Testosterone is a naturally occurring sex hormone produced in a man's testicles.

Testosterone implants are used in men and boys to treat conditions caused by a lack of testosterone.

Testosterone implants are not for use in treating low testosterone due to getting older. Testosterone implants have not been shown to be safe and effective for enhancing athletic performance.

Testosterone may also be used for purposes not listed in this medication guide.

You should not be treated with testosterone implant if you have prostate cancer or male breast cancer.

Testosterone implants are inserted under the skin on the back side of your hip area, usually once every 3 to 6 months. The implants slowly release testosterone and are absorbed in your body over time.

You will receive testosterone implants with a minor surgical procedure in a clinic or doctor's office.

Follow your doctor's instructions about caring for your surgical incision after receiving testosterone implants.

You may need frequent medical tests. Even if you have no symptoms, tests can help your doctor determine if testosterone implant is effective.

Testosterone can affect bone growth. Young boys treated with testosterone implants may need x-rays every 6 months to check bone development.

Call your doctor if you have any pain, redness, swelling, tenderness, itching, tingling, bruising, or drainage where the implant was inserted, or if the implant comes through the skin or falls out.

If treatment needs to be stopped, the implants may need to be surgically removed early. Do not try to remove the implants yourself. Your doctor will determine whether you need continued treatment with testosterone implants.

Testosterone implants can affect the results of certain medical tests. Tell any doctor who treats you that you are using this medicine.

You should not be treated with this medicine if you have:

• prostate cancer; or

• male breast cancer.

Being treated with testosterone implants may increase your risk of enlarged prostate or prostatic cancer. Ask your doctor about your individual risk.

Tell your doctor if you have ever had:

• heart problems;

• liver disease; or

• kidney disease.

Testosterone implants are not for use in women, and should never be used in a pregnant woman. Testosterone can harm an unborn baby.

Call your doctor for instructions if you miss an appointment for your testosterone implants.

Since the testosterone implant contains a specific amount of the medicine, you are not likely to receive an overdose.

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Testosterone implants can increase your risk of heart attack, stroke, or death. Get medical help right away if you have:

• heart attack symptoms--chest pain or pressure, pain spreading to your jaw or shoulder, nausea, sweating;

• signs of a blood clot deep in the body--pain, swelling, or warmth in one leg; or

• signs of a blood clot in the lung--chest pain, sudden cough or shortness of breath, dizziness, coughing up blood.

Testosterone implant may cause serious side effects. Call your doctor at once if you have:

• swelling in your ankles or feet, rapid weight gain;

• painful or difficult urination;

• depression, racing thoughts, paranoia, confusion, hallucinations, changes in personality or behavior;

• jaundice (yellowing of the skin or eyes);

• a high fever (above 101.5 degrees F), chills, dizziness, nausea, vomiting;

• skin that feels thick or hard over the area where the implants were placed;

• pain, itching, swelling, bruising, bleeding, or drainage where the implants were placed; or

• if the pellets come out of the skin.

Common side effects of testosterone implant may include:

• having more erections or longer-lasting erections than normal;

• breast swelling and tenderness;

• increased or decreased interest in sex;

• numbness, tingling, burning pain;

• changes in skin color, acne;

• changes in hair growth, baldness;

• nausea, vomiting;

• headache, anxiety, depression; or

• abnormal liver function tests.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Tell your doctor about all your other medicines, especially:

• insulin; or

• a blood thinner--warfarin, Coumadin, Jantoven.

This list is not complete. Other drugs may affect testosterone implants, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.