The purpose of this research study is to determine how the body processes key constituents of kratom, an herbal product, and to evaluate whether kratom alters enzymes that break down the drugs midazolam and dextromethorphan in the body. This study will consist of Arm 2 where you will receive a single dose of midazolam plus dextromethorphan alone (part a) and with kratom (part b). Blood will be drawn from an intravenous line following administration of kratom or midazolam plus dextromethorphan. Urine samples will also be collected. You will receive a screening medical exam and will undergo routine blood and urine laboratory tests, as well as a urine toxicology screen, for common drugs of abuse prior to participating in the study.

We are seeking healthy female subjects between the ages of 18-55.

You will receive

up to $700 for completing only Arm 2 + screening visit

You may be eligible to take part in this study if you

• are 18-55 years old and a healthy female;

• are not taking any medications, dietary/herbal supplements, or citrus juices that can interfere with your ability to eliminate the study drugs;

• are 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;

• are willing to abstain from consuming any alcoholic beverages for at least 1 day prior to any study day and during the study day;

• are willing to use an acceptable method of contraception that does not include oral contraceptive pills or patches (such as abstinence, copper IUD, condom);

• have consumed kratom intermittently (not regularly) and are willing to abstain from taking it for at least two weeks prior to beginning the study; and

• have the time to participate.

You will not be eligible to take part in this study if you

• have a chronic illness;

• have a hematologic (blood) disorder;

• have a history of drug or alcohol abuse; 

• have any major psychiatric illness;

are a woman and are pregnant or breastfeeding;

• have a history of allergy to dextromethorphan, midazolam, or related drugs;

• have a history of intolerance or allergy to kratom or opioids;

• have a need for chronic opioid analgesics or an imminent likely need for opioid analgesics (e.g., planned dental or surgical procedure);

• have used opioid analgesics 3 weeks prior to initiation of the study; and/or

• are taking concomitant medications, both prescription and non-prescription (including dietary supplements/herbal products) known to alter the pharmacokinetics of either study drug or kratom constituents.

The Washington State University College of Pharmacy and Pharmaceutical Sciences is conducting this research study through funding provided by the National Institutes of Health.


For more information about this study, please contact:

Deena Hadi, Program Manager

Phone: (509) 368-6692


The WSU Institutional Review Board has reviewed and approved this research project for human subject participation.