CellCept (mycophenolate mofetil) is a brand-name drug that’s prescribed to help prevent organ rejection in children and adults. As with other drugs, CellCept can cause side effects, such as diarrhea and vomiting.

CellCept can cause certain side effects, some of which are more common than others. These side effects may be temporary, lasting a few days to weeks. However, if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

These are just a few of the more common side effects reported by people who took CellCept in clinical trials:

Mild side effects can occur with CellCept use. This list doesn’t include all possible mild side effects of the drug. For more information, you can refer to CellCept’s prescribing information.

Mild side effects that have been reported with CellCept include:

These side effects may be temporary, lasting a few days to weeks. However, if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks side effects of the medication. If you develop a side effect while taking CellCept and want to tell the FDA about it, visit MedWatch.

* An allergic reaction is possible after using CellCept. To learn more, see the “Side effect specifics” section below.

CellCept may cause serious side effects. The list below may not include all possible serious side effects of the drug. For more information, you can refer to CellCept’s prescribing information.

If you develop serious side effects while taking CellCept, call your doctor right away. If the side effects seem life threatening or you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Serious side effects that have been reported, and their symptoms include:

  • Stomach problems, such as bleeding, ulcers, or perforation (a hole in the stomach or intestinal wall) Symptoms can include:
  • Leukopenia and neutropenia (low counts of certain white blood cells). Having a low white blood cell count usually doesn’t cause symptoms, but this can increase your risk of infection.*
  • Severe anemia (very low red blood cell count). Symptoms can include:
    • shortness of breath
    • lightheadedness
    • pale complexion
    • fast or irregular heartbeat
  • Acute inflammatory syndrome. Symptoms can develop weeks to months after starting treatment or after a dosage change and may include:
    • muscle pain
    • joint pain
    • joint stiffness
    • fever
  • Depression. Symptoms may include:
    • fatigue
    • changes in sleep or appetite
    • loss of interest in your typical activities
    • difficulty concentrating
  • Thrombocytopenia (low platelet count). This condition may increase your risk of bleeding.
  • Risk of harm if used during pregnancy.†
  • Risk of serious infections*
  • Risk of certain types of cancer.*
  • Severe allergic reaction.‡

* CellCept has a boxed warning for this side effect. This is the most serious warning from the FDA. To learn more, see the “Side effect specifics” section below.
† CellCept has a boxed warning for this side effect. This is the most serious warning from the Food and Drug Administration (FDA). To learn more, see the “Precautions for CellCept” section below.
‡ An allergic reaction is possible after using CellCept. To learn more, see the “Side effect specifics” section below.

CellCept is FDA-approved in children ages 3 months and older to help prevent organ rejection. It can be prescribed in combination with other immunosuppressive drugs after a liver, heart, or kidney transplant.

The side effects in children taking CellCept are similar to the side effects reported in adults. However, some side effects occurred more often in children than adults in clinical trials. These side effects include:

Talk with your child’s doctor if you have any concerns about side effects your child may experience while taking CellCept.

CellCept may cause several side effects. Here are some frequently asked questions about the drug’s side effects and their answers.

Can CellCept cause long-term side effects?

It’s possible to have long-term effects from CellCept treatment. Side effects can start at any time during treatment or continue even after you’ve stopped using the drug.

Because CellCept weakens your immune system, there’s a risk of developing infections* at any time during treatment with CellCept. Some infections, such as cytomegalovirus, can be serious. Serious infections may lead to complications that result in hospitalization, or even death.

Taking CellCept can also increase your risk for lymphoma and other cancers, especially skin cancers. There are precautions you can take, such as using sunscreen, to lower your risk. To learn more, see the “Side effects specifics” section below.

Some other long-term side effects that have been reported include:

  • depression
  • risk of pregnancy complications, including problems with fetal development (commonly known as birth defects) and pregnancy loss†

If you have any questions or concerns about long-term side effects of taking CellCept, talk with your doctor.

* CellCept has a boxed warning for this side effect. This is the most serious warning from the Food and Drug Administration (FDA). To learn more, see the “Side effect specifics” section below.
† CellCept has a boxed warning for this side effect. This is the most serious warning from the FDA. To learn more, see the “Precautions for CellCept” section below.

Does CellCept cause eye-related side effects?

Yes, taking CellCept may cause eye-related side effects. Blurry vision was reported in clinical trials, but it isn’t known how often this side effect occurred.

CellCept can increase your risk of certain serious infections, such as a rare viral brain infection called progressive multifocal leukoencephalopathy (PML). One of the possible symptoms of PML is vision changes, such as loss of vision or blurred vision. Other symptoms may include weakness, lack of coordination, or difficulty speaking. If you notice any of these symptoms, talk with your doctor right away.

If you have any questions or concerns about vision changes while taking CellCept, talk with your doctor.

Is weight gain a side effect of CellCept?

It’s possible. Weight gain wasn’t reported as a side effect in clinical trials. However, side effects such as swelling in the ankles, feet, or legs are possible with CellCept. This extra fluid in your body from the swelling can make it seem like you’ve gained weight.

Sudden weight gain can be a possible symptom of organ rejection after undergoing an organ transplant. Other symptoms of organ rejection may include:

  • shortness of breath
  • fatigue
  • fever
  • pain in the area of the transplant

Talk with your doctor if you have any questions or concerns about weight gain while taking CellCept. If you notice sudden weight gain or other symptoms of organ rejection, let your doctor know right away.

