Side effects of hormone therapy

The side effects of hormone therapy will depend mainly on the type of hormone therapy you received, the dose you were given, how you received it, and your overall health. Side effects can happen with any type of treatment, though not everyone has them or experiences them in the same way.

If you develop side effects, they can happen at any time: during, immediately after, or days or even weeks following hormone therapy. Tell your healthcare team right away if you have side effects that you think might be from hormone therapy. The sooner you tell them, the sooner they can treat you for any problems, or suggest ways that you can manage them.

The following are the most common side effects of hormone therapy.

Fatigue is a feeling of tiredness, exhaustion or a general lack of energy. It’s different from the tiredness a person usually feels at the end of the day and it can be a serious problem.

Fatigue tends to be worse when you are having other treatments, such as chemotherapy or radiation therapy. Fatigue may get better throughout treatment, but it can sometimes last for a long time.

Find out more about fatigue.

A hot flash is the sudden feeling of warmth. Hot flashes can cause sweating, flushing and redness on the skin. Some hormone drug therapies can cause hot flashes in anyone receiving the therapy. This side effect usually gets better as your body gets used to the treatment or when you stop receiving the hormone drug therapy.

Talk to your healthcare team about ways to manage hot flashes. Check with them before taking herbal products to treat hot flashes because some may have ingredients that can affect a hormone-related cancer.

Some hormone drug therapies can cause people to gain weight. This can be due to having low levels of hormones in the body or because the treatment increases your appetite. Controlling weight can be difficult when you are having hormone therapy but changing your diet and increasing exercise may help. A dietitian can help you find ways to manage weight gain during treatment.

Find out more about weight gain.

Osteoporosis is when bones lose density and the bone tissue breaks down. Hormone therapies that lower estrogen and testosterone can lead to osteoporosis. Hormone therapies that cause early menopause can also cause osteoporosis because there is less estrogen in the body.

You may have a bone mineral density test before starting hormone drug therapy. This test gives you and your doctor a baseline for comparison with follow-up tests.

Find out more about osteoporosis.

Hormone therapy can cause pain including aches or pain in the muscles, joints and headaches.

Find out more about pain.

Some hormone drug therapies can cause breast swelling or tenderness.

Hormone therapy can cause sexual problems or make sex difficult. Some hormone therapies can cause a low sex drive (less or loss of interest in sex), vaginal dryness or inability to achieve or maintain an erection (erectile dysfunction).

Find out more about sexual problems in male sex organs and female sex organs.

Menopause occurs when the ovaries stop making estrogen and you have not had a menstrual period for at least 12 months. Menopause usually happens when someone is around 50 years of age. Some cancer treatments cause menopause to occur earlier. This is called treatment-induced menopause.

Treatment-induced menopause can be permanent in women who’ve had their ovaries surgically removed. Treatment-induced menopause in women who’ve had hormone drug therapy may be temporary. But for some women, it can be permanent, especially if they are near natural menopause when they start hormone drug therapy.

The symptoms of treatment-induced menopause are the same as the symptoms of natural menopause, but they may be more severe because treatment-induced menopause happens quickly.

Find out more about treatment-induced menopause.

Hormone therapy may cause fertility problems, depending on the type of therapy you receive. Fertility is your ability to get or stay pregnant or get someone pregnant and have a child. If your testicles or ovaries are surgically removed, you may have a permanent loss of fertility (infertility). Hormone drug therapy can also cause a temporary loss of fertility.

Find out more about fertility problems.

Hormone drug therapies such as luteinizing hormone–releasing hormone (LHRH) agonists may cause symptoms, such as pain, to worsen temporarily. This is called a tumour flare reaction. This side effect usually goes away after a few weeks. To prevent a tumour flare, your doctor may give you another hormone therapy drug called an anti-androgen.

A blood clot may develop in your leg or lung during hormone therapy. Blood clots can be serious. Signs and symptoms include pain, redness or swelling in your leg, trouble breathing and chest pain. This cancer-related emergency needs to be treated right away.

Nausea is feeling sick to your stomach, and vomiting is throwing up. These sometimes occur together. Some hormone drug therapies can cause nausea and vomiting. These side effects usually get better as your body gets used to the drug. Taking hormone therapy drugs with food or at bedtime may help relieve these side effects.

Find out more about nausea and vomiting.

Diarrhea is the frequent passing of loose, watery stools. Some hormone drug therapies affect the cells that line the gastrointestinal (GI) tract. When hormone drug therapies affect those cells they can cause diarrhea.

Find out more about diarrhea.