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NCT00131885 · ClinicalTrials.gov registry record · Phase 4
Effects of St. John's Wort on the Oral Contraceptive Hormone Levonorgestrel
A Phase 4 study, sponsored by University of Utah.
- Completed
- Registry status
- Phase 4
- Development phase
- 36
- Enrollment target
NCT00131885: Completed Phase 4 study, sponsored by University of Utah.
NCT00131885 is a Phase 4 study that has completed, run by University of Utah. The registered enrollment target is 36 participants, below the 518-participant average among 9,235 other Phase 4 trials with a reported enrollment target (93% lower). According to ClinicalTrials.gov, the official US trial registry.
The verdict
NCT00131885, a Phase 4 study, has completed, sponsored by University of Utah.
- COMPLETED
- Registry status
- Phase 4
- Development phase
- 36 participants
- Enrollment target
Study Summary
This study will determine the effects of St. John's wort, a common herbal remedy, on metabolism of the female contraceptive hormone levonorgestrel.
Primary Outcome
Pharmacokinetic studies were done between Days 9-12 of the menstrual cycle at Time 1 (baseline, before any treatment with herb or placebo), and at Time 2 (intervention, after treatment with herb or placebo). Serum samples drawn at 0, ½, 1, 1½, 2, 3, 4, 6, 8, 12, 16, and 24 hours, following oral administration of a dose of levonorgestrel. Treatment between the two time periods was with St. John's Wort or placebo herb, beginning after the Time 1 (baseline) and continued for 5 weeks until Time 2.
Interventions
- DRUG Levonorgestrel
- DIETARY_SUPPLEMENT Placebo Control (Placebo Herb)
- DIETARY_SUPPLEMENT St. John's Wort
Trial Details
| Field | Value |
|---|---|
| Enrollment Target | 36 participants |
| Start Date | 2005-08 |
| Est. Completion | 2008-05 |
| Phase | Phase 4 |
What the finished NCT00131885 record still lists
NCT00131885 is an interventional study that assigns participants to a tested intervention. The registry caps enrollment at 36 participants, a relatively small participant target, below the 518-participant average among 9,235 other Phase 4 trials with a reported enrollment target (93% lower).
The record links to 0 conditions, and to 3 interventions - of which Levonorgestrel is the first listed.
NCT00131885 does not publish any study locations in the registry export this page uses.
Frequently Asked Questions
What is clinical trial NCT00131885 about?
NCT00131885 is a clinical study titled "Effects of St. John's Wort on the Oral Contraceptive Hormone Levonorgestrel". This study will determine the effects of St. John's wort, a common herbal remedy, on metabolism of the female contraceptive hormone levonorgestrel.
What is the current status of trial NCT00131885?
This trial is currently completed. It is a Phase 4 study. The enrollment target is 36 participants. The study started on 2005-08. Estimated completion is 2008-05.
What interventions are being tested in trial NCT00131885?
The interventions under investigation include: Levonorgestrel (DRUG), Placebo Control (Placebo Herb) (DIETARY_SUPPLEMENT), St. John's Wort (DIETARY_SUPPLEMENT).
Who is sponsoring clinical trial NCT00131885?
This trial is sponsored by University of Utah, which has 818 total clinical trials registered on ClinicalTrials.gov.
Learn More About Clinical Trials
How this trial's enrollment target compares
Where NCT00131885's enrollment target sits among peer trials
36 1490th of 2000 higher than 495 of 2,000 other Phase 4 trials
participants (enrollment target), bucketed by value
Each bar is a band; taller bars hold more other Phase 4 trials. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count and share, and where it sits relative to this entry.
Source ClinicalTrials.gov registry export · 2026-08-08
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