Medication Search: Mirena

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Common Name:

levonorgestrel IUD


How does this medication work? What will it do for me?

This is a soft, flexible, T-shaped contraceptive (birth control) device that is placed inside the uterus (intrauterine device or IUD). The medication is continuously released over a period of 8 years to prevent pregnancy.

It is also used to treat heavy menstrual bleeding. Levonorgestrel is a progestin, which is a hormone produced by the ovaries. This medication prevents the lining of the uterus (endometrium) from building up, which makes it very difficult for an egg to be implanted and also helps to manage heavy menstrual bleeding. It also changes the cervical mucus, making it harder for sperm to swim through the cervix.

Levonorgestrel IUD starts to work as soon as it is inserted. However, it is advised to wait 24 to 48 hours before having sexual intercourse.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are being given this medication, speak to your doctor.

Do not give this contraceptive device to anyone else. It can be harmful for people to use this contraceptive device if their doctor has not prescribed it. Do not try to remove this contraceptive device without consulting your doctor.

What form(s) does this medication come in?

Mirena®; is supplied as a soft, flexible, T-shaped device about the size of a quarter. It contains 52 mg of levonorgestrel in a cylindrical-shaped reservoir. The reservoir is mounted on a T-shaped frame and covered with a rate-controlling membrane of polydimethylsiloxane and silica. The T-frame is coloured with barium sulfate. The polyethylene removal threads attached to the T-frame are coloured with black iron oxide.

How should I use this medication?

This device is placed inside the uterus by your doctor within 7 days after the start of your period. Your doctor will most likely perform a gynecological examination before the device is inserted to examine your uterus for correct placement and to rule out pregnancy or other gynecological conditions that would make using levonorgestrel undesirable.

The device is inserted during a routine office visit with your doctor and only takes a few minutes. You may have to go back to your doctor’s office about 4 to 12 weeks after the device is inserted to ensure it is in the right position, and then once a year thereafter or as directed by your doctor. The device can be left in place for up to 8 years for pregnancy prevention, or 5 years for the treatment of menstrual problems. After this time, a decision must be made whether to replace the device with a new one or simply to remove the old device.

It is important to use this contraceptive device exactly as prescribed by your doctor.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are using the medication without consulting your doctor.

Do not dispose of medications in wastewater (e.g. down the sink or in the toilet) or in household garbage. Ask your pharmacist how to dispose of medications that are no longer needed or have expired.

Who should NOT take this medication?

Do not use the levonorgestrel IUD if you:

  • are allergic to levonorgestrel or to any of the ingredients or components of the device
  • are or may be pregnant
  • have a bacterial infection of the heart valves
  • have a condition that may increase the risk of pelvic infections
  • have a genital infection
  • have a poorly functioning immune system
  • have a previously inserted intrauterine device (IUD) that has not been removed
  • have a progestin-dependent cancer, including breast cancer
  • have abnormal cells in the cervix
  • have abnormalities of the uterus (e.g., fibroids) that distort the shape of the uterus
  • have acute liver disease or a liver tumour
  • have cancer of the uterus or cervix
  • have current or recurrent pelvic inflammatory disease
  • have had an abortion complicated by an infection within the past 3 months
  • have inflammation of the cervix
  • have inflammation of the endometrium (lining of the uterus) after pregnancy
  • have leukemia or other cancers affecting the blood
  • have recently had an abnormal growth of cells inside the uterus
  • have unexplained bleeding of the uterus

What side effects are possible with this medication?

