title: Pharmacokinetics of norethisterone from two different combination contraceptive pills in Indian women.
abstract: In view of our previous studies that the plasma elimination of norethisterone (NET) from mini pill is faster in low socio-economic group Indian women, the present studies were contemplated to find the least effective dosage of NET from combination pills. Pharmacokinetics of NET were evaluated in a total of twenty women of low socio-economic group taking pills containing NET-acetate (500 micrograms or 1 mg) and ethinyl estradiol (30 or 50 micrograms respectively) on empty stomach. Blood samples were drawn at different time intervals from 0.5 to 24 hr and plasma NET was estimated by a specific radio-immunoassay. In the women taking 1 mg NET-acetate containing pills peak plasma levels ranging from 6.2 to 20.8 ng/ml were observed at 1 hr whereas with 500 micrograms pill they ranged from 2.0 to 6.5 ng/ml and the peak was noted at 4 hr. Pharmacokinetic parameters of NET were more or less comparable between the two pills. The results suggest that pills containing 500 micrograms NET-acetate and 30 micrograms ethinyl estradiol provide adequate levels of NET even in low-socio-economic group women.
authors.affiliation: National Institute of Nutrition, Indian Council of Medical Research, Hyderabad.
authors.forename: B
authors.initials: B
authors.lastname: Sivakumar
authors.forename: K V
authors.initials: KV
authors.lastname: Prasad
authors.forename: P
authors.initials: P
authors.lastname: Ravinder
authors.forename: B A
authors.initials: BA
authors.lastname: Ramalakshmi
authors.forename: B S
authors.initials: BS
authors.lastname: Narasinga Rao
mesh_terms: D003278:Contraceptives, Oral, Hormonal / Q000493:pharmacokinetics*; D005260:Female; D006207:Half-Life; D006801:Humans; D009640:Norethindrone / Q000493:pharmacokinetics*; D011863:Radioimmunoassay
chemical_list: D003278:Contraceptives, Oral, Hormonal; D009640:Norethindrone