Some commonly used brand names are:

In the U.S.—

In Canada—

Another commonly used name is norethisterone.

• Antianorectic --Megestrol
• Anticachetic --Megestrol
• Antineoplastic --Medroxyprogesterone ; Megestrol
• Diagnostic aid, estrogen production --Hydroxyprogesterone ; Medroxyprogesterone; Progesterone (parenteral)
• Infertility therapy adjunct --Progesterone (vaginal)
• Ovarian hormone therapy agent adjunct --Medroxyprogesterone (oral); Progesterone (oral)
• Progestational agent --Hydroxyprogesterone; Medrogestone; Medroxyprogesterone; Norethindrone; Progesterone

Progestins (proe-JES-tins ) are hormones. They are used by both men and women for different purposes.

Progestins are prescribed for several reasons:

• To properly regulate the menstrual cycle and treat unusual stopping of the menstrual periods (amenorrhea). Progestins work by causing changes in the uterus. After the amount of progestins in the blood drops, the lining of the uterus begins to come off and vaginal bleeding occurs (menstrual period). Progestins help other hormones start and stop the menstrual cycle.
• To help a pregnancy occur during egg donor or infertility procedures in women who do not produce enough progesterone. Also, progesterone is given to help maintain a pregnancy when not enough of it is made by the body.
• To prevent estrogen from thickening the lining of the uterus (endometrial hyperplasia) in women around menopause who are being treated with estrogen for ovarian hormone therapy (OHT). OHT is also called hormone replacement therapy (HRT) and estrogen replacement therapy (ERT).
• To treat a condition called endometriosis or unusual and heavy bleeding of the uterus (dysfunctional uterine bleeding) by starting or stopping the menstrual cycle.
• To help treat cancer of the breast, kidney, or uterus. Progestins help change the cancer cell's ability to react to other hormones and proteins that cause tumor growth. In this way, progestins can stop the growth of a tumor.
• To test the body's production of certain hormones such as estrogen.
• To treat loss of appetite and severe weight or muscle loss in patients with acquired immunodeficiency syndrome (AIDS) or cancer by causing certain proteins to be produced that cause increased appetite and weight gain.

Progestins may also be used for other conditions as determined by your doctor.

Depending on how much and which progestin you use or take, a progestin can have different effects. For instance, high doses of progesterone are necessary for some women to continue a pregnancy while other progestins in low doses can prevent a pregnancy from occurring. Other effects include causing weight gain, increasing body temperature, developing the milk-producing glands for breast-feeding, and relaxing the uterus to maintain a pregnancy.

Progestins can help other hormones work properly. Progestins may help to prevent anemia (low iron in blood), too much menstrual blood loss, and cancer of the uterus.

Progestins are available only with your doctor's prescription, in the following dosage forms:

Oral
• Medrogestone
  • Tablets (Canada)
• Medroxyprogesterone
  • Tablets (U.S. and Canada)
• Megestrol
  • Oral suspension (U.S. and Canada)
  • Tablets (U.S. and Canada)
• Norethindrone
  • Tablets (U.S. and Canada)
• Progesterone
  • Capsules (U.S. and Canada)

Parenteral
• Hydroxyprogesterone
  • Injection (U.S.)
• Medroxyprogesterone
  • Injection (U.S. and Canada)
• Progesterone
  • Injection (U.S. and Canada)

Vaginal
• Progesterone
  • Gel (U.S.)
  • Suppositories

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your health care professional will make. For progestins, the following should be considered:

Allergies—Tell your doctor if you have ever had any unusual reaction to progestins. If using progesterone capsules or injection, tell your doctor if you are allergic to peanuts. Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Diet—Make certain your health care professional knows if you are on any special diet, such as a low-sodium or low-sugar diet.

Pregnancy—Progesterone, a natural hormone that the body makes during pregnancy, has not caused problems. In fact, it is sometimes used in women to treat a certain type of infertility and to aid in egg donor or infertility procedures.