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

  • abdominal pain
  • acne (usually less common after 3 months of treatment, and may improve if acne already exists)
  • breast pain, tenderness, or swelling
  • changes in hair growth
  • changes in the menstrual pattern, such as:
    • breakthrough bleeding or spotting between periods
    • complete lack of menstrual flow for several months in a row
    • decreased bleeding during periods
    • occasional stopping of menstrual bleeding
    • prolonged bleeding during periods
  • dark skin patches
  • decreased sex drive
  • feeling of fullness or tightness in the abdomen
  • hair loss
  • headache
  • oily skin
  • painful periods
  • nausea
  • weight gain

Although most of the side effects listed below don’t happen very often, they could lead to serious problems if you do not seek medical attention.
Check with your doctor as soon as possible if any of the following side effects occur:

  • back pain
  • dizziness
  • expulsion or breakage of the device
  • increased blood pressure
  • mood changes
  • nervousness
  • persistent or severe lower abdominal pain along with fever or unusual vaginal discharge
  • severe headaches or migraines (headaches may lessen in many users, or they may increase in number or become worse for other users)
  • signs of depression (e.g., poor concentration, changes in weight, changes in sleep, decreased interest in activities, thoughts of suicide)
  • signs of a liver problem (e.g., yellow skin or eyes, dark urine, pale stools, abdominal pain, or itchy skin)
  • skin rash, hives, or itchy skin
  • symptoms of pregnancy (e.g., abdominal pain, nausea, breast tenderness)
  • vaginal discharge
  • vaginal infection with vaginal itching or irritation, or thick, white, or curd-like discharge

Stop taking the medication and seek immediate medical attention if any of the following occur:

  • abdominal or stomach pain (sudden, severe, or continuing)
  • signs of a serious allergic reaction (e.g., abdominal cramps, difficulty breathing, nausea and vomiting, or swelling of the face and throat)
  • signs of a blood clot in the leg (e.g., sudden unexplained pain in the leg, especially in the calf)
  • signs of a blood clot in the lungs (e.g., sudden or unexplained shortness of breath, chest pain, coughing up of blood)
  • signs of a heart attack (e.g., pain or discomfort in the chest or upper body, shortness of breath, nausea, cold sweats, or lightheadedness)
  • signs of a stroke (e.g., sudden slurring of speech; sudden unexplained weakness, numbness, or pain in the arm or leg; sudden loss of coordination; sudden, severe headache)
  • symptoms of a blood infection (e.g., chills, confusion, delirium, fever, rapid heartbeat, warm skin)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Are there any other precautions or warnings for this medication?

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Blood pressure: Levonorgestrel can cause an increase in blood pressure. If you have high blood pressure, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

If you experience an increase in your blood pressure after having this device inserted, contact your doctor.

Breast cancer: Cases of breast cancer have been reported by people using levonorgestrel-releasing IUDs. However, some studies have shown that progestin-only forms of birth control do not appear to increase the risk of breast cancer. Discuss any concerns you have with your doctor.

Depression: Hormones, such as progestins, are known to contribute to mood swings and symptoms of depression. If you have depression or a history of depression, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

If you experience symptoms of depression such as poor concentration, changes in weight, changes in sleep, decreased interest in activities, or notice them in a family member who is taking this medication, contact your doctor as soon as possible.

Diabetes: Low-dose contraceptives such as this device have very little effect on blood sugar control. However, people with diabetes or those with a family history of diabetes should monitor their blood sugar closely to detect any worsening of blood sugar control.

Ectopic pregnancy: If you have a history of ectopic pregnancy (when a fertilized egg implants itself outside of the uterus), have had surgery on the fallopian tubes, or have had a pelvic infection, you should speak to your doctor or pharmacist before using this device. If you experience lower abdominal pain along with a missed period or unexpected bleeding while using this medication, contact your doctor.

Expulsion of device: Bleeding or pain may indicate that the device has either moved out of position or has been expelled from the uterine cavity. A device that is out of position is less effective and should be removed and replaced by a new device.

Eye problems: Some people may experience a change in vision or contact lens tolerance. If this occurs, contact your eye doctor.

Headache: Levonorgestrel, like other hormones, may cause severe headache or migraine. If you have a history of migraines, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

If you notice increasing numbers or severity of headaches after the device has been inserted, contact your doctor as soon as possible.

