Effects of HIV antiretrovirals on the pharmacokinetics of hormonal contraceptives

Abstract

Objectives To review available information on pharmacokinetic effects of HIV antiretrovirals on hormonal contraceptives.

Methods A PubMed search was conducted from 1964 to 2006 using each antiretroviral generic name and the keywords contraceptive, contraception, ethinyl oestradiol, oestrogen, and progestin. Abstracts from the annual Conference on Retroviruses and Opportunistic Infections and International AIDS Society Conferences from 1998–2006 as well as package product inserts were reviewed for completeness.

Results Antiretroviral regimens containing protease inhibitors and non-nucleoside reverse transcriptase inhibitors may decrease the area under the curve (AUC) levels of steroids released by hormonal contraceptives. Some antiretroviral-hormonal contraceptive pairs do not decrease steroid hormone levels.

Conclusion Pharmacokinetic interactions of antiretrovirals on hormonal contraceptives are specific to the type of antiretroviral and hormonal contraceptive being utilized. HIV-positive women may be counselled to use dual methods of hormonal and barrier contraception to prevent pregnancy with maximal efficacy as well as to reduce possibility of HIV transmission. Oral contraceptives might be administered with non-ritonavir boosted atazanavir or non-ritonavir boosted indinavir without a loss of contraceptive efficacy. Depot medroxyprogesterone acetate may be safe to administer with efavirenz, nevirapine, and nelfinavir. However, further studies are needed to determine the clinical relevance of the interactions between hormonal contraceptives and antiretrovirals and to explore potential dose adjustments to improve contraceptive efficacy.

Key words:

• Hormonal contraceptives
• HIV antiretrovirals
• drug interactions