AIDS Patients Warned About St. John’s Wort

The popular herbal supplement St. John’s wort interferes with essential medications prescribed for people with the AIDS virus and for organ transplant recipients, according to two reports released Thursday.

Based on the findings, the Food and Drug Administration warned against taking the herb and the AIDS drug indinavir together. The agency also urged doctors to learn whether their patients are taking St. John’s wort, because the herb may diminish the effects of several other anti-viral drugs that fight the human immunodeficiency virus, which causes AIDS.

A co-author of the report was even more blunt. “Most people taking medications to treat HIV infection should avoid using St. John’s wort,” said Dr. Judith Falloon, an AIDS specialist at the National Institute of Allergy and Infectious Diseases.

In the study, National Institutes of Health researchers found that the herb reduced blood levels of indinavir, or Crixivan, by as much as 80%. That could hinder its ability to fight the virus and could foster the spread of virus strains that do not respond to drugs at all, the researchers said.

In the other report, physicians in Zurich, Switzerland, said two heart transplant recipients who were fine for nearly a year began rejecting donated organs just weeks after they started consuming St. John’s wort. The herb appeared to negate the benefits of the cyclosporine they were taking to prevent rejection.

Both studies also raise the possibility that St. John’s wort may negatively interact with other medications, including the tranquilizer Valium and oral contraceptives. That is because the herb appears to boost the action of one of the cytochrome P450 enzymes, which are abundant in the liver and help break down and eliminate many drugs from the body.

The two reports, appearing in the Lancet medical journal, add to physicians’ concerns that some herbal supplements may have unexpected, harmful effects, especially when combined with potent medications.

Hundreds of thousands of Americans take St. John’s wort to ease depression and anxiety, a practice they often hide from their physicians, surveys show. And people with HIV tend to consume more herbal products than others do, researchers say.

Unlike drugs, herbal products and other dietary supplements do not undergo rigorous pre-market testing in the United States, leaving some questions about side effects and drug interactions unanswered. Indeed, marketers often tout supplements, which the government classifies as foods, as a safe alternative to drugs.

“There’s a misconception by the general public that these [herbal] substances are safe and have no side effects or interactions,” said Stephen Piscitelli, a doctor of pharmacy at the health institute and lead author of the study. “This shows there can be dangerous interactions.”

At the same time, promoters of herbal supplements and other alternative treatments point out that too little is known about the dangers of mixing various pharmaceutical drugs. Indeed, the National Academy of Sciences recently reported that possibly tens of thousands of deaths annually could be attributed to the untoward side effects of mixing medications.

Patients taking an anti-HIV medication are typically advised to avoid a number of other drugs because of adverse interactions. Those drugs include the anti-fungal drug rifampin and the cholesterol-lowering drugs simvastatin and lovastatin.

In their study, the first to test the effects of an herbal remedy on an HIV medication, the researchers gave indinavir to eight HIV-negative adults after they had been on the usual dose of St. John’s wort for two weeks. The blood levels of indinavir were as much as 80% below what they were when the volunteers took the anti-viral drug alone.

John S. James, editor and publisher of AIDS Treatment News, said the finding may help explain why some patients taking adequate amounts of the anti-HIV drugs were not benefiting from them. “The problem of drug failure is very significant and this could be an important contributor to that,” he said.

“The implications for HIV therapy are huge,” said Dr. David Flockhart, a clinical pharmacologist at the Georgetown University Medical Center and an authority on drug interactions. A prominent concern is that inadequate treatment of HIV infection creates opportunities for renegade viral strains that are resistant to the drug to take hold.

The other HIV drugs that researchers say could be similarly diminished by St. John’s wort belong to two broad classes: the protease inhibitors, like indinavir, and the non-nucleoside reverse transcriptase inhibitors, like delavirdine, or Rescriptor.

For AIDS patients, the consequences of taking St. John’s wort and anti-viral medications remain unclear.

Peter McWilliams, a medical marijuana activist and St. John’s wort distributor who is HIV positive, said he takes massive amounts St. John’s wort every day along with anti-viral medications and prescription anti-depressant drugs. The HIV drugs are working so well that the virus is undetectable in his blood, he said.

But he said the new findings should be pursued. “If people [with HIV] are not getting the desired effect from prescription medications, they should stop taking St. John’s wort” and switch to a prescription anti-depressant, said McWilliams, co-author of the 1994 book “How to Heal Depression.”

Doctors and researchers worldwide have previously reported cases suggesting that St. John’s wort can interfere with a variety of medications, lowering blood levels of the anti-clotting drug warfarin and the asthma drug theophylline.

The FDA advisory noted that drugs used to treat heart disease, depression, seizures and certain cancers also may be affected by simultaneous use of St. John’s wort. “Health care providers should alert patients about these potential drug interactions to prevent loss of therapeutic effect of any drug metabolized by the cytochrome P450 pathway,” the advisory said.

In the report on the heart transplant patients, doctors based at University Hospital in Zurich concluded, after ruling out other possible causes, that the herb interfered with cyclosporine.

Both heart patients recovered after they quit the herbal product and received higher doses of cyclosporine or other anti-rejection medications. “Even a folk medicine, previously regarded as safe and well tolerated, can have a potential risk,” the researchers wrote.

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Medication Caution

Researchers at the National Institutes of Health have found that the herbal supplement St. John’s wort interferes with a medication, indinavir, for fighting HIV. Here are HIV medications that the researchers say may be adversely affected by St. John’s wort.

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Protease inhibitors

Crixivan (indinavir)

Orvir (ritonavir)

Invirase (saquinavir, hard gel)

Fortovase (saquinavir, soft gel)

Viracept (nelfinavir)

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Non-nucleoside reverse transcriptase inhibitors

Viramune (nevirapine)

Rescriptor (delavirdine)

Sustiva (efavirenz)