LEVONORGESTREL SUBDERMAL IMPLANTS - A REVIEW OF CONTRACEPTIVE EFFICACY AND ACCEPTABILITY

Levonorgestrel 6-capsule subdermal implants (Norplant(R)) are an effec tive form of reversible contraception, When implanted under the skin o f the upper arm, they release drug into the circulation at a relativel y constant rate over 5 years. Generally, the cumulative pregnancy rate at the end of 5 years' levonorgestrel implant use is less than 2 per 100 users. The implants provide contraceptive efficacy equivalent to, or better than, that provided by other reversible methods (including o ral contraceptives). Younger women are more likely than older women to become pregnant while using levonorgestrel implants, Bodyweight was p ositively correlated with risk of pregnancy in a number of studies, bu t may not be a factor with the currently available 6-capsule implant f ormulation, Limited data suggest that a new 2-rod levonorgestrel subde rmal system (Jadelle(R)) is as effective as the more extensively studi ed 6-capsule system and has a similar tolerability profile. Fertility returns rapidly after the implants are removed. Use of levonorgestrel subdermal implants is compatible with breast-feeding, In several studi es, discontinuation rates were 2 to 15% during the first year of use; cumulative 5-year discontinuation rates ranged from 22 to 64 per 100 w omen, Despite a substantial incidence of adverse events during therapy , levels of user satisfaction are generally high. Menstrual abnormalit ies (increased or decreased menstrual flow, spotting, irregularity and amenorrhoea) affect most women at some lime during therapy and are th e most frequent reason for discontinuing levonorgestrel implants befor e the end of 5 years' treatment (incidence of 4.2 to 30.7 per 100 user s). Mood changes and headache also may lead to discontinuation. Other reported adverse events include skin reactions (including acne), dizzi ness and weight gain. Serious adverse events (such as stroke, thrombot ic thrombocytopenia and idiopathic intracranial hypertension) have bee n reported during levonorgestrel implant therapy, but the population i ncidence is difficult to calculate and causality is unclear. According to 3 pharmacoeconomic analyses from an institutional or managed-care perspective, all contraceptive interventions result in net cost saving s. It is not clear whether levonorgestrel implants provide greater or smaller economic benefits than combined oral contraceptives. Conclusio n. Levonorgestrel subdermal implants provide effective long term contr aception. Despite a high incidence of menstrual adverse events, overal l levels of user satisfaction are high, and I-year continuation rates are better than those for combined oral contraceptives, Levonorgestrel subdermal implants are a good choice of contraceptive method in women who desire effective contraception, but who are unable to, or prefer not to, comply with an oral regimen.