Bioavailability of oral micronized progesterone

Diagnosis and treatment of premenstrual syndrome

Abraham GE et al., 1990 · Fertil Steril

Absorption of oral progesterone is influenced by vehicle and particle size

Hargrove JT et al., 1989 · Am J Obstet Gynecol

The oral route of progesterone administration has long been considered impractical because of poor absorption and short biologic half-life. Recent reports suggest that micronization of progesterone enhances absorption and increases serum and tissue levels of progesterone. This study checks serum progesterone levels before and 0.5, 1, 2, 3, 4, and 6 hours after oral administration of 200 mg of progesterone in seven subjects. Progesterone was plain milled, micronized, plain milled in oil, micronized in oil, or micronized in enteric-coated capsules. All patients exhibited a significant increase in serum progesterone levels after oral progesterone administration. Mean peak progesterone levels (30.3 +/- 7.0 ng/ml) (p less than 0.005) were achieved with micronized progesterone in oil at 2.0 +/- 0.3 (p less than 0.05) hours after administration. Four types of oral progesterone had equivalent mean peak elevations and mean times to peak: plain milled, 9.6 +/- 2.5 ng/ml at 4.0 +/- 0.5 hours; micronized 13.2 +/- 2.4 ng/ml at 3.2 +/- 0.4 hours; plain milled in oil, 11.3 +/- 3.0 ng/ml at 4.0 +/- 0.5 hours; and micronized in enteric-coated capsules, 11.2 +/- 3.0 ng/ml at 4.1 +/- 0.7 hours. Contrary to traditional teaching, these data show that significant serum progesterone levels can be achieved by oral administration. Absorption can be significantly improved by the physical characteristics of the progesterone and the vehicle used with oral administration.

Sedative and hypnotic effects of oral administration of micronized progesterone may be mediated through its metabolites

Arafat ES et al., 1988 · Am J Obstet Gynecol

Progesterone and its metabolites were measured in serum extracts by radioimmunoassay and gas chromatography-mass spectrometry, respectively, after ingestion of micronized progesterone by eight postmenopausal women. One subject received 400 mg of micronized progesterone orally that induced a hypnotic state that lasted for approximately 2 hours. Blood samples were drawn periodically from all subjects for measurement of progesterone and its metabolites in serum. Levels of serum progesterone and its metabolites increased significantly from baseline values and reached a peak between 2 and 6 hours after oral progesterone administration. Significant quantities of five compounds (progesterone, 5 alpha-pregnan-3 alpha-ol-20-one, 5 beta-pregnan-3 alpha-ol-20-one, 5 beta-pregnan-3 alpha,20 beta-diol, and 5 beta-pregnan-3 alpha-ol-11,20-dione) that have been reported to possess anesthetic qualities were identified. The sedative and hypnotic effects of oral administration of progesterone may be mediated through those compounds.

Ureteral abnormalities in women with endometriosis

Maxson WS et al., 1986 · Fertil Steril

High-volume intravenous urography was performed in 63 women with surgically proven endometriosis. Subtle abnormalities were found in 15.9% of these women. No patient had urologic symptoms, and there was no evidence of hydroureter or ureteral obstruction on the IVP. Long-term follow-up study will be required to determine whether or not these lesions will progress and cause ureteral obstruction.

Oral micronized progesterone. Bioavailability pharmacokinetics, pharmacological and therapeutic implications--a review

Sitruk-Ware R et al., 1987 · Contraception

Progesterone (P), the natural hormone, binds to its specific receptors to induce specific progestational effects. In addition to this binding, P is able to interfere with the binding sites of other steroids. Therefore the natural hormone exhibits an anti-estrogenic activity, and anti-androgenic activity and also exerts anti-mineralocorticoid effects. For a long time progesterone could not be used in clinical applications because of a rapid liver inactivation after oral administration. An oral micronized preparation of progesterone is now available which produces adequate plasma and tissue levels of progesterone. The preparation reproduces the anti-estrogenic effect of the natural hormone on the endometrium at the dose of 200 mg daily. It also reproduces the anti-mineralocorticoid effect and has no androgenic action. No side effects have been reported as far as lipids profile, coagulation factors and blood pressure are concerned. Therefore oral micronized progesterone appears suitable for hormonal replacement therapy in various areas, essentially postmenopause therapy, premenstrual syndrome, correction of irregular cycles and pregnancy maintenance.

