Pharmacokinetics of ethynyl estradiol: A current view

Newburger, Jerold; Goldzieher, Joseph W.

doi:10.1016/0010-7824(85)90114-3

Cited by 28 publications

(6 citation statements)

References 21 publications

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“…2,15,16 Ethinyl estradiol is metabolized through CYP3Amediated 2-hydroxylation and undergoes conjugation with glucuronic acid and sulfate. [17][18][19] Similarly, norgestimate is extensively metabolized to form metabolites such as 17-deacetyl norgestimate (primary, active circulating metabolite in the plasma), various hydroxylated metabolites, conjugates of these metabolites and others. 20 In contrast, tenofovir is eliminated as unchanged drug in the urine and is neither a substrate, inducer, nor inhibitor of CYP3A enzymes when evaluated in vitro or in a number of pharmacokinetic drug interaction studies in humans.…”

Section: Discussionmentioning

confidence: 99%

Lack of Effect of Tenofovir Disoproxil Fumarate on Pharmacokinetics of Hormonal Contraceptives

Kearney

Mathias

2009

Pharmacotherapy

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Tenofovir DF and norgestimate-ethinyl estradiol are not involved in a clinically significant drug-drug interaction; tenofovir DF did not affect the steady-state pharmacokinetics of norgestimate or ethinyl estradiol, including the concentration at the end of the dosing interval. Both drugs were well tolerated when coadministered. Tenofovir DF is unlikely to affect the pharmacokinetics of hormonal oral contraceptives.

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Section: Discussionmentioning

confidence: 99%

Lack of Effect of Tenofovir Disoproxil Fumarate on Pharmacokinetics of Hormonal Contraceptives

Kearney

Mathias

2009

Pharmacotherapy

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“…Its pharmacokinetics has been described in detail in terms of absolute bio availability [7,8], bioequivalence [9], influence by eth nic groups [10] and smoking habits [11], From time to time reviews were published [12,13] and drug-to-drug interactions were described [14].…”

Section: Discussionmentioning

confidence: 99%

Comparison of Serum Ethinyl Estradiol, Sex-Hormone-Binding Globulin, Corticoid-Binding Globulin and Cortisol Levels in Women Using Two Low-Dose Combined Oral Contraceptives

Hümpel¹,

Täuber²,

Kuhnz³

et al. 1990

Horm Res

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The study included 69 women taking a desogestrel (n = 30)- or gestodene (n = 39)-containing low-dose combined oral contraceptive for at least 3 months. Group size was calculated to detect a difference in mean values of 80% of 1 standard deviation (α = 0.05, β = 0.1). Seven serum samples were obtained up to 4 h, and 1 sample 24 h, after drug intake on 1 day between the 10th and the 21st day of the cycle. The concentrations of sex-hormone-binding globulin (SHBG), corticoid-binding globulin (CBG) and cortisol were measured in a 0- to 4-hour serum pool by radioimmunoassay. Ethinyl estradiol (EE₂) levels were analyzed in single and pooled samples using anti-EE₂-6β-carboxymethyloxime-bovine serum albumin antiserum. The area under the curves (AUC) up to 4 and 24 h and C_maxand t_max were evaluated. Statistical analysis (analysis of covariance) did not reveal a dependence of values on duration of treatment or day of cycle. Both treatments resulted in almost identical values for all parameters evaluated. The mean levels of SHBG, CBG and cortisol were in the range of 186-226nmol/l, 89-93 mg/l and 280- 281 µg/l, respectively. Mean maximum EE₂ levels of 106-129 pg/ml were found 1.6-1.8 h after pill intake and AUC0-4 h accounted for 329-374 pg·h·ml^-1. The recently reported differences in serum EE₂ and CBG levels between two groups of 11 women each treated with desogestrel- and gestodene-containing pills, respectively, could not be confirmed.

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“…Ethinyl oestradiol, the major oestrogen component in oral contraceptives, is metabolized via CYP3 A‐mediated 2‐hydroxylation and undergoes conjugation with glucuronic acid and sulphate [6–8]. Hydroxylation at the 2‐ or 4‐ position has been reported to account for ≈29% of the ingested dose [6, 9].…”

Section: Introductionmentioning

confidence: 99%

Effect of ritonavir on the pharmacokinetics of ethinyl oestradiol in healthy female volunteers

Ouellet

Hsu

Qian

et al. 1998

Brit J Clinical Pharma

161

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Aims To assess the effects of the protease inhibitor ritonavir on the pharmacokinetics of ethinyl oestradiol in healthy female volunteers. MethodsThis was an open-label, single centre study in 23 subjects who received two single doses of oral contraceptive containing 50 mg ethinyl oestradiol on Day 1 (alone) and on Day 29 during concomitant ritonavir. Each subject received 16 days of every 12 h doses of ritonavir from Day 15 through Day 30. Blood samples were collected for serum ethinyl oestradiol concentrations for 48 h after each dose and for plasma ritonavir on Day 29 at 0 and 4 h postdose. Results Statistically significant decreases in ethinyl oestradiol mean C max (−32%) and mean AUC (−41%), and a statistically significant increase in the mean terminal elimination rate constant (+31%) were observed during concomitant ritonavir. The harmonic mean terminal half-life decreased from 17 h to 13 h during concomitant ritonavir. No statistically significant change was noted in t max . The ratios of means (95% confidence intervals) for C max and AUC were 0.682 (0.612-0.758) and 0.595 (0.506-0.694), respectively. The changes in ethinyl oestradiol pharmacokinetics were consistent with an increase in clearance from enzymatic induction of glucuronidation and/or cytochrome P450 hydroxylation. Mean steady-state ritonavir concentrations of 6.5 and 13.4 mg ml −1 were observed at 0 and 4 h postdose, respectively. Conclusions Considering the extent of the decrease in ethinyl oestradiol concentrations, the use of alternate contraceptive measures should be considered when ritonavir is being administered.

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Pharmacokinetics of ethynyl estradiol: A current view

Cited by 28 publications

References 21 publications

Lack of Effect of Tenofovir Disoproxil Fumarate on Pharmacokinetics of Hormonal Contraceptives

Lack of Effect of Tenofovir Disoproxil Fumarate on Pharmacokinetics of Hormonal Contraceptives

Comparison of Serum Ethinyl Estradiol, Sex-Hormone-Binding Globulin, Corticoid-Binding Globulin and Cortisol Levels in Women Using Two Low-Dose Combined Oral Contraceptives

Effect of ritonavir on the pharmacokinetics of ethinyl oestradiol in healthy female volunteers

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