Other progestins have not been studied in pregnant women. Be sure to tell your doctor if you become pregnant while using any of the progestins. It is best to use some kind of birth control method while you are receiving progestins in high doses. High doses of progestins are not recommended for use during pregnancy since there have been some reports that they may cause birth defects in the genitals (sex organs) of a male fetus. Also, some of these progestins may cause male-like changes in a female fetus and female-like changes in a male fetus, but these problems usually can be reversed. Low doses of progestins, such as those doses used for contraception, have not caused major problems when used accidentally during pregnancy.

Breast-feeding—Although progestins pass into the breast milk, they have not been shown to cause problems in nursing babies. However, progestins may change the quality or amount (increase or decrease) of the mother's breast milk. It may be necessary for you to take another medicine or to stop breast-feeding during treatment. Be sure you have discussed the risks and benefits of the medicine with your doctor.

Children—Although there is no specific information comparing use of progestins in children with use in other age groups, this medicine is not expected to cause different side effects or problems in children than it does in adults.

Older adults—This medicine has been tested and has not been shown to cause different side effects or problems in older people than it does in younger adults.

Other medicines—Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking a progestin, it is especially important that your health care professional know if you are taking any of the following:

• Aminoglutethimide (e.g., Cytadren) or
• Carbamazepine (e.g., Tegretol) or
• Phenobarbital or
• Phenytoin (e.g., Dilantin) or
• Rifabutin (e.g., Mycobutin) or
• Rifampin (e.g., Rifadin, Rimactane)—These medicines may decrease the effects of progestins

• Asthma or
• Epilepsy (or history of) or
• Heart or circulation problems or
• Kidney disease (severe) or
• Migraine headaches—Progestins may cause fluid build-up and may cause these conditions to become worse

• Bleeding problems, undiagnosed, such as blood in urine or changes in vaginal bleeding—May make diagnosis of these problems more difficult

• Blood clots (or history of) or
• Stroke (or history of) or
• Varicose veins—May have greater chance of causing blood clots if these conditions are already present when high doses of progestins are taken

• Breast disease (such as breast lumps or cysts) (history of)—May make this condition worse in certain types of diseases that do not react in a positive way to progestins

• Central nervous system (CNS) disorders, such as mental depression (or history of) or
• High blood cholesterol—Effects of progestins may cause these conditions, or may make these conditions worse

• Diabetes mellitus (sugar diabetes)—May cause an increase in your blood sugar and a change in the amount of medicine you take for diabetes; progestins in high doses are more likely to cause this problem

• Liver disease—Effects of progestins may be increased and may make this condition worse

• Other conditions that increase the chances for osteoporosis (brittle bones)—Since it is possible that certain doses of progestins may cause temporary thinning of the bones by changing your hormone balance, it is important that your doctor know if you have an increased risk of osteoporosis. Some things that can increase your risk for having osteoporosis include cigarette smoking, abusing alcohol, taking or drinking large amounts of caffeine, and having a family history of osteoporosis or easily broken bones. Some medicines, such as glucocorticoids (cortisone-like medicines) or anticonvulsants (seizure medicine), can also cause thinning of the bones. However, it is thought that progestins can help protect against osteoporosis in postmenopausal women

To make the use of a progestin as safe and reliable as possible, you should understand how and when to take it and what effects may be expected. Progestins usually come with patient directions. Read them carefully before taking or using this medicine.

Take this medicine only as directed by your doctor. Do not take more of it and do not take it for a longer time than your doctor ordered. To do so may increase the chance of side effects. Try to take the medicine at the same time each day to reduce the possibility of side effects and to allow it to work better.

Progestins are often given together with certain medicines. If you are using a combination of medicines, make sure that you take each one at the proper time and do not mix them. Ask your health care professional to help you plan a way to remember to take your medicines at the right times.

