November 25, 2015
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"Oct. 18, 2012 -- While the use of long-acting intrauterine devices (IUDs) is increasing, 1 in 9 women at risk for unintended pregnancies is not using any birth control, according to a new government report.

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Side Effects


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

Clinical Trials Experience

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

The data provided 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, 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 1.

Table 1 : Adverse Reactions ≥ 5% Reported in Clinical Trials with Mirena

System Organ Class Adverse Reactions % (N= 5,091)
Reproductive system and breast disorders alteration of menstrual bleeding pattern, including:  
unscheduled uterine bleeding 31.9
decreased uterine bleeding 23.4
increased scheduled uterine bleeding 11.9
female genital tract bleeding 3.5
amenorrhea 18.4
genital discharge 14.9
vulvovaginitis 10.5
breast pain 8.5
benign ovarian cyst and associated complications 7.5
dysmenorrhea 6.4
Gastrointestinal disorders abdominal/pelvic pain 22.6
Nervous system disorders headache/migraine 16.3
Musculoskeletal and connective tissue disorders back pain 7.9
Skin and subcutaneous tissue disorders acne 6.8
Psychiatric disorders depression/depressive mood 6.4

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

Postmarketing Experience

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 emboli, deep vein thrombosis and stroke
  • Device breakage
  • Hypersensitivity (including rash, urticaria and angioedema)
  • Increased blood pressure

Read the Mirena (levonorgestrel-releasing intrauterine system) Side Effects Center for a complete guide to possible side effects


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

Drugs or herbal products that induce enzymes, including CYP3A4, that metabolize progestins may decrease the serum concentrations of progestins.

Some drugs or herbal products that may decrease the serum concentration of LNG include:

  • Barbiturates
  • Bosentan
  • Carbamazepine
  • Efavirenz
  • Felbamate
  • Griseofulvin
  • Nevirapine
  • Oxcarbazepine
  • Phenytoin
  • Rifabutin
  • Rifampin
  • St. John's wort
  • Topiramate

Significant changes (increase or decrease) in the serum concentrations of the progestin have been noted in some cases of co-administration with HIV protease inhibitors or with non-nucleoside reverse transcriptase inhibitors. CYP3A4 inhibitors such as itraconazole or ketoconazole may increase plasma hormone levels.

Consult the labeling of all concurrently used drugs to obtain further information about interactions with Mirena or the potential for enzyme alterations.

This monograph has been modified to include the generic and brand name in many instances.

Last reviewed on RxList: 11/6/2015

Side Effects

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You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

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