St. John's Wort for Tobacco Cessation

Cigarette smoking is the single most important preventable cause of morbidity, mortality and excess health care costs in the United States. The prevalence of cigarette smoking among U.S. adults has declined from 42% in 1965 to 20.9% in 2004. However, the overall decline is not occurring at a rate that will meet national health objectives by 2010. Available pharmacotherapies for the treatment of tobacco dependence are not efficacious for all tobacco users and have an overall estimated efficacy of approximately 20% for long-term tobacco cessation. Thus, novel pharmacotherapies for tobacco cessation need to be explored.

Current smokers tend to be younger with less education and belong to a lower socioeconomic status. Tobacco cessation treatments are expensive and often not covered by Medicare, Medicaid, or third party-payers. Our goal is to evaluate novel, safe, acceptable, effective, and inexpensive therapies that will increase tobacco abstinence rates.

The United States Public Health Service (USPHS) guideline recommends nicotine replacement therapy and bupropion as first-line agents for the treatment of tobacco dependence. Bupropion acts by central dopamine and norepinephrine reuptake inhibition. St. John's Wort (SJW), a widely used herbal product to treat mild to moderate depression, shares a similar mechanism of action and is available as a tobacco cessation aid in a number of over-the-counter preparations. While currently approved pharmacotherapies for tobacco dependence cost between $120-$240 per month, SJW is relatively inexpensive ($15 per month) and is well-tolerated. At present, no randomized prospective study of St. John's Wort for tobacco cessation has been published.

We plan to test the efficacy of SJW for tobacco cessation in a randomized, double-blind, placebo-controlled, three-arm, parallel group, dose-ranging clinical trial. We will obtain preliminary data about the efficacy of two different oral doses of SJW for improving tobacco abstinence rates and decreasing symptoms of nicotine withdrawal. All subjects will receive a behavioral intervention during participation in the study. A total of 120 subjects will be recruited into the study and randomly allocated to one of the three groups (groups A, B, and C). Participants in group A will receive SJW 300-mg three times a day for twelve weeks while participants in group B will receive SJW 600-mg three times a day for twelve weeks. Participants in group C will receive a matching placebo for the same duration.

We will conduct this research through the Nicotine Research Program (NRP) at the Mayo Clinic in Rochester, Minnesota. We are uniquely situated for completing this research as more than 7,500 patients have been enrolled in over 75 clinical trials conducted through the NRP. We propose the following specific aims: