Get emergency medical help if you have signs of an allergic reaction: hives, difficult breathing, swelling of your face, lips, tongue, or throat. Testosterone can increase your risk of blood clots, stroke, or heart attack. Get emergency medical help if you have: chest pain, pain, swelling or warmth in your leg, sudden numbness or weakness on one side of the body, slurred speech, feeling short of breath, or trouble breathing. Stop using testosterone and call your doctor at once if you have: pain or swelling in your breasts; sleep apnea (breathing stops during sleep); unusual changes in mood or behavior, new or worsening depression; signs of heart problems or fluid retention--swelling, rapid weight gain, feeling short of breath; liver problems--loss of appetite, nausea, vomiting, stomach pain (upper right side), tiredness, itching, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes); or signs of an enlarged prostate--increased or urgent need to urinate, little or no urination, loss of bladder control, or other problems urinating. Topical testosterone is absorbed through the skin and can cause side effects in anyone who comes into contact with this medicine. You may need to stop using testosterone and call your doctor if a person who has close contact with you develops unexpected sexual changes or male features, aggressive behavior, changes in body hair, increase in acne, or unexpected bone growth. Common side effects may include: redness, irritation, burning, blisters, or itching in the area of the skin where the medicine was applied; back pain; acne, skin color changes; abnormal labs such as increased prostate-specific antigen and increased red blood cell counts; increased blood pressure; headache; mood changes such as depression, strange dreams; erections that are more frequent or that last longer than usual; nausea, vomiting, or diarrhea; or swelling in your lower legs. 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.