Mild burning/pain/bruising at the injection site, hot flashes (flushing), increased sweating, night sweats, tiredness, headache, upset stomach, breast changes, acne, joint/muscle aches, trouble sleeping, reduced sexual interest, vaginal discomfort/dryness, vaginal bleeding, swelling of the ankles/feet, increased urination at night, or dizziness may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly. Infrequently in men, shrinking of the testicles, breast tenderness/swelling, and reduced sexual interest/ability may also occur as a result of lowered testosterone levels. Talk to your doctor if these effects occur. In girls, when this medication is used regularly, it is expected that the menstrual period will stop (or decrease to light bleeding/spotting during the first 2 months). Tell your doctor promptly if regular periods continue after 2 months of treatment with leuprolide. Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects. During the first few weeks of treatment, your hormone levels will actually increase before they decrease. This is a normal response by your body to this drug. This may result in a temporary increase in your symptoms for a few weeks. In men, an increase in testosterone levels at the beginning of treatment may sometimes result in new or worsening symptoms for a few weeks. If you have prostate cancer that has spread to the spine or caused urinary blockage, you may require closer monitoring by your doctor, especially when you first start treatment. Tell your doctor immediately if you experience any of the following serious side effects: bone pain, numbness/tingling/weakness of the arms/legs, blood in the urine, painful/difficult urination, unusual weakness, inability to move. Tell your doctor immediately if any of these unlikely but serious side effects occur: mental/mood changes (e.g., depression, thoughts of suicide, mood swings, aggression in children), new/worsening bone pain (in adults), easily broken bones (in adults). Get medical help right away if any of these rare but serious side effects occur: chest discomfort/pain, irregular heartbeat, weakness on one side of the body, slurred speech. Rarely, a very serious problem with your pituitary gland (pituitary apoplexy) may occur, usually in the first hour to 2 weeks after your first injection. Seek immediate medical attention if any of these very serious side effects occur: sudden severe headache, sudden severe mental/mood changes (e.g., severe confusion, difficulty concentrating), vision changes, severe vomiting, fainting. A very serious allergic reaction to this drug is rare. However, seek immediate medical attention if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing. This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist. In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088. In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.