 and fexofenidine or Allegra, used to treat allergies. 13 Likewise, other herbal remedies used to treat mood disorders are thought to change the effects of prescription medications or exacerbate symptoms in dangerous ways. For example, valerian root and lemon balm may enhance the effects of other central nervous system depressants.…”

Complementary and Alternative Medicine During Cancer Treatment: Beyond Innocence

“…For instance, in the case of St. John's wort, ingredients with inhibitory and inducing capacities are known, and depending on the amount of the individual components, the interactive effect may totally differ. Apart from this, the duration of intake of this herbal product is also thought to influence the type of effect (first inhibition, later on induction) on drug-metabolizing and transporting proteins [76], further decreasing the possibility of predicting the occurrence of undesired clinical effects.…”