The sexuological impact of hormonal contraceptives based on their route of administration

Evidence on the effects of hormonal contraceptives on female sexuality is conflicting. We enrolled 556 women, divided into six groups: two composed of subjects using a combined hormonal contraceptive (COC) containing 0.020 ("COC20") and 0.030 ("COC30") mg of ethynyl estradiol (EE), "natural", using COC containing 1.5 mg of estradiol (E₂), "ring", using a vaginal ring releasing each day 0.015 mg of EE + 0.120 of etonogestrel, "subcutaneous", using a progestin only subcutaneous contraceptive implant releasing etonogestrel and "controls", using no hormonal contraceptive methods. The subjects were required to answer to the McCoy female sexuality questionnaire and were subjected to a blood test for hormonal evaluation. An ultrasound evaluation of the dorsal clitoral artery was also performed. The higher McCoy sexological value were recorded in the subdermal group; significant differences were recorded among the groups in terms of hormone distribution, with the higher levels of androstenedione in subdermal and control groups. The ultrasound evaluation of dorsal clitoral artery shows a significative correlation between pulsatility and resistance indices and orgasm parameters of McCoy questionnaire. The recorded difference in the sexual and hormonal parameters among the studied hormonal contraceptives may guide toward the personalization of contraceptive choice.

LC-MS/MS method for determination of megestrol in human plasma and its application in bioequivalence study

A rapid and highly selective liquid chromatography-tandem mass spectrometric (LC-MS/MS) method for the determination of megestrol in human plasma was described using medrysone as internal standard (IS). Blood samples were collected from 20 healthy volunteers after oral administration of 160 mg megestrol acetate dispersible tablets. The analytes were extracted by liquid-liquid extraction procedure and separated on a hanbon lichrospher column with the mobile phase of methanol and water containing 0.1% formic acid and 20 mmol/L ammonium acetate (5:1, v/v). Positive ion electrospray ionization with multiple reaction-monitoring mode (MRM) was employed by monitoring the transitions m/z 385.5-325.4 and m/z 387.5-327.4 for megestrol and medrysone, respectively. Under the isocratic separation conditions, the chromatographic run time was approximately 2.54 min for megestrol and 2.59 min for medrysone. The calibration curve range was from 0.5 to 200.0 ng/mL. The inter-batch and intra-batch precision and accuracy were less than 5.2% relative standard deviation (RSD) and 6.4% relative error (RE). The proposed method was successfully applied in the bioequivalence study of megestrol acetate dispersible tablets.

Nomegestrol acetate, a novel progestogen for oral contraception

Nomegestrol acetate (NOMAC) is a potent, highly selective progestogen, which is structurally similar to 19-norprogesterone and characterized as a full agonist at the progesterone receptor, with no or minimal binding to other steroid receptors, including the androgen and glucocorticoid receptors. In animal models, NOMAC demonstrated moderate antiandrogenic activity and strong antiestrogenic activity. In clinical studies, the progestogen was associated with effective suppression of gonadotropic activity and ovulation in premenopausal women, and a neutral impact on hemostasis, lipids, and carbohydrate metabolism. In normal and cancerous human breast tissue, NOMAC has shown favorable effects on estrogen metabolism, and in human breast cancer cell lines in vitro, it does not stimulate cell proliferation. The pharmacologic profile of NOMAC suggested that it would be well suited for combination with a physiologic estrogen in a combined oral contraceptive (COC), with the aim of achieving effective contraception with good cycle control and a favorable safety profile. A monophasic COC containing NOMAC 2.5mg and 17β-estradiol (E2) 1.5mg, administered in a 24/4-day regimen, is currently under clinical investigation. In a phase III study, NOMAC/E2 provided consistent and robust ovulation inhibition, with contraceptive effects that compared favorably with those of drospirenone 3mg/ethinyl estradiol (EE) 30 μg. Investigators for a second phase III study reported less overall impact with NOMAC/E2 on hemostatic, lipid, inflammatory, and carbohydrate metabolism parameters than with levonorgestrel 150 μg/EE 30 μg. These clinical findings are promising; however, full publication of results from the pivotal phase III trials of NOMAC/E2 is pending.

