The UK's Medicines Control Agency has issued guidance for doctors and people with HIV following the publication of a report showing that the popular herbal anti-depressant St John's Wort can cause major reductions in blood levels of indinavir.
The MCA warns that St John's Wort may theoretically affect blood levels of all protease inhibitors and levels of the NNRTIs efavirenz and nevirapine. The agency has issued factsheets for health care professionals and for patients, and suggests that people taking anti-HIV drugs who have started taking St John's Wort since their last viral load test should contact their doctor for a viral load test to check if the herbal medicine has had any adverse effect on levels of prescribed medication.
The MCA also warns that people who stop taking St John's Wort may experience toxicities caused by a rapid rebound in blood levels of certain prescription medications, including anti-HIV drugs.
The factsheets can be downloaded from the Medicines Control Agency website in pdf form.