Phase I clinical trial of two contraceptive preparations. Norethisterone enanthate (NEN) and norethisterone acetate (NET).

A Phase I Clinical Trial was conducted in 20 fertile Cuban women using for contraception: Norethisterone Enanthate injectable (NEN) and Norethisterone Acetate minipill (NET). Women had daily blood sampling during a control cycle and during the second month of treatment with either drug. Discontinuation rate was very low (1/20). The preovulatory LH and FSH peaks were abolished in all treated women, basal levels remaining unchanged. The incidence of menstrual disorders as amenorrhea, spotting and inter-menstrual bleeding was greater in subjects using NEN than in those on NET. No pregnancy was reported. Blood pressure was unaltered. Renal, hepatic and thyroid function were unchanged. Cholesterol levels were unchanged and triglycerides significantly decreased with both preparations. Women on either NEN or NET underwent OGTT before and after 2 months treatment. In NEN group glycemia was unchanged but insulin levels increased significantly at 120 minutes. In NET group glycemia and insulin levels were significantly increased at all times during post-treatment OGTT. Both forms of Norethisterone were well accepted by this group of women despite menstrual irregularities. Significant changes were found in the group using NET with regard to carbohydrate metabolism.