Impact of Menstrual Cycle on Antiretroviral Pharmacokinetics in Healthy Women

Impact of Menstrual Cycle on Antiretroviral Pharmacokinetics in Healthy Women

Data suggest that women taking drugs to treat human immunodeficiency virus (HIV) have higher amounts of drugs in their body compared with men taking the same dose of anti-HIV drugs. The reason for this higher drug exposure has not been determined. The primary purpose of this study is to examine whether the pharmacokinetics (factors that determine the amount of drug in the body) of anti-HIV drugs change during different phases of the menstrual cycle in women and ultimately result in higher amounts of drug in the body compared with men. In other words, we plan to examine whether changes in sex hormones throughout the menstrual cycle affect the amount of anti-HIV drugs in women. The antiretroviral drugs atazanavir, ritonavir, tenofovir and emtricitabine will be studied. This study will be conducted in healthy women since HIV may change the pharmacokinetics of anti-HIV drugs.

Inclusion Criteria:

• Healthy, HIV negative, nonsmoking females between 21 and 40 years of age.
• Subjects must be within 20% of their ideal body weight and have a regular menstrual cycle, defined as at least 10 cycles per year occurring approximately every 28 ± 4 days and cycle length varying by not more than 7 days.
• Subjects must be willing and able to provide written informed consent.
• Subjects cannot be breast feeding, pregnant or be taking hormonal contraception within 3 months prior to study enrollment. However, they must agree to use an effective non-hormonal method of contraception during the study.

Exclusion Criteria:

• Subjects receiving prescription or over-the-counter products which may interact with the study medication will be excluded from the study.
• Subjects with a Grade 3 or higher laboratory liver, renal or hematology abnormality as specified below in accordance with the DAIDS Table for Grading the Severity of Adult and Pediatric Adverse Events (DAIDS AE Grading Table) Version 1.0, Dec 2004, will be excluded.