The absorption of oral micronized progesterone: the effect of food, dose proportionality, and comparison with intramuscular progesterone

Simon JA et al., 1993 · Fertil Steril · Free to read

To examine the effects of food ingestion and administered dose on the absorption of oral micronized P (Utrogestan; Besins-Iscovesco, Paris, France) and to compare the bioavailability of intramuscular versus oral routes of administration. Prospective, randomized, open label crossover protocol with 7 days between dosages. Academic institution. Fifteen normal postmenopausal women. All subjects participated in three separate protocols: [1] micronized P (200 mg) or placebo under fasting or nonfasting conditions once daily for 5 days; [2] micronized P (100, 200, or 300 mg) once daily under fasting conditions for 5 days; and [3] micronized P (200 mg) or intramuscular P (50 mg in oil) administered once daily for 2 days. Serum P concentrations were measured in all groups. Concomitant food ingestion increased the area under the serum P concentration versus time curve (AUC0 to 24) and the maximum serum P concentration (Cmax) without affecting time to maximum serum concentration (Tmax) (P < 0.05). Micronized P absorption and elimination were first-order processes and exhibited dose-independent pharmacokinetics between 100 and 300 mg. After intramuscular P, Cmax was higher and Tmax occurred later compared with the oral P preparation. Oral P had lower relative bioavailability (8.6%) than intramuscular P. Absorption of micronized P was enhanced twofold in the presence of food. Both absorption and elimination were dose-independent, dose proportionality being confirmed. Bioavailability of the oral P was approximately 10% compared with intramuscular P.

Bioavailability of progesterone with different modes of administration

Chakmakjian ZH et al., 1987 · J Reprod Med

The bioavailability of micronized progesterone (P) was studied by measuring sequential serum P concentrations after a single bolus of 50-200 mg P given sublingually, orally (capsule and tablet), vaginally and rectally (suppositories) during the follicular phase in a group of normally menstruating women. When compared to other modes of P administration, the area under the curve during the first eight hours was twice as high with the rectal route. With 50 and 100 mg P given sublingually and 100 and 200 mg ingested as tablets, peak levels and area under the curve were twice as high with the higher dosage. The response was more sustained with the higher dosage. All subjects exhibited a significant increase in serum P levels over baseline that persisted for at least eight hours. P levels were still increased over baseline at 24 hours in all subjects after the administration of 100-mg vaginal and rectal suppositories and 200-mg tablets. These findings are in general agreement with previous reports showing that luteal phase serum P concentrations can be reached easily with non-parenteral modes of administering micronized P and that oral P administration could become an attractive alternative to the currently used oral mode of administering synthetic progestins.

Absorption and metabolism of oral progesterone when administered twice daily

Padwick ML et al., 1986 · Fertil Steril

The absorption, metabolism, and clearance of progesterone (P) from the peripheral circulation were investigated in five postmenopausal women after oral administration of 100 mg at 9:00 A.M. and 200 mg at 9:00 P.M. for 5 consecutive days. Mean peak plasma concentrations of P were observed 2 hours after ingestion of both the 100 and 200 mg doses and were 22.7 and 47.7 nmol/l, respectively. Of the three metabolites studied, the plasma concentrations of pregnanediol-3 alpha-glucuronide were most raised by treatment; those of 17-hydroxyprogesterone were least raised. Increases in the plasma levels of 20 alpha-dihydroprogesterone were more sustained than those of P, and the plasma concentrations remained elevated at approximately 20 nmol/l for at least 12 hours after P administration. We conclude that administration of oral P 100 mg in the morning and 200 mg at night increases the circulating concentrations of P and the biologically active metabolite 20 alpha-dihydroprogesterone, and that the duration of these increases is sufficient to evoke progestational responses in responsive end-organs.