[Nomegestrol acetate: clinical pharmacology]

Progestogens are used in clinical practice in some conditions. Their effects depend on their chemical structure, pharmacokinetics, pharmacodynamics, with important differences among various progestogens. Generally, progestins are classified according to their parent molecule, of which often they keep some features. Derivatives of 19-nor-progesterone are characterized by high selectivity of action on progestin receptor. In particular, nomegestrol acetate (NomAc) shows an important progestational potency, neutral gluco-lipid profile, and antigonadotropic activity. It is used for treating menstrual cycle disorders and for hormone replacement therapy in menopause in association with an estrogen. In future, thanks to its antigonadotropic activity, NomAc will be used in estroprogestin combinations in fertile women, thus taking advantage of its tolerability profile and obtaining numerous non-contraceptive benefits as well.

Megestrol-induced Cushing syndrome

OBJECTIVE

To report a case of Cushing syndrome associated with megestrol acetate therapy in a patient with renal insufficiency.

SUMMARY

A 17-year-old boy with renal insufficiency due to unilateral renal agenesis developed Cushing syndrome and worsening of his renal function after megestrol acetate therapy. The diagnosis was based on clinical and analytical evaluation.

DISCUSSION

Megestrol acetate is indicated for the treatment of cachexia associated with AIDS and malignancy. Due to its glucocorticoid activity, megestrol use has resulted in the occurrence of Cushing syndrome in both patient groups. We report the case of a young patient with renal insufficiency due to unilateral renal agenesis who developed Cushing syndrome two months after administration of high-dose (900-mg/d) megestrol acetate for an eating disorder.

CONCLUSIONS

The risk of megestrol-induced Cushing syndrome, especially with high doses of the medication, should be considered as a possible adverse effect in patents with renal insufficiency.

Pharmacokinetic evaluation of two different formulations of megestrol acetate in patients with advanced malignancies

The bioequivalence of two megestrol acetate formulations, 160-mg "tablets" and 160-mg "sachets," was investigated in a single-dose, open-label, balanced-for-sequence cross-over study involving 12 advanced-cancer patients. The observed plasma megestrol-acetate time course obtained with both formulations was consistent with the literature data. The main source of variability in the pharmacokinetic parameters was intersubject variability; drug formulation played only a minor (and nonsignificant) role. The width of the 90% confidence interval of the area-under-the-curve (AUC) ratio (sachets: tablets) computed according to Schuirmann (0.9-1.4) was mainly due to the presence of a single outlier, showing an AUC ratio of 2.7. The trend to higher bioavailability of the new formulation was not significant, especially as compared with the dose-response data reported in the literature.

Pharmacologic evaluation of megestrol acetate oral suspension in cachectic AIDS patients

The objective of our study was to define the pharmacokinetics and pharmacodynamics of megestrol acetate in patients with human immunodeficiency virus (HIV) infection. A new suspension formulation of megestrol acetate (40 mg/ml) was administered as a single oral dose of 800 mg per day in an open label pharmacokinetic study for 21 days. On day 21 of therapy, patients were evaluated for changes in body weight and plasma samples were obtained for steady-state pharmacokinetic analysis. Ten HIV-infected men with an involuntary weight loss of > 10% baseline were evaluated. A high degree of interpatient variability in megestrol acetate pharmacokinetics was observed, with an 8- and 5-fold range in the rate and extent of absorption, respectively. All patients reported an increase in appetite, and 8 of 10 patients gained weight by 3 weeks; the median change in weight in all patients at 3 weeks was 1.8-kg gain (range: 2.3-kg loss to 6.4-kg gain). The two patients who did not gain weight had the lowest area under the curve (AUC), Cmax, and Cmin values. A statistically significant correlation between the ratio of body weight at 3 weeks/initial weight (weight index) and the percentage of the 24-h dosing interval that megestrol acetate concentrations exceeded a 300-ng/ml threshold was observed. These data indicate variable levels of systemic exposure to drug following a fixed dose of a suspension formulation of megestrol acetate. Increase in weight during the early stages of megestrol acetate therapy is related to the extent of in vivo drug exposure above a threshold concentration.(ABSTRACT TRUNCATED AT 250 WORDS)

