Health Library

Testosterone (By mouth)

Testosterone Undecanoate (tes-TOS-ter-one un-dek-a-NOE-ate)

Treats low or no testosterone levels.

Brand Name(s):

When This Medicine Should Not Be Used:

How to Use This Medicine:

Capsule

• Take your medicine as directed. Your dose may need to be changed several times to find what works best for you.
• It is best to take this medicine with food or milk.
• This medicine should come with a Medication Guide. Ask your pharmacist for a copy if you do not have one.
• Missed dose: Take a dose as soon as you remember. If it is almost time for your next dose, wait until then and take a regular dose. Do not take extra medicine to make up for a missed dose.
• Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

• Some medicines can affect how testosterone works. Tell your doctor if you are using any of the following:
  • Insulin
  • Blood thinner (including warfarin)
  • Pain or cold medicine
  • Steroid medicine (including dexamethasone, hydrocortisone, methylprednisolone, prednisolone, prednisone)

Warnings While Using This Medicine:

• Tell your doctor if you have liver disease, kidney disease, heart or blood vessel disease, blood disease, lung disease, diabetes, an enlarged prostate, heart failure, obesity, sleep apnea, high cholesterol, thyroid problems, or a history of heart attack or stroke.
• This medicine may cause the following problems:
  • High blood pressure
  • Increased number of red blood cells
  • Increased risk of prostate cancer
  • Blood clot in your leg or lung
  • Increased risk of heart attack or stroke
  • Liver problems
  • Changes in mood or behavior, including thoughts of suicide
• This medicine can be habit-forming. Do not use more than your prescribed dose. Call your doctor if you think your medicine is not working.
• This medicine may lower your sperm count (with large doses). Talk with your doctor before using this medicine if you plan to have children. Some men who use this medicine have become infertile (unable to have children).
• Your doctor will do lab tests at regular visits to check on the effects of this medicine. Keep all appointments.
• Keep all medicine out of the reach of children. Never share your medicine with anyone.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

• Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
• Bone or muscle pain
• Change in how much or how often you urinate, trouble urinating
• Chest pain, cough, trouble breathing, tightening of your throat, unusual sweating, bluish-colored skin
• Confusion, constipation, dry mouth, weight loss
• Dark urine or pale stools, nausea, vomiting, loss of appetite, stomach pain, yellow skin or eyes
• Dizziness, lightheadedness, or fainting
• Numbness or weakness in your arm or leg, or on one side of your body, pain in your lower leg, sudden or severe headache, problems with vision, speech, or walking
• Rapid weight gain, swelling in your hands, ankles, or feet
• Unusual mood or behavior, thoughts of killing oneself
• Unusual bleeding, bruising, or weakness

If you notice these less serious side effects, talk with your doctor:

• Enlarged, swollen, or painful breasts in men
• More erections than usual or erections that last a long time
• Runny or stuffy nose, sore throat

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Last Updated: 9/6/2024