St. John’s wort (hypericum)
St Johns Wort is commonly used to treat depression, anxiety and/or sleep disorders. Induces CYP3A4, CYP1A2, CYP2C9 in the liver and P-glycoprotein. Indinavir (PI) and Nevirapine (NNRTI) levels significantly reduced. Co-administration is contraindicated with all PIs, NNRTIs and Maraviroc, as St. John’s wort is expected to substantially decrease drug concentrations which may result in suboptimal levels
Echinacea
Echinacea is often used to strenghthen the immune system to help fight colds, flu or other infections. Causes inhibition of CYP1A2 and intestinal CYP3A activity and induction of hepatic CYP3A activity. As both inhibition and induction take place, the magnitude and direction of the interaction cannot be predicted
Garlic (Allium sativum)
Garlic is often used to improve cardiovascular health. In vitro can induce CYP3A4, CYP2C9 and CYP 2D6. In vivo study did show reduction in unboosted Saquinavir levels. Possibly caused by induction of gut mucosal CYP4503A4. P-glycoprotein effects are also possible. Decreased unboosted Saquinavir levels. Difficult to compare with boosted PIs, but caution should be advised.
Milk thistle (Silybum marianum)
Hepato-protective effects and therefore typically used for liver diseases such as cirrhosis and hepatitis. In vitro potential inhibitor of CYP2C9 and CYP3A4 which may lead to increased levels of PIs, NNRTIs and Maraviroc but in vivo studies have shown no effects on the levels of Indinavir and other CYP3A4 substrates. In vivo did not affect Indinavir levels, so would expect it not to affect the levels of other PIs. However, as there is no available clinical data, caution is advised when using with other PIs NNRTIs and Maraviroc.
Sutherlandia (Frutescens)
Sutherlandia is often used for its antioxidant and anti-inflammatory potential. In-vitro early inhibition of CYP3A4 and P-glycoprotein expression but then followed by induction with prolonged therapy resulting in potentially decreased drug levels. Potentially decreased drug levels of PIs NNRTIs and Maraviroc.
Source: Complementary and Alternative Therapy: Charle Maritz, Sharon Byrne and Vivian Pribram (2010)