Hormonal Implants

Original article by Tom Leach | Last updated on 25/5/2014
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Introduction

aka Implanon

Lasts 3 years
12% will have heavier bleeding, particularly in the first 6-12 months. This can be alleviated with:

  • Tranexamic acid – 1g/6-8h for up to 4 days – an antifibrinolytic, can reduce menorrhagia by 50%
  • Mefanamic acid – 500mg/8h – an NSAID - antiprostaglandin – taken during periods of heavy bleeding, can reduce menorrhagia by 30%. Is also useful for dysmenorrhoea. Contraindicated in peptic ulcer disease

Implant goes under the skin, usually on the medial aspect of the upper arm

 

Efficacy

Quoted as: >99% effective
Described as: over the three year duration of treatment, <0.1% of women will become pregnant

  • In obese women, the level of etongestrel (the active ingredient) is reduced during the third year, and there may be a risk of pregnancythus replacement or alternative contraception should be sought after 2 years
 

Mechanism

  • Prevents ovulation
  • Thickens cervical mucous
  • Prevents proliferation of the endometrium, making implantation difficult. 
 

Side effects

  • Acne
  • Breast tenderness
  • Mood swings
  • Changes in libido
  • Infection
    • Small risk of local infection at the implant site
  • Affect on periods – can make them shorter, longer, heavier or lighter, and the response is unpredictable. If bleeding is particularly heavy or persistent, it can be treated with...
 

Benefits over oral POP

More likely to inhibit ovulation, thus:

Also, no interaction with non-enzyme inducing antibacterials

 

Prescribing and Administration

Can be fitted at any point during the menstrual cycle

  • If fitted in the first 5 days is immediately effective
  • If fitted at any other time, another form of contraception (e.g. condoms) will need to be used first

Fitting the implant

  • Fitted on the medical aspect of the upper arm
  • Goes just under the
  • Local anaesthetic given to numb the area
  • Feels similar to an injection
  • Area may be sore for 2-3 days after. The implant can be felt under the skin

Removing the implant

  • Can be removed at any time, should be removed after 3 years
  • Normally just done in clinic by a GP / nurse
  • Local anaesthetic applied, a small inscision is made, and the implant removed
  • In some patients, the implant may be difficult to feel, and these patients will need to be referred to have it removed via guided USS.
  • If the patient intends to carry on using implants as contraception, a further implant can be fitted at the same time as the old one is removed.
  • After permanent removal – fertility returns quickly. Advise the patient pregnancy can occur before periods have returned to normal.

After pregnancy

  • Can be fitted on or before day 21 after to birth to provide immediate protection
  • If fitted after 21 days, additional contraception (e.g. condoms) will have to be used for 7 days

After abortion / miscarriage

  • Can be fitted immediately for immediate protection
 

Drug Interactions

Enzyme inducting drugs

  • E.g. St John’s Wort
  • TB, epilepsy and HIV medications
  • If the patient also takes any of these, it is recommended to use additional contraception (e.g. condoms) for the duration of the treatment and for 4 weeks after

Unlike some other forms of contraception, the implant is not affected by diarrhoea, vomiting or antibiotics.