Clinical Manual > ARV Therapy > Antiretrovirals and Oral Contraceptives

Antiretroviral Medications and Oral Contraceptive Agents

July 2006; updated July 2007

Chapter Contents

Background

References

Table 1. Interactions between Antiretroviral Agents and Oral Contraceptives

Background

This chapter highlights the interactions between currently available antiretroviral agents and oral contraceptives.

The oral contraceptives ethinyl estradiol and norethindrone may interact in complex ways with protease inhibitors (PIs) and nonnucleoside reverse transcriptase inhibitors (NNRTIs). The mechanism of these interactions may be multifactorial and includes the activity of these agents on cytochrome P450 enzymes. Pharmacokinetic studies have shown changes (either increases or decreases) in levels of ethinyl estradiol and norethindrone in women who are taking certain PIs or NNRTIs. Other studies have shown decreases in levels of amprenavir (a PI) in women taking oral contraceptives.

The clinical significance of these drug interactions has not been evaluated thoroughly, but may cause oral contraceptive failure or antiretroviral failure, or medication toxicity, depending on whether drug levels are lowered or raised by the interacting drug.

Table 1 summarizes the available pharmacokinetic data. A more comprehensive review of oral and nonoral contraceptives for HIV-infected women can be found in the chapter Care of HIV-Infected Pregnant Women .

Table 1. Interactions between Antiretroviral Agents and Oral Contraceptives

Antiretroviral Agent	Pharmacokinetic Changes with Oral Contraceptives	Comments
Key to abbreviations: EE = ethinyl estradiol; NE = norethindrone; AUC = area under the curve (drug concentration); C _min = minimum concentration; C _max = maximum concentration. Adapted from U.S. Department of Health and Human Services. Guidelines for the Use of Antiretroviral Agents in HIV-1-Infected Adults and Adolescents . October 10, 2006.
Protease Inhibitors
Atazanavir (ATV, TAZ, Reyataz)	EE AUC increased 48% NE AUC increased 110%	Use lowest effective dose of each OC component and monitor for adverse effects. Consider alternative methods of contraception to avoid OC adverse effects.
Fosamprenavir (FPV, Lexiva), Amprenavir (AMP, Agenerase)	C _min of EE/NE increased 32-45%; no significant change in AUC Amprenavir AUC decreased 22% and C _min decreased 20%	To avoid risk of ARV failure, do not coadminister amprenavir or fosamprenavir with OCs. Consider alternative methods of contraception.
Indinavir (IDV, Crixivan)	EE AUC increased 24% NE AUC increased 26%	No dose adjustment is recommended.
Lopinavir/ritonavir (LPV/r, Kaletra)	EE AUC decreased 42% NE AUC decreased 17%	Use of alternative or additional method of contraception is recommended.
Nelfinavir (NFV, Viracept)	EE AUC decreased 47% NE AUC decreased 18%	Use of alternative or additional method of contraception is recommended to avoid contraceptive failure.
Ritonavir (RTV, Norvir)	EE AUC decreased 40%	Use of alternative or additional method of contraception is recommended to avoid contraceptive failure.
Saquinavir (SQV, Invirase, Fortovase)	No data available regarding effect of SQV on EE or NE levels SQV kinetics not affected by OC	Until more data are available alternative methods of contraception is recommended.
Tipranavir/ritonavir (TPV/r, Aptivus)	EE C _max and AUC decreased approximately 50%	Use of alternative or additional method of contraception is recommended to avoid contraceptive failure.
Nonnucleoside Reverse Transcriptase Inhibitors
Efavirenz (EFV, Sustiva)	EE levels increased 37% No data available on NE component	Use of alternative method of contraception is recommended to avoid OC side effects.
Nevirapine (NVP, Viramune)	EE AUC decreased 20% NE AUC decreased 20%	Use of alternative or additional method of contraception is recommended to avoid contraceptive failure.

References

U.S. Department of Health and Human Services. Guidelines for the Use of Antiretroviral Agents in HIV-1-Infected Adults and Adolescents . October 10, 2006. Available online at aidsinfo.nih.gov/Guidelines/GuidelineDetail.aspx?GuidelineID=7. Accessed July 3, 2007.

Copyright 2010, the AIDS Education & Training Centers National Resource Center, unless otherwise noted. All rights reserved. Email webmaster@aidsetc.org with questions, comments, or problems. See disclaimer for usage guidelines.