The objectives of this study are:

• To investigate if the endogenous cholesterol metabolite, 4beta-OHcholesterol could be used as a marker for induction of cytochrome P450 (CYP) 3A4.
• To compare 4beta-OHcholesterol with midazolam as a marker for induction of CYP3A4.

Inclusion Criteria:

1. Females and males.
2. Age of 18 and above.
3. Caucasians.
4. Healthy as assessed by medical history and examination by principal investigator or delegated personnel.
5. Accept to refrain from herbal drugs, natural preparations, and grapefruit juice 48 hours before and during the study period.
6. Accept to completely refrain from alcohol during day -1 to 1 and R14-R16. During the rest of the study moderate alcohol use is permitted (equal to 1 glass of wine or 1 beer per day).
7. Women of childbearing age should accept using a reliable barrier contraceptive method throughout the study.
8. Women of childbearing age should have a negative pregnancy test at the screening visit.
9. Capable of following given instructions.
10. Has given written informed consent after receiving both oral and written study information.

Exclusion Criteria:

1. Predisposal to allergic drug reactions.
2. Anamnestic and/or visual signs of infection.
3. Women are not allowed to use oral hormone-based contraceptives 2 weeks before start of study and during the study.
4. Participation in another study within one month before entering the present study.
5. Intake of any other drug that can influence the enzyme activity of CYP3A4.
6. Pregnancy.
7. Breast-feeding.
8. A history of liver disease.