This study will determine the effects of St. John''''s wort, a common herbal remedy, on metabolism of the female contraceptive hormone levonorgestrel.

Condition	Intervention	Phase
Menarche	Drug: St. John''''s wort (Hypericum perforatum)	Phase IV

Further Study Details: 

Primary Outcomes: Pharmacokinetic studies between Days 9 and 12 of the menstrual cycle before and during treatment with St. John''''s wort or placebo; ovulation, defined as progesterone levels 3.0 ng/ml at weekly intervals after dosing until menses
Secondary Outcomes: Mean levels of follicle-stimulating hormone, estradiol-17b (E2), luteinizing hormone, inhibin, and glycodelin drawn at weekly intervals until next menses
Expected Total Enrollment:  36

In the last decade, St. John''''s wort has become one of the most commonly used botanicals. Levonorgestrel is a form of progesterone, a female hormone involved in conception. It can be given as both a pill and an injection and is used for contraception and for the treatment of endometriosis. However, evidence suggests that St. John''''s wort may reduce the effectiveness of the contraceptive hormone levonorgestrel. This study will determine whether interactions between St. John''''s wort and levonorgestrel reduce the effectiveness of the hormone. This study will also determine whether a higher dose of levonorgestrel will override the effects of St. John''''s wort.

All participants will receive a single dose of levonorgestrel between Days 9 and 12 of their first menstrual cycle after entering this study. Blood and urine collection will occur immediately after the levonorgestrel is given and every week until participants'''' next menstrual cycle to determine the levels of reproductive hormones in participants'''' bodies.

At the beginning of participants'''' next menstrual cycle, they will be randomly assigned to one of four groups and receive either St. John’s wort or placebo for 6 weeks. Group 1 will receive a placebo; Groups 2 and 3 will receive a standard dose of St. John’s wort (900 mg per day); and Group 4 will receive an increased dose of St. John’s wort (1500 mg per day). After 6 weeks, Groups 1, 2, and 4 will receive 150 mcg levonorgestrel; and Group 3 will receive 225 mcg levonorgestrel. Blood and urine collection will occur immediately after levonorgestrel is given and every week until participants'''' next menstrual cycle.

Ages Eligible for Study:  18 Years   -   30 Years,  Genders Eligible for Study:  Female

Accepts Healthy Volunteers

Criteria

Inclusion Criteria:

• Body mass index (BMI) between 20 and 25
• Regular menstrual cycles for at least 3 months prior to study entry

Exclusion Criteria:

• Current use of foods, herbs, vitamins, over-the-counter supplements, or any medications that could alter pharamcokinetics of other drugs
• Medical contraindications to the use of contraceptives

Please refer to this study by ClinicalTrials.gov identifier  NCT00131885

Utah
      University of Utah, Salt Lake City,  Utah,  84112,  United States; Recruiting

Study chairs or principal investigators

Patricia A. Murphy, DrPH,  Principal Investigator,  College of Nursing, University of Utah   

Study ID Numbers:  R21AT002297
Last Updated:  August 18, 2005
Record first received:  August 17, 2005
ClinicalTrials.gov Identifier:  NCT00131885
Health Authority: United States: Federal Government
ClinicalTrials.gov processed this record on 2005-08-23