Enzyme immunoassay for nomegestrol acetate in human plasma

Currently available chromatographic assays of the progestative drug nomegestrol acetate in human plasma are not suitable for monitoring drug kinetics more than 24 h after clinical dosage. A specific and sensitive enzyme immunoassay was therefore developed. A 3(O-carboxymethyl)oxime derivative of nomegestrol acetate was synthesized and coupled to bovine serum albumin in order to raise polyclonal antibodies in rabbits. The enzymatic tracer was obtained by coupling the 3(O-carboxymethyl)oxime derivative to acetylcholinesterase (E.C.3.1.1.7.). HPLC fractionation of human plasma samples followed by enzyme immunoassay revealed the presence of cross-reacting metabolites. An automated procedure of metabolite separation was developed using silica bonded with diol groups (Diol Bakerbond column). This procedure ensured assay specificity. The quantification limit in human plasma was 0.1 ng/ml. Mean repeatability (intra-assay variation) and reproducibility (inter-assay variation) were 9 and 15%, respectively. The enzyme immunoassay allowed monitoring of the kinetics of nomegestrol acetate 144 h after oral administration of a single 5 mg dose. Values for human samples were in excellent agreement with those assayable by HPLC followed by u.v. detection.

Clinical pharmacokinetics of endocrine agents used in advanced breast cancer

Endocrine therapy is important in the treatment of advanced breast cancer. The prototype antiestrogen tamoxifen and the prototype aromatase inhibitor aminoglutethimide have been in clinical use for more than 2 decades, as have synthetic progestin derivatives. Currently, several novel antiestrogens and aromatase inhibitors are used to treat breast cancer. This paper reviews the present knowledge of the clinical pharmacokinetics of these drugs. Drug monitoring in plasma and other body fluids has been improved over recent years by the introduction of sensitive and specific high performance liquid chromatography and gas chromatography-mass spectrometry methods. However, we still lack information on such basic pharmacokinetic parameters as the bioavailability of several of these drugs. It is important to study not only plasma but also tissue drug concentrations.

Adrenal steroids as parameters of the bioavailability of MA and MPA

Serum levels of cortisol (C), androstenedione (A), dehydroepiandrosterone (D), estrone (E1) and estradiol (E2) were chosen as parameters to compare the bioavailability of megestrol acetate (MA) and medroxyprogesterone acetate (MPA) in postmenopausal patients with advanced breast cancer. In 36 patients randomized to MPA, the levels of A (13% vs. 19%) and C (6% vs. 8%) were slightly lower than in 36 patients on MA, but D-levels (68% vs. 59%) and E1 or E2, were similar. The correlation between baseline C and A disappeared during treatment. Treatment levels of E1 and E2 were correlated. There was no correlation between individual drug levels and any steroid, indicating a maximal suppression. After ingestion of a single dose of MA or MPA, peak levels were found after 2-3 h for MA and 3-4 h for MPA. Four hours after ingestion, the levels of A and C were similar, 40-60% of baseline values, while D levels remained unaltered. Doubling the dose of either drug did not enhance hormone suppression, indicating that the drug dosage is maximally suppressive. In conclusion, although the median serum MA levels are double those of MPA, suppression of A, C and D is usually similar, with corresponding estrogen levels, demonstrating a comparable and maximal bioavailability. Higher dosages of MA or MPA will not increase their pharmacological effects any further.

Influence of aminoglutethimide on the metabolism of medroxyprogesterone acetate and megestrol acetate in postmenopausal patients with advanced breast cancer

In this study the influence of amino-glutethimide (AG) on the disposition of medroxyprogesterone acetate (MPA) and megestrol acetate (MA) was studied. When 1,000 mg AG daily was supplementally given to six patients on chronic treatment with MPA (1,000 mg/day) or MA (160 mg/day), mean serum levels of progestin were reduced by 74% as compared with control levels (P less than 0.03). AG did not change the blood clearance rate of MPA when the latter was given i.v. This discrepancy between AG's influence on oral and parenteral progestin disposition could be explained by pharmacokinetic properties of the progestins, and our results suggest that AG stimulates the metabolism of progestins. The decrease in MPA and MA serum levels was accompanied by an increase in serum cortisol, sex hormone-binding globulin (SHBG) and testosterone levels. This suggests that AG reduces the biological activity of progestins.

[Study on dissolution rate of injection of microencapsulated compound megestrol acetate]

Dissolution rate of megestrol acetate in the injection of microencapsulated compound megestrol acetate was determined by the first derivative spectrum amplitude method. The experimental results reveal that t50 of the microencapsulated sample (I) is about 60.16 d, while the broken microencapsulated sample (II) is about 15.89 d and the unmicroencapsulated sample (III) about 15.87 d. The difference is regarded as of obvious significance (P less than 0.01). The values of the dissolution rate were linear with the parameters of rabbits and women both in vivo.