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progestin-only implant
Indications:
- prevention of pregnancy
- subdermal etonogestrel-releasing implants are the most effective contraceptives available [1]
- women with a body mass index (BMI) >30 kg/m2; can use a progestogen-only implant without restriction and without a reduction in contraceptive efficacy for the duration of the licensed use (Grade C)
- ok for use with migraine
- can safely be used by women who are breastfeeding
Dosage:/Administration:
- duration of use for the progestogen-only implant is 3 years
- subdermal etonogestrel-releasing implants effective for 5 years [1]
- can be inserted immediately following surgical abortion or (second part of) medical abortion or miscarriage
- inserted at the inner side of the upper arm (non-dominant arm) about 6-8 cm above the elbow crease in the groove between the biceps & the triceps (sulcus bicipitalis medialis)
- appropriate anaesthesia should be injected prior to insertion & removal
- use of prophylactic antibiotics to prevent endocarditis is not recommended
- no routine follow-up is required
Adverse effects:
- overall risk of ectopic pregnancy is reduced when using progestogen-only implants when compared to using no contraception
- there is no evidence of a delay in return of fertility following removal of a progestogen-only implant
- bleeding: 20% of users will have no bleeding, almost 50% will have infrequent, frequent or prolonged bleeding; bleeding patterns are likely to remain irregular
- acne may improve, occur or worsen during the use of a progestogen-only implant
- early discontinuation (up to 43% within 3 years)
- no evidence of causal association
a) weight change, mood change, loss of libido
b) headache, ok for use with migraine
c) venous thromboembolism
d) clinically significant effect on bone mineral density
e) breast cancer risk.
Drug interactions:
- efficacy of a progestogen-only implant is not diminished by non-liver enzyme-inducing antibiotics & that additional contraceptive protection is not required
- see progestin
Mechanism of action:
- prevention of ovulation
- pregnancy rate associated with use of a progestogen-only implant is very low (<1 in 1000 over 3 years)
Specific
etonogestrel implant (Implanon)
General
progestin-only contraceptive
contraceptive implant
References
- Bimla Schwarz E
The Etonogestrel-Releasing Contraceptive Implant:
Why Stop at 3 Years?
NEJM Journal Watch. Oct 20, 2016
Massachusetts Medical Society
(subscription needed) http://www.jwatch.org
- Ali M, Akin A, Bahamondes L et al.
Extended use up to 5 years of the etonogestrel-releasing
subdermal contraceptive implant: Comparison to levonorgestrel-
releasing subdermal implant.
Hum Reprod 2016 Sep 26
PMID: 27671673 Free Article