Herb-Opioid Interactions

This is a series of studies in healthy volunteers to assess the potential for adverse interactions between St. John's wort (SJW) extract and two narcotic (opioid) pain medications: oxycodone and fentanyl. In the case of oxycodone, we are interested in whether SJW treatment promotes the metabolism of oxycodone, such that it lowers the effectiveness of standard doses of oxycodone in treating pain problems. For the fentanyl study, we will investigate whether SJW treatment will interfere with the delivery of fentanyl to the brain and diminish it's effectiveness to relieve pain. There is evidence to suggest that SJW treatment may increase the activity of a transporter protein, named P-glycoprotein (Pgp), in the blood-brain barrier (BBB) that protects the brain from exposure to drugs and other dietary and environmental toxins.