Dosing—

The dose of these medicines will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of these medicines. If your dose is different, do not change it unless your doctor tells you to do so.

The number of tablets, injections, or suppositories that you take, receive, or use depends on the strength of the medicine. Also, the number of doses you take or use each day, the time allowed between doses, and the length of time you take or use the medicine depend on the medical problem for which you are taking progestins.

For hydroxyprogesterone
• For injection dosage form:
  • For controlling unusual and heavy bleeding of the uterus (dysfunctional uterine bleeding) or treating unusual stopping of menstrual periods (amenorrhea):
    • Adults and teenagers—375 milligrams (mg) injected into a muscle as a single dose.
  • For preparing the uterus for the menstrual period:
    • Adults and teenagers—125 to 250 mg injected into a muscle as a single dose on Day 10 of the menstrual cycle (counting from the first day of the last menstrual cycle). May be repeated every seven days if needed.

For medrogestone
• For oral dosage form (tablets):
  • For preparing the uterus for the menstrual period, controlling unusual and heavy bleeding of the uterus (dysfunctional uterine bleeding), preventing estrogen from thickening the lining of the uterus (endometrial hyperplasia) when taking estrogen for ovarian hormone therapy in postmenopausal women, or treating unusual stopping of menstrual periods (amenorrhea):
    • Adults and teenagers—5 to 10 milligrams (mg) a day for ten to fourteen days each month as directed by your doctor.

For medroxyprogesterone
• For oral dosage form (tablets):
  • For controlling unusual and heavy bleeding of the uterus (dysfunctional uterine bleeding) or treating unusual stopping of menstrual periods (amenorrhea):
    • Adults and teenagers—5 to 10 milligrams (mg) a day for five to ten days as directed by your doctor.
  • For preparing the uterus for the menstrual period:
    • Adults and teenagers—10 mg daily for five or ten days as directed by your doctor.
  • For preventing estrogen from thickening the lining of the uterus (endometrial hyperplasia) when taking estrogen for ovarian hormone therapy in postmenopausal women:
    • Adults—When taking estrogen each day on Days 1 through 25: Oral, 5 to 10 mg of medroxyprogesterone daily for ten to fourteen or more days each month as directed by your doctor. Or, your doctor may want you to take 2.5 or 5 mg a day without stopping. Your doctor will help decide the number of tablets that is best for you and when to take them.
• For injection dosage form:
  • For treating cancer of the kidneys or uterus:
    • Adults and teenagers—At first, 400 to 1000 milligrams (mg) injected into a muscle as a single dose once a week. Then, your doctor may lower your dose to 400 mg or more once a month.

For megestrol
• For oral dosage form (suspension):
  • For treating loss of appetite (anorexia), muscles (cachexia), or weight caused by acquired immunodeficiency syndrome (AIDS):
    • Adults and teenagers—800 milligrams (mg) a day for the first month. Then your doctor may want you to take 400 or 800 mg a day for three more months.
• For oral dosage form (tablets):
  • For treating cancer of the breast:
    • Adults and teenagers—160 mg a day as a single dose or in divided doses for two or more months.
  • For treating cancer of the uterus:
    • Adults and teenagers—40 to 320 mg a day for two or more months.
  • For treating loss of appetite (anorexia), muscles (cachexia), or weight caused by cancer:
    • Adults and teenagers—400 to 800 milligrams (mg) a day.

For norethindrone
• For oral dosage form (tablets):
  • For controlling unusual and heavy bleeding of the uterus (dysfunctional uterine bleeding) or treating unusual stopping of menstrual periods (amenorrhea):
    • Adults and teenagers—2.5 to 10 milligrams (mg) a day from Day 5 through Day 25 (counting from the first day of the last menstrual cycle). Or, your doctor may want you to take the medicine only for five to ten days as directed.
  • For treating endometriosis:
    • Adults and teenagers—At first, 5 mg a day for two weeks. Then, your doctor may increase your dose slowly up to 15 mg a day for six to nine months. Let your doctor know if your menstrual period starts. Your doctor may want you to take more of the medicine or may want you to stop taking the medicine for a short period of time.

