The effect of isotretinoin on the pharmacokinetics and pharmacodynamics of ethinyl estradiol and norethindrone

Abstract

The small reduction in ethinyl estradiol and norethindrone levels associated with isotretinoin was not associated with any pharmacodynamic changes in our study. The combination of the teratogenic risk of isotretinoin and the large variability of and correlation between oral contraceptive levels and pharmacodynamic measures, however, strongly reinforces the necessity of additional contraceptive methods during concomitant administration of these drugs.

Sitagliptin, a Dipeptidyl Peptidase-4 Inhibitor, Does Not Affect the Pharmacokinetics of Ethinyl Estradiol or Norethindrone in Healthy Female Subjects

“…The finding that the AUC 0–24hr and C max of EE 2 and NET were contained within the predefined comparability bounds indicates that the coadministration of sitagliptin with an oral contraceptive agent will not cause safety issues related to estrogen activity. The pharmacokinetic estimates in this study for EE 2 and NET, whether administered alone or with sitagliptin, were also similar to those reported previously for EE 2 and NET alone 13 …”

“…The biotransformation of NET occurs primarily by reduction followed by sulfate and glucoronide conjugations. The estimated values for t 1/2 from a previous study were 14.2 and 10.3 hours for EE 2 and NET, respectively, after 20 days of administration 13 …”

Preventing and Managing the Side Effects of Isotretinoin

“…There were small but statistically insignificant changes in ethinyl estradiol and norethindrone concentrations. 5 The iPLEDGE program does allow the patient and provider to agree on the use of abstinence as a primary form of contraception. Given the potential consequences of a pregnancy while on isotretinoin, it is advised that the provider feel very comfortable in the maturity of a patient that desires to use this as their form of birth control.…”

What's new in dermatologic therapy

“…Hendrix et al. showed that interactions occur between isotretinoin and oral contraceptive components ethinyl estradiol and norethindrone (42). Some of these interactions lower the circulating blood levels of these hormones, compromising their efficacy at pregnancy prevention.…”