Hormonal therapy stops the production or blocks the action of male hormones, and causes castration. Your body can react to castration in different ways. The most common side effects of castration are:
Lower sex drive
Increased risk of heart disease
You could also experience pain, for example in your joints, your back, your bones, or muscles.
Changing hormone levels can affect your blood and cause high blood pressure, dizziness, and bruising. You may also be at higher risk of infection, especially in the nose or throat, or urinary tract infections.
Loss of appetite and weight loss can also be a result of castration. These may be related to diarrhoea, constipation, or vomiting caused by the hormone changes.
Other side effects may include coughing, shortness of breath, headaches, and peripheral oedema.
The different treatments may cause side effects as well.
LHRH antagonists may cause an allergic reaction.
Anti-androgens may cause swelling of your breasts. This is called gynaecomastia and can be painful in some cases. To prevent gynaecomastia your doctor may recommend radiation therapy of your chest before the start of the hormonal therapy. In rare cases, you may need surgery to remove the mammary glands.
Anti-androgens could worsen hot flushes. These can be treated with low-dose oestrogens. Oestrogens can increase the risk of heart disease. Flutamide can cause diarrhoea.
How bothersome the side effects of hormonal therapy are, and when they appear, varies from person to person. This is related to your general health and the type of treatment you get.