Medroxyprogesterone is a form of progesterone, a female hormone that prevents ovulation (the release of an egg from an ovary). medroxyprogesterone also causes changes in your cervical mucus and uterine lining, making it harder for sperm to reach the uterus and harder for a fertilized egg to attach to the uterus.

Medroxyprogesterone is used as contraception to prevent pregnancy. It is also used to reduce pain caused by endometriosis.

Medroxyprogesterone may also be used for purposes not listed in this medication guide.

You should not use medroxyprogesterone if you have: undiagnosed vaginal bleeding, liver disease, breast cancer, if you are pregnant, or if you have ever had a stroke or blood clot.

Medroxyprogesterone can decrease the calcium stored in your bones, which may cause bone loss (osteoporosis) when the medicine is used over long periods of time. Bone loss may not be reversible.

You may be more likely to have a broken bone if your bones get weak from calcium loss, especially after menopause. You should not use medroxyprogesterone for longer than 2 years unless other birth control methods are not right for you.

Medroxyprogesterone is injected into a muscle or under the skin. A healthcare provider will give you this injection once every 3 months (12 to 14 weeks).

You may have breakthrough bleeding while using medroxyprogesterone. Tell your doctor if this bleeding continues or is very heavy.

medroxyprogesterone can affect the results of certain medical tests. Tell any doctor who treats you that you are using medroxyprogesterone.

Your doctor will need to see you on a regular basis while you are using medroxyprogesterone. If you use this medicine long-term, your bone density may need to be checked during treatment.

You may need to have a negative pregnancy test before you start this medicine.

You should not use medroxyprogesterone if you are pregnant, or if you have:

• abnormal vaginal bleeding that has not been checked by a doctor;

• liver disease;

• breast cancer; or

• a history of stroke or blood clot.

Medroxyprogesterone can decrease the calcium stored in your bones, which may cause bone loss (osteoporosis) when the medicine is used over long periods of time. Bone loss may not be reversible.

You may be more likely to have a broken bone if your bones get weak from calcium loss, especially after menopause. You should not use this medicine for longer than 2 years unless other birth control methods are not right for you. Ask your doctor.

Tell your doctor if you have ever had:

• light or irregular menstrual periods;

• risk factors for osteoporosis (such as low bone mineral density, a family history of osteoporosis, drinking large amounts of alcohol, or if you smoke);

• a breast lump, an abnormal mammogram, or bleeding from your nipples;

• kidney disease;

• high blood pressure;

• breast cancer (in you or a family member);

• diabetes;

• depression, or an eating disorder;

• seizures;

• asthma; or

• migraine headaches.

Tell your doctor right away if you become pregnant, or if you plan to become pregnant soon after you stop using medroxyprogesterone.

It may not be safe to breastfeed while using this medicine. Ask your doctor about any risk.

Medroxyprogesterone will not be effective in preventing pregnancy if you do not receive an injection every 3 months.

If you plan to continue using this medicine, get the missed injection as soon as possible. Use a non-hormonal back-up birth control (such as a condom or diaphragm with spermicide) until you receive the missed injection.

You may need to have a negative pregnancy test before you receive a missed injection.

If more than 14 weeks have passed since your last injection, you may be able to get pregnant. The longer you wait between injections, the more likely you are to get pregnant.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

medroxyprogesterone will not protect you from sexually transmitted diseases--including HIV and AIDS. Using a condom is the only way to protect yourself from these diseases.

Get emergency medical help if you have signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Medroxyprogesterone may cause serious side effects. Call your doctor at once if you have:

• menstrual periods that are heavier or longer than normal;

• severe pain in your lower stomach;

• swelling in your face, or your hands, ankles, and feet;

• pain, bleeding, oozing (pus), or skin changes where the injection was given;

• symptoms of depression (sleep problems, weakness, mood changes);

• liver problems--upper stomach pain, itching, tiredness, dark urine, jaundice (yellowing of the skin or eyes); or

• signs of a blood clot--sudden numbness or weakness, severe headache, chest pain, sudden cough, coughing up blood; problems with vision or speech, swelling or pain in an arm or leg.

Common side effects of medroxyprogesterone may include:

• changes in your menstrual periods;

• weakness, feeling tired;

• stomach pain;

• feeling nervous;

• decreased sexual drive;

• weight gain;

• headache, dizziness; or

• lumps or dimpling in your skin where injections were given.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Sometimes it is not safe to use certain medications at the same time. Some drugs can lower your blood levels of medroxyprogesterone and make it less effective in preventing pregnancy.

Tell your doctor about all your other medicines, especially:

• St. John's wort;

• sleep medicine;

• seizure medicine;

• medicine to treat an infection;

• HIV or AIDS medication;

• bosentan;

• modafinil; or

• mitotane.

This list is not complete and many other drugs may affect medroxyprogesterone. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.