Diindolylmethane in Healthy Volunteers

PRIMARY OBJECTIVES:

I. Determine the effect of multiple daily dosing with nutritional-grade, absorption-enhanced diindolylmethane (BR-DIM) on the disposition of probe drugs metabolized by cytochrome P4501A2 (CYP1A2) and CYP3A4 in healthy volunteers.

SECONDARY OBJECTIVES:

I. Determine the effect of multiple daily doses of BR-DIM on estrogen metabolites in urine and on activities of CYP2C9, CYP2D6, and P-glycoprotein/OATP.

II. Determine the effect of a single dose of BR-DIM on the disposition of probe drugs that are metabolized or transported by CYP1A2, CYP2C9, CYP2D6, CYP3A4, and P-glycoprotein (P-go).

III. Determine the safety and tolerability of single and multiple daily doses of BR-DIM.

IV. Determine the pharmacokinetics of a single dose of BR-DIM and of the same dose after chronic daily dosing.

V. Determine the pharmacokinetics of a single dose of BR-DIM and of the same dose after chronic daily dosing.

TERTIARY OBJECTIVES:

I. To determine effects of BR-DIM on activities of glutathione-S-transferase (GST), a phase 2 enzyme, in lymphocytes.

OUTLINE: This is a randomized, double-blind study. Participants are stratified according to gender. Participants are randomized to 1 of 2 intervention arms.

Arm I: Participants receive low-dose oral diindolylmethane (BR-DIM) twice daily for 4 weeks.

Arm II: Participants receive high-dose oral BR-DIM twice daily for 4 weeks.

In both arms, participants receive an oral probe-drug cocktail comprising caffeine (CYP1A2), dextromethorphan (CYP2D6), buspirone (CYP3A4), losartan (CYP2C9), and fexofenadine (P-glycoprotein) before randomization and after the first and last dose of BR-DIM.

Blood and urine are collected periodically for pharmacokinetic profiles of BR-DIM and probe drugs.

After completion of study intervention, participants are followed at 1 week.

Criteria:

• Healthy men and women
• Nonsmoker confirmed by urine cotinine test
• No active malignancy
• Life expectancy >= 12 months
• Hemoglobin > 10 g/dL
• Absolute granulocyte count > 1,500/mm^3
• Creatinine < 2.0 mg/dL
• Albumin > 3.0 g/dL
• Bilirubin < 1.8 mg/dL
• AST and ALT < 110 U/L
• Alkaline phosphatase < 300 U/L
• Body mass index =< 30
• Not pregnant or nursing
• Negative pregnancy test
• Fertile participants must use effective nonhormonal contraception
• No acute, unstable, chronic, or recurring medical conditions
• No strict vegetarians or consumption of > 3 medium servings (1/2 cup each) of cruciferous vegetables per week
• Participants who have stopped eating cruciferous vegetables within the past 2 weeks and agree to refrain from eating them for the duration of the study are eligible
• Cruciferous vegetables include broccoli, cabbage (including coleslaw), cauliflower, bok-choy, brussels sprouts, collards, kale, kohlrabi, mustard greens, rutabaga, turnip, and watercress
• No serious drug allergies or other serious intolerance or allergies
• Mild seasonal allergies allowed
• No chronic conditions, including headaches, dysphoria, fatigue, dizziness, blurred vision, insomnia, rhinorrhea, nausea, vomiting, abdominal pain, diarrhea, constipation, menopausal hot flashes/night sweats, or clinically significant premenstrual syndrome
• No serious acute or chronic illness
• No requirement for chronic drug therapy
• No alcohol ingestion within 48 hours of study treatment
• No investigational drugs within the past 3 months
• No prior chemotherapy
• No concurrent regular medications or hormones
• No recent change in medications or dosage of medications
• No concurrent regular supplements or vitamins
• No concurrent over-the-counter medications
• No concurrent grapefruit or its juice