For progesterone
• For oral dosage form (capsules):
  • For preventing estrogen from thickening the lining of the uterus (endometrial hyperplasia) when taking estrogen for ovarian hormone therapy in postmenopausal women:
    • Adults—200 mg a day at bedtime during the last fourteen days of estrogen treatment each month. Although other schedules are possible, usually treatment begins either on Day 8 through Day 21 of a twenty-eight–day cycle or on Day 12 through Day 25 of a thirty-day cycle. Your doctor may ask you not to take progestins or estrogens for the last five to seven days of each month. Sometimes your doctor may increase your dose to 100 mg in the morning to be taken 2 hours after breakfast and 200 mg to be taken at bedtime.
  • For treating unusual stopping of menstrual periods (amenorrhea):
    • Adults—400 mg a day in the evening for ten days.
• For vaginal dosage form (gel):
  • For treating unusual stopping of menstrual periods (amenorrhea):
    • Adults and teenagers—45 mg (one applicatorful of 4% gel) once every other day for up to six doses. Dose may be increased to 90 mg (one applicatorful of 8% gel) once every other day for up to six doses if needed.
  • For use with infertility procedures:
    • Adults and teenagers—90 mg (one applicatorful of 8% gel) one or two times a day. If pregnancy occurs, treatment can continue for up to ten to twelve weeks.
• For injection dosage form:
  • For controlling unusual and heavy bleeding of the uterus (dysfunctional uterine bleeding) or treating unusual stopping of menstrual periods (amenorrhea):
    • Adults and teenagers—5 to 10 milligrams (mg) a day injected into a muscle for six to ten days. Or, your doctor may want you to receive 100 or 150 mg injected into a muscle as a single dose. Sometimes your doctor may want you first to take another hormone called estrogen. If your menstrual period starts, your doctor will want you to stop taking the medicine.
• For suppositories dosage form (vaginal):
  • For maintaining a pregnancy (at ovulation and at the beginning of pregnancy):
    • Adults and teenagers—25 mg to 100 mg (one suppository) inserted into the vagina one or two times a day beginning near the time of ovulation. Your doctor may want you to receive the medicine for up to eleven weeks.

Missed dose—

For all progestins, except for progesterone capsules for postmenopausal women: If you miss a dose of this medicine, take the missed dose as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

For progesterone capsules for postmenopausal women: If you miss a dose of 200 mg of progesterone capsules at bedtime, take 100 mg in the morning then go back to your regular dosing schedule. If you take 300 mg of progesterone a day and you miss your morning and evening doses, you should not take the missed dose. Return to your regular dosing schedule.

Storage—

To store this medicine:

• Keep out of the reach of children.
• Store away from heat.
• Do not store in the bathroom, near the kitchen sink, or in any other damp places. Heat or moisture may cause the medicine to break down.
• Keep the injectable form of this medicine from freezing.
• Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.

It is very important that your doctor check your progress at regular visits. This will allow your dosage to be adjusted to your changing needs, and will allow any unwanted effects to be detected. These visits will usually be every 6 to 12 months, but some doctors require them more often.

Progestins may cause some people to become dizzy. For oral or vaginal progesterone, dizziness or drowsiness may occur 1 to 4 hours after taking or using it. Make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are not alert.

Unusual or unexpected vaginal bleeding of various amounts may occur between your regular menstrual periods during the first 3 months of use. This is sometimes called spotting when slight, or breakthrough menstrual bleeding when heavier. If this should occur, continue on your regular dosing schedule. Check with your doctor:

• If unusual or unexpected vaginal bleeding continues for an unusually long time.
• If your menstrual period has not started within 45 days of your last period.

Missed menstrual periods may occur. If you suspect a pregnancy, you should stop taking this medicine immediately and call your doctor. Your doctor will let you know if you should continue taking the progestin.

