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.The Norplant System consists of 6 capsules each containing 36 mg of crystal line levonorgestrel (LNG), for a total dose of 216 mg LNG. The capsules are inserted subdermally in the mid-upper arm, and LNG diffuses continuously through the capsule walls for 5 years. In the United States the Norplant System was approved in December 1990. The initial rate of hormone delivery is about 85 mcg/day, then decreases over the next 9 months to 5 mcg/day, and over the ensuing 9 months to 35 mcg/day. Thereafter, the diffusion rate levels off for the next 3.5 years, averaging around 30-35 mcg/day. Removal results in a drop in the plasma concentration of levonorgestrel to below contraceptive levels within 24 hours and below the detectable limit of .1 pg/ml at 96 hours. Preliminarily data from 402 users over 5 years show improvements of Norplant produced better efficacy in all weight classes and a lowered cumulative rate of 1.1 pregnancies of 100 users. The pregnancy rate for the first year of use is 02., better than for oral contraceptives. Side effects include headache, nervousness, nausea, dizziness, dermatitis, acne, change of appetite, breast tenderness, minimal weight gain, some change in hair distribution, and adnexal enlargement. Adverse reactions include breast discharge, possible cervicitis, musculoskeletal pain, abdominal discomfort, leukorrhea, and vaginitis. More than the usual number of bleeding days occurred in slightly more than one fourth of the patients, prolonged bleeding in 27.6% spotting in 17.1% and amenorrhea in 9.4% of patients. Hyperlipidemic users should be observed for possible low-density lipoprotein elevations. The cumulative discontinuation rate for pregnancy was 3.9 per 100 users; for bleeding irregularities the rate was 25.1 per 100 users, and for other medical results it was about 22.4 per 100 users. Personal reasons for discontinuation accounted for 38.7 per 100 users, equivalent to a cumulative continuation rate of about 30 per 100 users over the 5-year duration.