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Biomedical subjects

T B Woutersz

Publications and source records attributed to T B Woutersz.

15 recordsLinked to original sources
PubMed1991

Benefits of oral contraception: thirty years' experience.

A brief overview is presented of some benefits derived during 30 years of oral contraceptive use. Many benefits are significant improvements, and those women desiring to use oral contraceptives have benefited indirectly from lowered doses. Benefits include lowered incidence of endometrial and ovarian cancer, reduced cardiovascular risks, and a decreased incidence of rheumatoid arthritis. It is hoped that such an overview may prove useful during counseling of prospective users for whom oral contraceptives are recommended.

Adult↗
PubMed1991

The NORPLANT system of contraception.

The NORPLANT system is the first new methodology to be introduced in the past 30 years in the field of contraception. It is a subdermal, reversible system of Silastic capsules containing the synthetic progestin levonorgestrel. Advantages and disadvantages are discussed. Compliance-free use and high effectiveness are its main characteristics.

Female↗
PubMed1990

Pharmacokinetic comparison of two triphasic oral contraceptive formulations containing levonorgestrel and ethinylestradiol.

The pharmacokinetics of levonorgestrel (LNG) and ethinylestradiol (EE2) were determined in 24 women (aged 21 to 35 years), following the administration of a single tablet from the second phase of two different triphasic preparations (Triphasil and Trinordiol. Each tablet contained 0.075 mg of LNG and 0.040 mg of EE2. The data were compared to the pharmacokinetics of LNG and EE2 obtained following the oral administration of a hydroalcoholic solution (standard) containing the same steroids and dose. The study consisted of a randomized design in which the three formulations were administered to each of the 24 subjects in a three-period crossover pattern. Blood samples were taken at frequent intervals after dosing. Serum levels of LNG and EE2 were measured by specific radioimmunoassays. The results show that both LNG and EE2 in the Triphasil and Trinordiol tablets are bioequivalent with respect to rate and extent of absorption. Furthermore, LNG, but not EE2, in both tablet formulations was bioequivalent to the solution dose. The serum concentration-time profiles for the three formulations showed that the range of mean peak levels was 2.3-2.8 ng/ml for LNG and 116-159 pg/ml for EE2. These levels were achieved within 2 hours in the majority of subjects. The ranges of mean values calculated for the areas under the curves were 15-16 ng.hr/ml for LNG and 1053-1390 pg.hr/ml for EE2. The ranges of mean values calculated for other pharmacokinetic parameters were: volume of distribution: LNG--1.6-1.8 L/kg, EE2--7.7-9.1 L/kg; clearance: LNG--84-88 ml/hr/kg, EE2--0.67-0.99 ml/hr/kg; half-life: LNG--13-15 hr, EE2--7-12 hrs.

Adult↗
PubMed1987

A low-dose triphasic oral contraceptive.

Controlled clinical investigations of a three-phase, low-dose oral contraceptive combination of levonorgestrel and ethinyl estradiol were conducted at 17 sites in the United States and 60 sites in the United Kingdom. A day 1 start in cycle one with no backup contraception was used. A total of 3546 female volunteers participated in 35,036 cycles. Medication was missed in 2688 (7.7%) cycles. Nine pregnancies were reported for an uncorrected use-effectiveness rate of 0.33 per 100 woman-years. Cycle control was excellent, bleeding irregularities were minimal, and the incidence of side effects was very low. No clinically significant variations in blood pressure means or weight means were observed. Carbohydrate and lipid metabolism studies were limited to 6 months and showed minimal alterations. Subject compliance with the preparation was excellent. It is concluded that this triphasic oral contraceptive with its varying ratios of levonorgestrel and ethinyl estradiol is an effective, predictable, and well-tolerated combination oral contraceptive.

Adolescent↗
PubMed1983

A new ultra-low-dose combination oral contraceptive.

Data were compiled from 17 U.S. sites during a study of levonorgestrel, 0.15 mg, and ethinyl estradiol, 0.03 mg. A total of 1,130 women participated in 11,604 cycles of treatment. Efficacy, cycle characteristics, bleeding irregularities and side effects were studied. Weight and blood pressure means were analyzed with the paired t-test. Subject acceptance of this new combination oral contraceptive was high.

