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Following the development and widespread use of oral hormonal contraceptives, it became evident that alternative long-acting delivery systems would be required to improve contraceptive practice in some cultural settings where injectable or subdermal routes of administration are preferred. Nowadays, long-acting contraceptives constitute an important option in family planning services in many parts of the world. Indeed, two long-acting injectable contraceptives containing just a synthetic progestogen (depot-medroxyprogesterone acetate (DMPA) and norethisterone enantate (NET-EN)) have been in clinical practice for more than 20 years. The World Health Organization's (WHO) Special Programme of Research in Human Reproduction, in collaboration with the U.S. National Institute of Child Health and Human Development (NICHD) and universities primarily in developing countries undertook a synthesis programme aimed at producing an improved injectable preparation by developing new derivatives of known steroids. One such compound (levonorgestrel 17-butanoate) is now at the stage of Phase II clinical testing. In addition, the Special Programme has developed and improved once-a-month injectable formulations and assessed their safety and efficacy in different countries worldwide. After large scale clinical testing, at least two progestogen-estrogen combinations have reached the point of introductory trials.

PIP: A survey of recent trials of new injectable hormonal contraceptives, progestogen-only, levonorgestrel esters, and once monthly injectables, follows a brief review of all the experimental long-acting contraceptive modalities, injectables, implants, vaginal rings, and hormone-releasing IUDs. Currently medroxyprogesterone acetate (DMPA) and norethisterone enanthate (NET-EN) are being used by 7 million women. WHO is conducting dose reduction trials and studies of bioavailability in various national populations. Even though a dose of 100 mg DMPA every 3 months has been satisfactory for contraception, 150 mg is still recommended until further pharmacodynamic data are available. Some populations, notably Thais and Mexican women, have higher peaks and more rapid elimination rates of DMPA, while Chinese women show slower elimination and higher blood levels of NET-EN. Extensive studies of new synthetic esters of levonorgestrel have proceeded to Phase II clinical trials with levonorgestrel butanoate. This ester is an effective contraceptive for 3 months at 12.5 mg, or 5-6 months at a dose of 25 or 50 mg. Trials of combined estrogen and progestogen injectables once-monthly have been ongoing for 10 years. The ratio of the 2 components is as important as the amounts. 2328 women from 12 countries participated in trials of DMPA 25 mg-estradiol cypionate 5 mg, and NET-EN 50 mg-estradiol valerate 5 mg. The continuation rate was better than that for 3-monthly progestogen-only injectables, because of less irregular bleeding. A combined injectable called Cyclofem, DMPA 25 mg-estradiol cypionate is being introduced in several countries. The steadily increasing demand for long-acting injectables prompts development of better formulations.

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In three ongoing open studies conducted by 50 investigators in Europe, South America, and New Zealand, 639 subjects followed a new triphasic regimen of gestodene (GTD) and ethinyl estradiol (EE) for 3,020 cycles. One study used GTD + EE only, but in each of the other two studies a comparator oral contraceptive (OC) also was given: norethisterone (NET) + EE in one and desogestrel (DSG) + EE in the other. The objective of all three studies was to assess the efficacy, cycle control, and safety of the triphasic GTD + EE. The following is a report of the interim results. Statistical analysis was performed only on differences between groups in the incidences of bleeding irregularities. During six treatment cycles, subjects either followed the GTD + EE regimen (50 micrograms GTD + 30 micrograms EE for 6 days, 70 micrograms GTD + 40 micrograms EE for 5 days, and 100 micrograms GTD + 30 micrograms EE for 10 days) or took triphasic NET + EE or monophasic DSG + EE. Each cycle concluded with a seven-day hiatus in study medication. No pregnancies occurred with any of the contraceptive preparations (Pearl Index = 0). Compliance was good in all studies and a majority of subjects were still participants at cycle 6. Normal bleeding was reported during 92% of the total evaluable cycles of GTD + EE use. Cycle control with GTD + EE was superior to that with NET + EE or DSG + EE: Breakthrough bleeding occurred in 1.5% of the pooled GTD + EE cycles versus 6.6% of the NET + EE cycles and 2.6% of the DSG + EE cycles; spotting occurred in 4.5% of the GTD + EE cycles versus 9.7% of the NET + EE cycles and 10.3% of the DSG + EE cycles; and breakthrough bleeding plus spotting occurred in 2.1% of the GTD + EE cycles versus 8.1% of the NET + EE cycles and 4.6% of the DSG + EE cycles. Amenorrhea occurred in 2.0% of the cycles with NET + EE, but was reported by only 0.3% of all the subjects given GTD + EE and 0.7% of those given DSG + EE. Cycle length and intensity of bleeding changed little during the use of any of the study preparations. Mean length of withdrawal bleeding during the GTD + EE regimen shortened from 4.5 days (prestudy) to 4.0 days. With each OC, the subjects' mean weight during cycles 3 and 6 differed less than 0.5 kg from baseline values.(ABSTRACT TRUNCATED AT 400 WORDS)

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Two formulations of polylactic and polyglycolic acid microcapsules containing 75 and 100 mg of NET respectively were studied for a 90-day period of anticipated contraceptive effect in two groups of five women. A 200 mg dose of NET preparation was also studied for a 180-day period of anticipated contraceptive effect in 19 women. Alteration in menstrual cycle, with tendency to short bleeding episodes, spotting days, and amenorrhea were the most important collateral effects. In the majority of cases, ovulation was inhibited. No cases of pregnancy were presented. The obtained NET circulating levels were very stable during the period of anticipated contraceptive effect.

