Pharmacokinetic Interactions between the Hormonal Emergency Contraception, Levonorgestrel (Plan B), and Efavirenz

<table>Mean plasma concentration versus time profile for LNG.  Mean (±SD) levonorgestrel concentration-time profile in 21 healthy volunteers administered alone (red) and after 14 days of pretreatment with efavirenz (blue).</table>

Infectious Diseases in Obstetrics and Gynecology

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Figure 1

Figure 1: Pharmacokinetic Interactions between the Hormonal Emergency Contraception, Levonorgestrel (Plan B), and Efavirenz 