Salivary antipyrine half-life during injectable progestagen contraception
Joshi, J.V.; Gupta, K.C.; Hazari, K.T.; Gokral, J.; Pohujani, S.; Satoskar, R.
Clinical Pharmacokinetics 11(2): 171-175
1986
ISSN/ISBN: 0312-5963 PMID: 3956050 DOI: 10.2165/00003088-198611020-00007Document Number: 344384
Antipyrine pharmacokinetics were studied in 6 healthy women before and 2, 8 and 12 weeks after administering the injectable progestagen (progestin), norethisterone (norethindrone) enanthate 200mg intramuscularly. Additionally, antipyrine kinetics in 5 women who had previously used the injectable contraceptive for 8 to 14 months were compared with values obtained in 14 non-users. Antipyrine was measured in saliva using a spectrophotometric method, following an oral dose of 18 mg/kg bodyweight. In the 6 women studied prospectively the mean salivary antipyrine half-life was 14.91 .+-. 1.5 hours (SEM) before administering the injection, and 13.56 .+-. 0.73 at 2 weeks, 15.13 .+-. 1.86 at 8 weeks and 15.21 .+-. 2.46 hours at 12 weeks after the injection. The mean antipyrine half-life in the 5 long term users of injectable progestagen was 14.21 .+-. 2.53 hours compared with 13.66 .+-. 0.98 hours in non-users. The results of this study suggest that - in contrast to published data on combined oral contraceptives - neither short nor long term use of parenteral norethisterone enanthate in Indian women is associated with significant alterations in antipyrine clearance.