PIP: At the Institute of Scientific Investigation of Juarez University of Durango State in Mexico, clinical researchers compared three delivery systems of norethisterone (NET) contraceptive microspheres (biodegradable polymers [e.g., polyglycolic or polylactic acid] containing micronized crystals of NET). In the 6-month system, they injected 800 mg of microspheres containing 200 mg NET intramuscularly into 19 women and then monitored the women for various effects and side effects. Soon after injection, the mean NET level in serum rose to a peak value of about 3 ng/ml and then fell gradually until it was below 0.5 ng/ml at 25 weeks. No pregnancies occurred during this period. Estradiol levels remained well below 100 pg/ml, suggesting inhibition of follicular activity. However, one patient showed an elevation in estradiol at week 16. By 24 weeks, 4 of the 19 women showed signs of the return of follicular activity. Rises in progesterone levels, indicative of ovulation, were not seen in most women during the 6-month period. However, 4 women showed progesterone peaks followed by menstruation in weeks 4, 7, 17, and 23, suggesting that their cycles had begun to return before the end of the 6-month period. 35% of women reported dizziness and nausea. 26% reported nausea. A more serious concern was the disruption seen in the menstrual pattern. 13 women had bleeding and spotting, which continued for 8-30 days in 8 women. In the 3-month system, microspheres containing either 75 or 100 mg NET were injected, each into 5 women. NET levels rose to between 1 and 2 ng/ml and fell to 0.5 ng/ml by week 15. At week 25, they were undetectable. Levels of estradiol remained low for at least 15 weeks as did serum progesterone. No pregnancies occurred. One woman ovulated in week 17. Although no headache, dizziness, and nausea were reported, many of the same disruptions in the menstrual cycle reported in the 6-month study were observed, particularly prolonged cycles, amenorrhea, and spotting. Based on these findings, the researchers deemed the 100 mg for 3 months to be the most safe and effective formulation.

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PIP: Since recent recommendations advocate that smaller doses of estrogen should be used, a combination of .5 mg of norethindrone and .015 mg ethinyl estradiol was tested on 198 patients for a total of 2546 cycles, the longest usage being over 2 years. The women ranged from 15 to 45 years of age, the average age being 28, and the average number of pregnancies, 5.2. The medication was taken daily for 21 days and then stopped for 7. The group was controlled for secondary effects, bleeding, weight changes, and nucleal or hormonal changes. 14.2% stopped taking it because of secondary problems like spotting, nausea, transhormonal bleeding, and depression. The only pregnancy was due to inadequate attention to the prescription by the patient. Tolerance of the medication was quite good overall and no severe difficulties resulted.^ieng

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PIP: Although less distinct than those of the endometrium, the Fallopian tubes show definite changes due to ovarian hormones. The effect of the hormones on the tubes determines certain modifications in their secretions and activities. The estrogens increase the secretions, but progesterone decreases the effect of the estrogens. In the study, a single dose of 200 mgm of norethisterone enanthate was given im on the 6th day of the cycle to 10 patients of fertile age. The effects were studied using conventional histological methods. During the first 6 weeks there was a definite decrease in growth and differentiation of the epithelial cells and gradual recovery toward the end of the 12 weeks of observation. The salpingian mucus in the first 6 weeks indicated a state of rest, similar to that of menopause. This aspect gradually modified itself with the increase in the volume of cells and the appearance of cellular secretions. In the last 2 weeks, cellular hypertrophy, and the appearance of intercalary cells indicated the anatomical and functional recovery of the epithelium. As a possible explanation it was suggested that during the first 6 weeks the action of the estrogens was inhibited, but by the 7th week their proliferative effects became dominant. It is implied that the changes were due to the contraceptive action of norethindrone enanthate.^ieng

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PIP: Norethindrone was administered continuously in daily doses of .35 mg to 74 women suffering from menstrual disorders for 576 cycles. The cases included 39 women suffering from dysmenorrhea (treated for 296 cycles) and 35 women suffering from premenstrual tension (treated for 280 cycles). The symptoms improved or disappeared in 87.2% of the dysmenorrhea cases, and in 93.9% of the premenstrual tension cases; the percentages by number of cycles studied were 90.3% and 95.0%, respectively. Only 1 case of dysmenorrhea worsened. The findings are regarded as conclusive and demonstrating the usefulness of norethindrone in the treatment of these disorders.^ieng

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PIP: A tablet of .35 mg of norethindrone was administered daily and continuously for 6 complete cycles to 30 patients suffering from premenstrual tension syndrome and 5 suffering from functional sterility related to a deficiency of the corpus luteum. In the case of premenstrual tension, particularly good results were obtained in reducing pelvic pains, mastalgia, and headache, especially when related to disorders of the estrogen metabolism. In the sterility cases, 2 patients out of 5 responded to the treatment: 1 was in the 7th month of pregnancy at the time of writing and 1 suffered a spontaneous abortion from unknown causes in the 3rd month of pregnancy. It is concluded that this is a promising treatment, especially for premenstrual disorders.^ieng

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