Implanon

Aka: Implanon, Nexplanon, Etonogestrel Drug Implant, Progesterone Implant, Contraceptive Implant

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II. Definition

  1. Subcutaneous inserted Progestin containing rod

III. Background

  1. Duration: Continuous Contraception for 3 years
  2. Progestin: Etonogestrel
  3. Release rate
    1. Initial: 60-70 mcg/day
    2. Tapers to 30 mcg/day
  4. Rod dimensions: (Lenth: 40 mm, Diameter 2 mm)

IV. Efficacy

  1. Nexplanon Failure rate: 1 per 2000 users
    1. Failure rate may be higher if >130% of Ideal Weight
    2. Several medications lower efficacy (see below)
    3. Implanon had a higher failure rate (1 in 1000) attributed to insertion technique

V. Drug Interactions: Medications that lower efficacy

  1. Phenobarbital and other Barbiturates
  2. Phenytoin, Fosphenytoin and other Hydantoins
  3. Carbamazepine
  4. Griseofulvin
  5. Protease Inhibitors
  6. Primidone

VI. Safety

  1. Safe in Lactation
  2. Ovulation resumes within 3 weeks of removal

VII. Adverse effects

  1. Weight gain
  2. Acne Vulgaris
  3. Depression or Emotional lability
  4. Irregular Menstrual Bleeding
    1. Amenorrhea most common
    2. Menorrhagia
      1. Bleeding 50% less with Doxycycline 100 bid x5 days
      2. Weisberg (2006) Human Reproduction 21:295-302 [PubMed]

VIII. Procedure: Insertion (<5 minutes)

  1. No incision needed
  2. Nexplanon comes inn Preloaded applicator
  3. Inserted into subcutaneous skin of arm
  4. Both patient and physician must palpate rod post-insert

IX. Procedure: Removal (<10 minutes)

  1. Infiltrate Local Anesthetic under Implanon
  2. Incision of 2-3 mm at distal tip of Implanon
  3. Nexplanon pushed from proximal end into incision
    1. Consider scraping with scalpel
  4. Make incision through fibrous sheeth around Implanon
  5. Remove by grasping Nexplanon rod with forceps
  6. Pearls for difficult removal
    1. Ultrasound if device cannot be palpated
    2. Middle of implant the only palpable part
      1. Make incision over palpable rod and grasp with vas clamp or curved hemostat

X. Protocol: Switching between contraceptives

  1. Starting Nexplanon
    1. Use pill, patch, ring, or barrier protection for the first 4 days after Implanon insertion
    2. Switch may be made before the scheduled end of use of the prior contraceptive

XI. References

  1. Welsh (2006) New Contraceptives, Lecture, Wyoming, MN
  2. Funk (2005) Contraception 71:319-26 [PubMed]
  3. Prine (2018) Am Fam Physician 98(5): 304-9 [PubMed]

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