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.