Adolescent↗
PubMed1981

A low-dose combination oral contraceptive. Experience with 1,700 women treated for 22,489 cycles.

A multicenter study was conducted to evaluate the efficacy and acceptability of a combination oral contraceptive containing norgestrel, 0.3 mg, and ethinyl estradiol, 0.03 mg. A total of 1,700 women were treated for 22,489 cycles. Only two pregnancies occurred (Pearl index, 0.20 per 100 woman-years). Cycle control was excellent, and the incidence of breakthrough bleeding, spotting and amenorrhea was low as compared to other reported series of similar low-dose combination contraceptives. No serious side effects were reported, and the drug had no demonstrable adverse effects on weight and blood pressure. The use of this low-dose oral contraceptive appears to provide effective birth control with a high laboratory index of safety and low incidence of side effects.

Adolescent↗
PubMed1977

Low-dose combination oral contraceptives: a controlled clinical study of three different norgestrel-ethinyl estradiol ratios.

Three doses of norgestrel-ethinyl estradiol in altered ratios were investigated in a double-blind, randomized study. The estrogen content was maintained at 20 microng or less, while the progestogen dose was increased in 100-microng increments. Two pregnancies were reported for the lowest dose. No pregnancies occurred in the two higher doses. Each dosage increase improved cycle control and lessened bleeding irregularities. The incidence of patients reporting intermenstrual bleeding was inversely proportional to the doses studied. Dropouts for cycle disturbances followed a similar pattern.

Adult↗
PubMed1976

Three and one-half years' experience with a lower-dose combination oral contraceptive.

Updated data are presented that span 43 cycles of use of norgestrel 0.030 mg as a lower-dose combination oral contraceptive. Active participation by 1,633 women in 20,312 treatment cycles has resulted in a use-effectiveness rate of 0.13 per 100 woman-years. Satisfactory cycle control, minimal menstrual irregularities and a low incidence of side effects produced high acceptability among users. No drug toxicity was demonstrated. The incidence of discontinuance for medical reasons was low.

Adolescent↗
PubMed1975

Comparative studies of the ethynyl estrogens used in oral contraceptives. I. Endometrial response.

Reproductive-age women were given identically prepared mestranol or ethynylestradiol orally for two consecutive 21 day cycles in doses ranging from 50 to 100 mug per day. Endometrial biopsies were obtained at the end of the second cycle and assessed for estrogenic effect. At these dose levels and with this treatment regimen, no differences could be detected between doses or between drugs, indicating that a plateau in endometrial response was reached.

Adult↗
PubMed1975

Comparative studies of the ethynyl estrogens used in oral contraceptives. II. Antiovulatory potency.

The occurrence or inhibition or ovulation was inferred from the plasma progestin level measured in the last week of 430 control cycles and of 4,638 cycles from fertile women receiving various antiovulatory steroids, singly and in combination. The substances tested included: mestranol and ethynylestradiol (EE) of homogeneous bioavailability, used alone in a range from 50 to 100 mug per day; these same dose levels combined with various progestins; and finally various proprietary combination and sequential low-dose regimens undergoing clincial trials. Statistical analysis showed ethynylestradiol and mestranol alone to be equipotent over the tested range, although at 50 mug per day superiority of mestranol over EE was suggested. Two preparations of EE at 50 mug per day, one of them a sequential with dimethisterone, showed different potency. At 50 mug per day no estrogen, alone or with a sequential progestin, reached a satisfactory level of effectiveness. However, very small amount in the range of 20 to 40 mug per day were highly effective when combined with quantities of various 19-nor progestins which by themselves are well below the antiovulatory level. This indicated that a synergism exists between these two classes of compounds insofar as their antiovulatory effect is concerned, thus explaining the high contraceptive effectiveness observed with very-low-dose combination regimens.

Adult↗
PubMed1975

Profile of a new low dose combination estrogen and progestogen oral contraceptive: a review of nine clinical studies.