Heart disease: Levonorgestrel may increase the risk of developing blood clots, causing reduced blood flow to organs or the extremities. If you have a history of clotting you may be at increased risk of experiencing blood clot-related problems such as heart attack, stroke, or clots in the deep veins of your leg. Cigarette smoking increases the risk of serious adverse effects on the heart and blood vessels. Discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

If you experience symptoms such as sharp pain and swelling in the leg, difficulty breathing, chest pain, blurred vision, or difficulty speaking, contact your doctor immediately.

Heart valve disorders: This medication can increase your risk of getting an infection in your heart valves if you were born with or have acquired a heart valve defect. You may need to take antibiotics before the insertion and removal of this medication to prevent the infection.

Infection: Rarely, insertion of an IUD can lead to serious infection that can spread into the blood stream. If you experience long-lasting or heavy bleeding, unusual vaginal discharge, stomach pain, chills, or fever, contact you doctor as soon as possible. It is important to treat any infection in the uterus before it has an opportunity to spread.

Insertion and removal of the device: Some people may experience some pain and bleeding when the device is inserted or removed. The procedure may also cause fainting or a seizure for someone with a seizure disorder.

Liver disease: If you develop signs of a liver problem (yellow skin or eyes, dark urine, pale stools, abdominal pain, or itchy skin), talk to your doctor about whether you should have the device removed.

Menstrual bleeding: Some people may experience some pain and bleeding when the device is inserted or removed. Irregular menstrual bleeding is common for the first few months after the device is inserted. Over time, menstrual bleeding decreases and may stop completely while the device is inserted.

Ovarian cysts: This medication can cause the development of ovarian cysts. Most of these don’t have any symptoms and disappear on their own within 2 to 3 months. However, if you experience pain in the pelvic area, contact your doctor.

Pelvic infections: There is an increased risk of pelvic infections within the first 20 days after insertion of the device. This risk may be higher for those with risk factors (e.g., multiple sexual partners, frequent intercourse, young age). If you develop signs persistent lower abdominal pain, as well as a fever or unusual vaginal discharge, contact your doctor immediately. People who experience recurrent infections or experience infections that don’t clear within a few days with treatment may need to have the device removed.

Perforation: The chance of the device puncturing the cervix or uterus is very rare (between 1 in 1,000 and 1 in 10,000). If it were to occur, it would most likely be when the device is being inserted. If this happens, the device should be removed as soon as possible.

Removal of the device: If you experience any of the following, check with your doctor to see if you should have your device removed:

  • confirmed or suspected breast or endometrial cancer
  • migraines or severe headaches
  • recurrent inflammation of the lining of the uterus
  • recurrent pelvic infections
  • significantly elevated blood pressure
  • stroke or heart attack

Return to fertility: Your usual level of fertility should return soon after the device is removed. Nearly 90% of people wishing to become pregnant conceive within 24 months after removal of the device.

Sexually transmitted infections (STIs): This device does not protect against STIs, including HIV/AIDS. For protection against STIs, use latex condoms.

Pregnancy: This device should not be used during pregnancy. You should have this device removed if you become pregnant. Any device in the uterus during pregnancy can result in an increased risk of miscarriage or early labour. There is no evidence of birth defects when the device remains in the uterus for the full term. However, there is no conclusive evidence of this because of limited experience.

Breast-feeding: Hormonal birth control, such as this device, is not the first choice of birth control for those who are breast-feeding. This medication passes into breast milk. If you are breast-feeding and are using levonorgestrel, it may affect your baby. Some people using this medication have reported decreased milk production. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of using this medication have not been established for children under 18 years of age. This contraceptive device is not the first option of contraception for people that have not been pregnant before.

What other drugs could interact with this medication?

For a full list of interactions, use the Drug Interaction Checker available on the website.

If you are taking other medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

  • stop taking one of the medications,
  • change one of the medications to another,
  • change how you are taking one or both of the medications, or
  • leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.

All material copyright MediResource Inc. 1996 – 2024. Terms and conditions of use. The contents herein are for informational purposes only. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Source:

Last Updated: 16/07/2024