Side Effects Common to All Hormonal Therapies

All hormonal therapies lower the effects of estrogen in many areas of your body, just like going through natural menopause. These treatments produce menopause-like side effects in up to half of the women who take them, including:

• early start of menopause (may be reversed after you stop taking hormonal therapy)
• hot flashes
• weight gain or bloating
• vaginal dryness
• mood swings
• depression

Each woman experiences hormonal therapy differently. And over time, the number and nature of symptoms can vary. Symptoms depend largely on whether you are pre- or post-menopausal before starting hormonal therapy and on how fast your body's estrogen levels drop. Read more about how menopausal symptoms might affect you.

Pre-menopausal women who go through ovarian shutdown or removal have a rapid drop in estrogen levels. They often experience intense menopausal symptoms. This is especially true if they have gone into menopause early because of chemotherapy and then begin hormonal therapy, which drops estrogen levels even further.

If you have already gone through menopause, you have less estrogen in your body to begin with. Taking an aromatase inhibitor drops estrogen levels even further, so you may experience increased menopausal symptoms on Arimidex (chemical name: anastrozole), Aromasin (chemical name: exemestane), or Femara (chemical name: letrozole).

Tamoxifen acts as a weak estrogen in places other than breast tissue throughout the body, including the brain. Brain hormones are responsible for keeping the body's thermostat running smoothly. When the brain hormones can't trigger more estrogen production (because tamoxifen is sitting in the estrogen receptor), the thermostat can't regulate itself, and reacts by turning up the heat. Tamoxifen tends to produce worse hot flashes than aromatase inhibitors. Find out about tamoxifen and HRT.

Read on to find out more about the side effects common to all hormonal therapies.

Premature (early start of) menopause

Some pre-menopausal women find that their menstrual periods stop while they are taking hormonal medications. This might mean going into either a temporary menopause or an early start of menopause, which is permanent and cannot be reversed.

If you were having regular periods before you started taking hormonal therapy, but your menstrual cycle has since become irregular or stopped, your cycle will probably return to normal when you stop taking the medicine.

Most women who go through natural menopause are around 51 or 52 when it occurs. So, if you are close to natural menopause when you begin taking hormonal therapy, you may reach permanent menopause a little sooner than you would have otherwise.

Keep in mind also that hormonal therapy is given over five years and sometimes longer. During those years, the regular aging process that we all go through is also working on your ovaries. Hormone levels drop as the brain's hormones that "turn on" estrogen in the ovaries give fewer and fewer messages over time. This natural drop in estrogen levels is separate from the effects of hormonal therapy.

Menopause happens to every woman sooner or later. Learn more about menopause and breast cancer and about what this stage of life might be like for you. 

Hot flashes

About half of the women who take hormonal therapies experience hot flashes. Some women call them "hot flushes," "heat waves," or "power surges." When estrogen levels drop or the estrogen receptors are blocked, your body's temperature control system gets confused. The result: hot flashes. Hot flashes can be mild and manageable. They can also make you miserable. But hot flashes themselves are not dangerous or life-threatening.

Most women find hot flashes to be the most uncomfortable side effect of hormonal therapy. Some women adjust, and others figure out how to deal with the problem. Hot flashes tend to ease up over time. Women with severe hot flashes will need to learn to manage them while taking hormonal therapy.

You can take medications to treat hot flashes, including low doses of certain antidepressants and other medicines that reduce hot flash triggers inside the brain. Effexor (chemical name: venlafaxine) and Paxil (chemical name: paroxetine) are two examples. One small study found that Neurontin (chemical name: gabapentin), a drug used to treat seizures significantly reduced the number and severity of hot flashes for women taking tamoxifen.

Be sure to talk to your doctor about these medical options if hot flashes continue to be a problem. You deserve relief.

If you are taking either tamoxifen or aromatase inhibitors and having hot flashes, you might ask your doctor if it would be possible to stop your hormonal treatment for a week or two, and then restart with a lower dose, and slowly increase the dose back up to the dose you were originally taking. Your body may adjust better with this slowly increasing dosage.

Changes in the vagina

You may notice vaginal itching and a bad-smelling discharge while on hormonal therapies. That's because the lack of estrogen can cause a change in the "environment" of the vagina that makes it more inviting to yeast. This creates an ongoing yeast infection of the vagina and vulva (including all of the areas tucked inside, such as under the hood of the clitoris). The infection produces a white paste or small cottage-cheese-like curds in the vaginal area.

