What Are the Most Common Tacrolimus Side Effects?

Tacrolimus side effects range from mild to severe. Mild side effects include nausea, trouble sleeping and edema of the hands and feet. More severe tacrolimus side effects include numbness and shaking as well as trouble urinating. The drug also increases the amount of potassium in a person's body and in some cases raises the risk for certain types of cancer. Tacrolimus is an immunosuppresent, so a patient taking it is at greater risk for infection.

There are a number of mild tacrolimus side effects. A person on the drug might feel nauseated or might vomit. About one-third of patients will experience itchiness or a rash on their skin. Some might struggle with insomnia or have trouble staying asleep. These usually are considered mild or less severe side effects, but a patient still should report them to his or her doctor, especially if the side effects last for more than a few days.

A few tacrolimus side effects can put a patient at greater risk. Pain when trying to urinate or blood in the urine are signs of a serious side effect and should be reported right away. A person might also find that he or she needs to urinate more often or not at all, which also should be reported to the doctor. In some cases, patients taking tacrolimus are at an increased risk for diabetes, and changes in urination often indicate diabetes.

Tacrolimus can also cause a person to retain potassium, leading to elevated levels in the blood. A patient might need to watch his or her potassium consumption. In general, taking diuretics that cause the body to retain potassium at the same time as tacrolimus should be avoided.

Patients who have had an organ transplant often take tacrolimus to the reduce the risk of the body rejecting the new organ. The immune system is suppressed to prevent rejection, but this also puts a person at greater risk for infections and even cancer. If a patient is exposed to a person who is ill and shows signs of infection, including a sore throat or fever, he or she should see a doctor right away.

Lymphoma, a type of cancer that affects the immune system, and skin cancer are other tacrolimus side effects and risks. Signs of lymphoma include feelings of fatigue, night sweats and swollen lymph nodes. It might cause a person to lose a lot of weight or have trouble breathing. When taking tacrolimus, a person should protect his or her skin from the sun to lower the risk of skin cancer.