MOA

  • primarily inhibiting ovulation

  • thickening of cervical mucus

    • inhibit sperm penetration

Efficacy

  • failure \<0.4% @ 2 years

  • may ocntinue to age 50

  • review q2yrs

  • delay in return to fertility

    • no eveidence reduced fertility long term

    • up to 1 year delay

Starting

  • first injhection D1-5 of normal menstrual cycle

    • no additional
  • any time if not pregnant and no risk of conception

    • additional for 7d
  • if \<D21 postpartum

    • no additional
  • \<5d post miscarriage/abortion

Ongoing:

  • every 12 weeks (+5days)

    • can have up to 2 weeks early
  • late:

    • if up to 14 weeks then change of ovulation low

      • no additional contraceptive
    • of ≥14+1/7:

      • No UPSI:

        • give injection

        • 7 day rule

      • UPSI last 3/7 only:

        • give injection

        • offer ECP

        • 7 day rule

        • Preg test 21/7

      • UPSI last 4-5d only:

        • give

        • ECP - CuIUD

        • no additional if opts for CuIUD

        • preg test 21/7

      • UPSI >5d

        • do not give

        • no ECP

        • barrier for 21d ntil preg neg and then 7d

        • 2x preg tests iniital & @ 21d

Sideeffects

  • bleeding

    • Amenorrhoea 14.4%

    • infrequent bleeding 24.2%

    • spotting 28%

    • prolonged bleeidng 33%

    • 70% of Depot users are amenorrhoeic at 1yr of use

    • unacceptable bleeding:

      • consider STI

      • COC and Mefenamic acid may be effective in management of unacceptable bleeding associated with progestogen-only injectable use

  • Weight change

    • mean weight gain = 3kg @ 2yrs
  • mood change, libido, headache

    • no evidence of causal relationship
  • health concerns

    • doens’t appear to be associated wiht increased risk:

      • stroke, vte, MI
    • BMD

      • small loss

      • usually recovered

      • no evidence on effect of long-term fracture risk

      • FDA black box warning:

        • against use > 2yrs

        • recent evidence suggests warning should be removed

Drug interactions

  • efficacy not reduced with concurrent use of medications

    • including abx and liver enzyme-inducing drugs

    • injection intervals do not need to be reduced