Mirena

SIDE EFFECTS

The following serious or otherwise important adverse reactions are discussed in elsewhere in the labeling:

• Ectopic Pregnancy [see WARNINGS AND PRECAUTIONS]
• Intrauterine Pregnancy [see WARNINGS AND PRECAUTIONS]
• Group A Streptococcal Sepsis (GAS) [see WARNINGS AND PRECAUTIONS]
• Pelvic Inflammatory Disease [seeWARNINGS AND PRECAUTIONS]
• Perforation [see WARNINGS AND PRECAUTIONS]
• xpulsion [see WARNINGS AND PRECAUTIONS]
• Ovarian Cysts [see WARNINGS AND PRECAUTIONS]
• Bleeding Pattern Alterations [see WARNINGS AND PRECAUTIONS]

Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice.

The data provided in Table 2 reflect the experience with the use of Mirena in the adequate and well-controlled studies as well as in the supportive and uncontrolled studies for contraception and heavy menstrual bleeding (n=5,091). The data cover more than 12,101 women-years of exposure up to 5 years of use, mainly in the contraception studies (11,761 women-years). The frequencies of reported adverse drug reactions represent crude incidences.

The most common adverse reactions (≥10% users) are alterations of menstrual bleeding patterns [including unscheduled uterine bleeding (31.9%), decreased uterine bleeding (23.4%), increased scheduled uterine bleeding (11.9%), and female genital tract bleeding (3.5%)], abdominal/pelvic pain (22.6%), amenorrhea (18.4%), headache/migraine (16.3%), genital discharge (14.9%), and vulvovaginitis (10.5%). Adverse reactions reported in ≥ 5% of users are shown in Table 2.

Table 2 Adverse Reactions ≥ 5% Reported in Clinical Trials with Mirena

Other adverse reactions occurring in <5% of subjects include alopecia, (partial and complete) device expulsion, hirsutism, nausea, and PID/endometritis.

A separate study with 362 women who have used Mirena for more than 5 years showed a consistent adverse reaction profile in Years 6 and 7 as shown in Table 2. By the end of Year 7 of use, amenorrhea and infrequent bleeding are experienced by 28% and 26% of users, respectively; irregular bleeding occurs in 12%, frequent bleeding in 8%, and prolonged bleeding in 2% of users. In this study, 6% of women reported the adverse event of weight gain; it is unknown if the weight gain was caused by Mirena.

Postmarketing Experience

Adverse Reactions From Postmarketing Spontaneous Reports

The following adverse reactions have been identified during post approval use of Mirena. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

• Arterial thrombotic and venous thromboembolic events, including cases of pulmonary embolism, deep vein thrombosis and stroke
• Device breakage
• Hypersensitivity (including rash, urticaria and angioedema)
• Increased blood pressure

Reported Adverse Reactions From Postmarketing Studies

Assessment of Perforation and Expulsion of Intrauterine Devices (APEX IUD) Study

APEX IUD was a large US retrospective cohort study to assess the impact of breastfeeding and timing of postpartum IUD insertion on uterine perforation and IUD expulsion. The analyses included a total of 326,658 insertions, 30% (97,824 insertions) of which were performed in women with a delivery in the previous 12 months. For insertions performed in women who had delivered ≤ 52 weeks before IUD insertion, the majority of postpartum insertions, 57.3% (56,047 insertions) occurred between 6 and 14 weeks postpartum. Breastfeeding data were available in 94,817 insertions performed in women 52 weeks or less after delivery.

The study results indicated that the risk of uterine perforation was highest in women with IUD insertion ≤ 6 weeks postpartum. Immediate postpartum insertion (0–3 days) findings are limited due to the relatively small number of insertions occurring within this time interval. Women who were breastfeeding at the time of insertion were at 33% higher risk of perforation (adjusted hazard ratio [HR]=1.33, 95% confidence interval [CI]: 1.07–1.64) compared to women who were not breastfeeding at the time of insertion. Progressively lower risk of uterine perforation was observed in postpartum time windows beyond 6 weeks, in both breastfeeding and not breastfeeding women. Table 3 presents the uterine perforation rates for LNG IUS stratified by breastfeeding status and postpartum interval.

Table 3: Uterine Perforation¹ rates for LNG IUS, by Breastfeeding Status and Postpartum Interval

Risk of expulsion was variable over the postpartum intervals through 52 weeks. Women who were breastfeeding were at 28% lower risk of IUD expulsion (adjusted HR=0.72, 95% CI: 0.64-0.80) compared to women who were not breastfeeding at time of insertion. Table 4 presents the IUD expulsion rates for LNG IUS stratified by breastfeeding status and postpartum interval.

Table 4: Expulsion¹ Rates for LNG IUS, by Breastfeeding Status and Postpartum Interval

DRUG INTERACTIONS

No drug-drug interaction studies have been conducted with Mirena.

Drugs or herbal products that induce or inhibit LNG metabolizing enzymes, including CYP3A4, may decrease or increase, respectively, the serum concentrations of LNG during the use of Mirena. However, the contraceptive effect of Mirena is mediated via the direct release of LNG into the uterine cavity and is unlikely to be affected by drug interactions via enzyme induction or inhibition.

Read the entire FDA prescribing information for Mirena (Levonorgestrel-Releasing Intrauterine System)