To lower your risk of developing yeast infections, gently rinse out your vagina and vulva on a regular basis with water. Ask your doctor if it's okay use a little bit of a VERY mild soap (like Dove).

If you have obvious signs of yeast infection or your doctor diagnoses yeast, then you can use a medication that helps get the yeast under control. Some of these anti-yeast creams can be bought over the counter.

Vaginal dryness is another side effect of a low-estrogen environment in this part of the body. You can get a build-up of dried vaginal secretions that is also thick and white. This can look like a yeast infection, but it really isn't. Sometimes, intercourse may become painful, which can decrease your sexual activity or bring it to a halt. Water-based lubricants, which you can buy over the counter in the drugstore, can help to take care of this problem. Discuss any vaginal changes with your doctor.

Nausea and vomiting

A problem for about 10% of women on hormonal therapies, nausea and vomiting is usually mild and stops in a few weeks. It's uncommon for it to last more than a few months. Feeling sick to your stomach can be an unpleasant experience, even if it poses no danger. Ask your doctor about anti-nausea medications to ease these symptoms. Read more information on how to deal with nausea and vomiting.

Weight gain

Many women gain weight during chemotherapy, and from the steroids that are sometimes given with it. That weight gain may continue after chemotherapy, while you are on hormonal therapies. Many women report increased weight gain when taking hormonal therapies, although the exact cause of the weight gain is unclear.

Many women feel certain that hormonal therapy is to blame. They often say they are sure tamoxifen or aromatase inhibitors have made them gain weight and keep it on. But two of the major studies conducted in the United States and Canada by the National Surgical Adjuvant Breast and Bowel Project (NSABP, a cooperative research group) showed that women taking a placebo (a sugar pill) were just as likely to gain weight as women taking tamoxifen.

There are many possible reasons for this weight gain:

• You may have gained weight during the chemotherapy before taking hormonal therapies.
• You may be less physically active but eating as much as (or more than) before. And you may need fewer calories to maintain the same weight because of menopausal changes in your overall metabolism.
• You may have stopped smoking and found yourself snacking more instead.
• You may be struggling with overeating because of a wounded self-image, anxiety, and depression.
• You are growing older. As we move through life, we have a tendency to gain weight.

If you haven't gained weight in the first six months of hormonal treatment, you're probably not going to have the problem. A few women actually LOSE weight on hormonal therapy, and some women who have gained weight do manage to lose it over time.

Mood swings and depression

You may feel moody or depressed when you take hormonal therapies, but it isn't clear that those feelings are caused by the hormonal therapy alone. Two of the major studies by the NSABP also found that depression was not more common in women taking tamoxifen than in women taking a placebo (sugar pill).

Whatever the cause, depression that doesn't go away shouldn't be ignored. It should be evaluated and treated by an experienced professional. Depending on how severe depression is, it can be treated with psychotherapy, medication, or both.

To get some relief, your doctor may suggest that you temporarily stop or reduce your dosage of hormonal therapy. This can ease depression somewhat but doesn't usually take the problem away completely. Medicines that work against depression, combined with counseling, can be quite helpful for more lasting relief.

Some women on hormonal therapies have reported anxiety attacks. If you experience anxiety attacks (unexplained fear, shortness of breath, tightness in the chest) that don't go away, get help. Medication and counseling can both make a big difference against anxiety.

This is a hard time in your life. Don't put up with unnecessary pain—either physical or psychological. Get help!

Loss of energy

You may feel a loss of energy with hormonal treatment, just as you might with natural menopause. In both situations, there is less estrogen, the "go-go juice" that some women depend on for energy. Actually, a whole list of things other than hormonal therapies can steal your energy. Lack of exercise, weight gain, pain, hot flashes, fear, uncertainty, anxiety, and depression are all energy-robbers. Try making a little private time during the day for yourself to do something you enjoy a lot that boosts your interest and therefore your energy.

Flare reaction in women with advanced (metastatic) cancer

In women with advanced cancer, all hormonal therapies can cause a "flare" reaction shortly after they are begun. This temporary increase of pain occurs as the tumor reacts to being starved of the estrogen it needs to grow. Although uncomfortable, the flare reaction is a sign that the treatment is working. (But not everyone gets flare pain. If you don't have pain, that doesn't mean the hormonal therapy ISN'T working.) Pain medicines can help relieve the discomfort of a flare reaction, which often goes away within a few months.