A new low dose oral contraceptive containing norgestrel 0.3 mg + ethinyl estradiol 0.030 mg was studied by nine investigators in 1287 women during 11,085 treatment cycles, representing 852 woman-years of usage. The preparation was administered on a cyclic basis -- i.e., tablets were taken for 21 days and then omitted for the last seven days of each cycle. Only one woman conceived, giving a use-effectiveness of 0.12/100 woman-years of treatment. Menstrual irregularities were increased slightly from the pretreatment experience, common side effects usually associated with hormonal therapy were minimal, and the product was highly acceptable to most of the women studied. No drug toxicity was demonstrated, and no malignancy of breasts or pelvic organs, no cardiac, pulmonary, hepatic, or renal disease, and no pulmonary emboli or cerebrovascular disease was reported. The incidence of dropout for medical reasons was 8.9%.

Adolescent↗
PubMedDate not supplied

Five-year, multicenter study of a triphasic, low-dose, combination oral contraceptive.

A total of 4,342 women received a triphasic oral contraceptive combination containing levonorgestrel and ethinyl estradiol (Triphasil in the United States, Trinordiol in Europe) over a 5-year period, for a total of 70,282 cycles. Medication was begun on day 1 in the first cycle, with no backup contraception, and consisted of levonorgestrel (LNg) 50 micrograms + ethinyl estradiol (EE2) 30 micrograms for 6 days, LNg 75 micrograms + EE2 40 micrograms for 5 days, and LNg 125 micrograms + EE2 30 micrograms for 10 days. Twelve pregnancies occurred during the study, resulting in a Pearl Index of 0.22. Medication was missed in an overall total of 5,067 cycles (7.2%), and 9 of the 12 pregnancies were attributed by the investigators to misuse of the drug, resulting in a corrected Pearl Index of 0.06. Cycle control was excellent, bleeding irregularities were minimal, and the incidence of adverse experiences was low (generally less than 1% of total cycles). The results indicate that this triphasic combination, given in pharmacologic doses that are patterned after normal cycles, is a predictable, efficacious, well-tolerated, and accepted means of oral contraception.

Adolescent↗
PubMedDate not supplied

A two-year clinical study of the effects of two triphasic oral contraceptives on plasma lipids.

OBJECTIVE: Oral contraceptive formulations can alter plasma lipid and lipoprotein levels; however, lower-dose triphasic tablets show only minimal metabolic effects during 6 or 12 cycles of use. Involvement of lipids in chronic cardiovascular conditions, plus long-term use of oral contraceptive tablets, prompted this first 24-cycle study of the effect of triphasic formulations on young women. METHODS: 69 women assigned randomly to an ethinyl estradiol/levonorgestrel formulation (Triphasil) or an ethinyl estradiol/norethindrone formulation (Ortho 7/7/7) and 25 control women (no hormonal contraception) had blood sampled for lipids and lipoproteins pre-trial, and at 3- or 6-cycle intervals for 24 cycles. RESULTS: At cycle 24, control women experienced no significant change from baseline in any variable except apolipoprotein B (apo B). Plasma apo B increased 42% (P < .01), reflecting the LDL apo B increase (42%, P < .01). Both combination formulations significantly increased apo B (plasma, VLDL, IDL and LDL); the increases ranged between 47% and 84%. Plasma apo A1 rose (15%, P < .001) in the Ortho 7/7/7 group only. Plasma and LDL triglycerides were increased significantly (P < .001) by the norethindrone product, 43% and 81%, respectively, and plasma and LDL cholesterol, 14% and 28%, respectively. Cholesterol decreased in all other subfractions, including HDL (11%, P < .01). HDL cholesterol decreased significantly in the Triphasil group (8%, P < .05); no other cholesterol subfractions changed significantly. All cycle-24 lipid and lipoprotein values remained well within respective normal ranges. CONCLUSION: Although 2-year exposure to the triphasic oral contraceptive formulations changed the lipid risk factors for cardiovascular disease only within normal ranges, there remains potential for long-term health effects when compounded with other risk factors.

Adolescent↗