If you are scheduled for any laboratory tests, tell your health care professional that you are taking a progestin. Progestins can change certain test results.

In some patients, tenderness, swelling, or bleeding of the gums may occur. Brushing and flossing your teeth carefully and regularly and massaging your gums may help prevent this. See your dentist regularly to have your teeth cleaned. Check with your medical doctor or dentist if you have any questions about how to take care of your teeth and gums, or if you notice any tenderness, swelling, or bleeding of your gums.

You will need to use a birth control method while taking progestins for noncontraceptive use if you are fertile and sexually active .

If you are using vaginal progesterone, avoid using other vaginal products for 6 hours before and for 6 hours after inserting the vaginal dose of progesterone.

Along with their needed effects, progestins used in high doses sometimes cause some unwanted effects such as blood clots, heart attacks, and strokes, or problems of the liver and eyes. Although these effects are rare, some of them can be very serious and cause death. It is not clear if these problems are due to the progestin. They may be caused by the disease or condition for which progestins are being used.

The following side effects may be caused by blood clots. Although not all of these side effects may occur, if they do occur they need immediate medical attention. Get emergency help immediately if any of the following side effects occur:

• Rare
  • Symptoms of blood clotting problems, usually severe or sudden, such as headache or migraine;  loss of or change in speech, coordination, or vision;  numbness of or pain in chest, arm, or leg;  unexplained shortness of breath 
  
  

Also, check with your doctor as soon as possible if any of the following side effects occur:

• More common
  • Changes in vaginal bleeding (increased amounts of menstrual bleeding occurring at regular monthly periods, lighter vaginal bleeding between menstrual periods, heavier vaginal bleeding between regular monthly periods, or stopping of menstrual periods);  symptoms of blood sugar problems (dry mouth, frequent urination, loss of appetite, or unusual thirst) 
  
  

• Less common
  • Mental depression;  skin rash;  unexpected or increased flow of breast milk 
  
  

• Rare
  • For megestrol—During chronic treatment
    • Backache;  dizziness;  filling or rounding out of the face;  irritability ;  mental depression;  unusual decrease in sexual desire or ability in men;  nausea or vomiting;  unusual tiredness or weakness  
    
    

Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor if any of the following side effects continue or are bothersome:

• More common
  • Abdominal pain or cramping;  bloating or swelling of ankles or feet;  blood pressure increase (mild);  dizziness;  drowsiness (progesterone only);  headache (mild);  mood changes;  nervousness;  pain or irritation at place of injection site;  swelling of face, ankles, or feet;  unusual or rapid weight gain 
  
  

• Less common
  • Acne;  breast pain or tenderness;  brown spots on exposed skin, possibly long-lasting;  hot flashes;  loss or gain of body, facial, or scalp hair;  loss of sexual desire;  trouble in sleeping 
  
  

Not all of the side effects listed above have been reported for each of these medicines, but they have been reported for at least one of them. All of the progestins are similar, so any of the above side effects may occur with any of these medicines.

After you stop using this medicine, your body may need time to adjust. The length of time this takes depends on the amount of medicine you were using and how long you used it. During this period of time check with your doctor if you notice the following side effect:

• Delayed return to fertility;  stopping of menstrual periods;  unusual menstrual bleeding (continuing) 

• For megestrol
  • Dizziness;  nausea or vomiting;  unusual tiredness or weakness 
  
  

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.

Once a medicine has been approved for marketing for a certain use, experience may show that it is also useful for other medical problems. Although these uses are not included in product labeling, progestins are used in certain patients with the following medical conditions:

• Carcinoma of the prostate
• Corpus luteum insufficiency
• Endometrial hyperplasia
• Hot flashes
• Polycystic ovary syndrome
• Precocious puberty

Other than the above information, there is no additional information relating to proper use, precautions, or side effects for these uses.