Recruiting

Early Phase 1

Oregano with MedicationEvaluating the Pharmacokinetics of Oregano and Potential Oregano-drug Interactions Using a Drug Cocktail Approach

Sponsor:

Washington State University

Code:

NCT06693960

Conditions

Interaction

Eligibility Criteria

Sex: All

Age: 18 - 64

Healthy Volunteers: Accepted

Interventions

Oregano

Drug cocktail

Study Details

Brief summary:

The purpose of this clinical trial is to determine how the supplement oregano affects how the body metabolizes pharmaceutical drugs.

Conditions

Interaction

Study ID

NCT06693960

Start date

Sep 26, 2024

Status verified date

Jun, 2026

Completion date

Jan 31, 2027

Anticipated

Primary completion date

Dec 15, 2026

Anticipated

Eligibility Criteria

Sex: All

Age: 18 - 64

Healthy Volunteers: Accepted

Inclusion Criteria:

Between 18-64 years old and healthy
Not taking any medications (prescription and non-prescription) or dietary/herbal supplements that can interfere with study drug pharmacokinetics
Willing to abstain from consuming dietary/herbal supplements and citrus juices for several weeks
Willing to abstain from cannabis/marijuana, hemp, and THC- and CBD-containing products for several weeks
Willing to abstain from consuming caffeinated beverages or other caffeine-containing products the evening before and the morning of the first day of each study arm
Willing to abstain from consuming any alcoholic beverages for at least 1 day prior to any study day and during the study day
Willing to use a secondary method of birth control that does not include the introduction or discontinuance of hormonal-based birth control (such as abstinence, copper IUD, or condoms). Specifically, regardless of the use hormonal-based birth control, a non-hormonal method should be used for the duration of the study and for three weeks following cessation of participation.
Willing to abstain from consuming oregano (as a food additive or otherwise) for the duration of the study
Geographically located within a 40-mile radius of Spokane and have the time to participate

Exclusion Criteria:

Under 18 or over 64 years old
Taking medications or dietary/herbal supplements that can interfere with study drug pharmacokinetics
Have a major illness
Taking medication/supplements for a mineral deficiency
History of intolerance or allergy to oregano or any of the cocktail drugs (caffeine, dextromethorphan, losartan, midazolam, and omeprazole)
Use of cannabis/marijuana, hemp, and CBD- and/or THC-containing products within the last month
Currently using drugs or illicit substances for recreational purposes
Pregnant or nursing
Geographically located outside the 40-mile radius of Spokane and do not have the time to participate
Cannot read and speak English

Study Design

Enrollment

16 participants

Anticipated

Allocation

Non randomized

Intervention Model

Crossover

Primary purpose

Basic Science

Interventions and Outcome Measures

Arms

experimental: Arm 1: oregano alone

6 participants will be administered 180 mg of a well-characterized oregano product. Blood will be drawn via an indwelling venous catheter immediately before and at 0.25, 0.5, 1, 1.5, 2, 3, 4, 6, 8, 12, and 24 hours after administration of oregano. Urine will be collected in multiple jugs for 24 hours.

experimental: Arm 2: drug cocktail alone

16 participants, which may or may not include any number of the original 6 from Arm 1, will be administered an oral drug cocktail consisting of caffeine (100 mg), dextromethorphan (30 mg), losartan (25 mg), midazolam syrup (2 mg), and omeprazole (20 mg). Blood and urine will be collected in the same manner described in Arm 1.

experimental: Arm 3: acute oregano + cocktail

The same 16 participants will be administered the oregano product and the drug cocktail. Blood and urine will be collected in the same manner described in Arm 1.

experimental: Arm 4: chronic oregano + cocktail

The same 16 participants will self-administer the oregano product at home for 5 consecutive days. On day 6, participants will return to the study setting, where the procedure described in Arm 3 will be repeated.

Interventions

Oregano

Oil of oregano administered as a softgel (180 mg).

Drug cocktail

Oral drug cocktail consisting of caffeine (100 mg), dextromethorphan (30 mg), losartan (25 mg), midazolam syrup (2 mg), and omeprazole (20 mg).

Primary outcome measure

Midazolam Area under the plasma concentration vs. time curve (AUC) ratio [ Time Frame: 0-24 hours ]

Central Contacts and Locations

Central contacts

Mary F Paine, RPh, PhD

509-358-7759 mary.paine@wsu.edu

Locations

Washington State University College of Pharmacy and Pharmaceutical Sciences

Recruiting

Spokane, Washington, United States, 99202

Contacts

Mary F Paine, RPh, PhD

509-358-7759 mary.paine@wsu.edu

Principal Investigator:

Mary F Paine, RPh, PhD

More Information

Sponsor

Washington State University

Last update posted

Jun 4, 2026

Last verified

Jun, 2026

Keywords

pharmacokinetics
drug interaction
natural products
oregano
cytochrome P450
cocktail

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-10. This information was provided to ClinicalTrials.gov by Washington State University on 2026-06-04.