Is Mirena (levonorgestrel-releasing intrauterine system) a good option for a patient with endometriosis who has been using Myfembree (relugolix) for 2 years and had successful removal of endometriosis lesions prior to starting Myfembree?

Mirena (LNG-IUS) for Endometriosis Management After Myfembree and Lesion Removal

Mirena (levonorgestrel-releasing intrauterine system) is an excellent option for endometriosis management in a patient who has completed 2 years of Myfembree therapy following successful surgical removal of endometriosis lesions.

Rationale for Transitioning to Mirena

Mirena offers several advantages for this specific patient scenario:

1. Continuous Local Hormone Delivery:

   • Mirena releases levonorgestrel directly into the endometrial cavity, providing localized progestin effects that can suppress endometriosis symptoms 1
   • The levonorgestrel induces endometrial glandular atrophy and decidual transformation, which helps prevent recurrence of endometriosis symptoms 1

2. Proven Efficacy for Endometriosis:

   • Mirena has demonstrated effectiveness in relieving pelvic pain symptoms caused by peritoneal and rectovaginal endometriosis 1
   • It reduces the risk of recurrence of dysmenorrhea after conservative surgery, which is particularly relevant for this patient who had complete removal of endometriosis lesions 1

3. Long-Term Solution:

   • Mirena provides up to 5-7 years of continuous therapy 2, 3
   • Recent studies have shown the 52-mg LNG-IUS maintains efficacy for up to 8 years 3

Advantages Over Continuing Myfembree

While Myfembree (relugolix/estradiol/norethisterone acetate) has been effective for this patient, transitioning to Mirena offers several benefits:

1. Localized vs. Systemic Effects:

   • Mirena primarily acts locally in the uterus with minimal systemic effects 1
   • Myfembree works systemically through GnRH receptor antagonism 4, 5

2. Bone Health Considerations:

   • Long-term use of Myfembree may cause some bone mineral density loss (though minimal with the combination therapy) 5
   • Mirena has minimal impact on bone mineral density 3

3. Convenience:

   • Mirena eliminates the need for daily oral medication compliance 2
   • Once inserted, it provides continuous therapy for 5-7 years 2

Expected Outcomes with Mirena

The patient can expect:

1. Menstrual Changes:

   • 70-90% reduction in monthly blood loss after the first year 1
   • 20-30% chance of amenorrhea, which is advantageous for dysmenorrhea management 1

2. Pain Management:

   • Significant reduction in endometriosis-associated pain, particularly dysmenorrhea 1
   • Potential improvement in dyspareunia and dyschezia, though more research is needed 1

3. Long-term Protection:

   • Reduced risk of endometriosis recurrence following surgical removal 1
   • High contraceptive efficacy with Pearl Index of 0.28 for years 6-8 of use 3

Important Considerations

1. Timing of Insertion:

   • Insertion can be performed at any point in the menstrual cycle when pregnancy has been excluded 2
   • Consider scheduling insertion while still on Myfembree to maintain hormonal suppression

2. Potential Side Effects:

   • Initial irregular bleeding is common but typically improves over time 2
   • Other possible side effects include headache, breast pain, and abdominal pain 6

3. Follow-up:

   • Schedule follow-up 4-6 weeks after insertion to check placement and address any concerns
   • Annual follow-up thereafter to monitor symptoms and IUD position

Caveats and Precautions

1. STI Protection:

   • Mirena does not protect against sexually transmitted infections 2, 6
   • Condom use is recommended if STI risk is present 2

2. Contraindications:

   • Current purulent cervicitis, active gonorrhea/chlamydia, current PID, pregnancy, or uterine anomalies that distort the cavity would contraindicate use 2
   • Perform appropriate screening before insertion

3. Rare Complications:

   • Very rare cases of endometrial adenocarcinoma have been reported with LNG-IUS use 7, though this is extremely uncommon and the benefits typically outweigh this risk

In conclusion, Mirena represents an excellent transition option for this patient who has completed Myfembree therapy following successful endometriosis lesion removal. It offers localized hormone delivery, long-term symptom management, and convenience while potentially reducing the risk of endometriosis recurrence.