Learn more about some of the side effects that CellCept may cause. To find out how often side effects occurred in clinical trials, see the prescribing information for CellCept.

Risk of serious infections

CellCept has a boxed warning about the increased risk for serious infections. Infections were commonly reported in clinical trials of CellCept.

Taking CellCept can increase your risk of developing a serious infection. You may be at higher risk if you are also taking other drugs that can weaken your immune system or are taking a high dose of CellCept. These infections can be bacterial, fungal, or viral. They may lead to serious complications that result in hospitalization, or even death.

Some serious infections that have been reported with CellCept use include:

Symptoms of a serious infection will depend on the type of infection, but may include:

  • muscle aches
  • fever
  • cold symptoms, such as runny nose or sore throat
  • white patches in the mouth or throat
  • headache or earache
  • pain during urination
  • unexpected bruising or bleeding
  • skin rash

What you can do

Contact your doctor right away if you notice any symptoms of infection. They can order any necessary tests to confirm if you have an infection and what type it is. If you do have an infection, your doctor will prescribe medication to treat it. They may also lower your dose of CellCept or ask you to stop taking the medication until your infection has been managed.

If you have concerns about developing a serious infection during treatment with CellCept, talk with your doctor. They can recommend ways to lower your risk.

Risk of cancer

CellCept has a boxed warning for the increased risk of certain cancers, such as lymphoma or skin cancer. This was a rare, but serious side effect in clinical trials of the drug.

The symptoms of lymphoma can be similar to the common cold, but may last for an extended period. Swollen lymph nodes are another common symptom. Some people may not experience symptoms at all. Other symptoms of lymphoma can include:

  • ongoing fever
  • weight loss or reduced appetite
  • night sweat, fever, or chills
  • persistent fatigue

If you have a family history of skin cancer or a lighter skin tone you may be at higher risk of skin cancer during treatment with CellCept.

Signs of skin cancer include moles or spots on your skin that:

  • are new
  • have changed shape or color
  • have grown in size
  • appear scaly, crusty, or discolored

What you can do

To decrease your risk for skin cancer while receiving CellCept treatment, you should limit your time in the sun. It’s important to use a broad-spectrum sunscreen with a high sun protection factor (SPF) when you spend time outdoors. Wearing a hat and clothing that covers your skin, such as a long-sleeved shirt, is also recommended.

Tell your doctor right away if you notice any symptoms of lymphoma or skin changes. They can order tests to determine if your symptoms are caused by cancer.

Allergic reaction

As with most drugs, CellCept can cause an allergic reaction in some people. It appears that skin rash, which can be a symptom of mild allergic reaction, was somewhat common in clinical trials. Serious allergic reactions weren’t reported in studies of CellCept, but have occurred since the drug was approved for use.

Symptoms can be mild or serious and can include:

  • skin rash
  • itching
  • flushing
  • swelling under your skin, typically in your eyelids, lips, hands, or feet
  • swelling of your mouth, tongue, throat, which can make it hard to breathe

What you can do

For mild symptoms of an allergic reaction, call your doctor right away. They may recommend ways to ease your symptoms and determine whether you should keep taking CellCept. However, if your symptoms are serious and you think you’re having a medical emergency, immediately call 911 or your local emergency number.

This drug has boxed warnings. A boxed warning is the most serious warning from the Food and Drug Administration (FDA). It alerts doctors and patients about drug effects that may be dangerous.

Boxed warnings

CellCept has boxed warnings about the risk of harm to a pregnancy, serious infections, and certain cancers. These are the most serious warnings from the Food and Drug Administration (FDA).

Risk of harm to a pregnancy. Use of CellCept during pregnancy can cause pregnancy loss or result in congenital anomalies (commonly known as birth defects). The risk of pregnancy loss is highest during the first 3 months of pregnancy.

For details about the risk of serious infections or cancer, see the “Side effect specifics” section above.

Other precautions

Be sure to talk with your doctor about your health history before you take CellCept. This drug may not be the right treatment for you if you have certain medical conditions or other factors that affect your health. These conditions and factors to consider include:

Stomach problems: Taking CellCept may cause stomach problems, such as stomach ulcers. If you have had stomach problems in the past, including bleeding, ulcers, or perforation, you may be at higher risk while taking CellCept. Talk with your doctor before taking CellCept if you currently have or have had a history of stomach problems. Your doctor may monitor you more closely or recommend a different treatment option for you.

HGPRT enzyme deficiency: If you have a deficiency (low activity) of a certain enzyme called hypoxanthine-guanine phosphoribosyl-transferase (HGPRT), you may be at higher risk for kidney problems or gout. Taking CellCept if you have this enzyme deficiency can cause an increase in uric acid levels in the body. High levels of uric acid can cause gout or kidney problems. Talk with your doctor before starting CellCept if you have an HGPRT enzyme deficiency. They may recommend a different treatment option for you.

Blood donation: You should not donate blood while you are taking CellCept or for at least 6 weeks after your last dose of CellCept. Talk with your doctor if you have any questions about donating blood while taking CellCept.

Semen donation: You shouldn’t donate semen while you are taking CellCept or for at least 90 days after you stop taking the medication. Talk with your doctor if you have any questions about donating semen while taking CellCept.

Phenylketonuria (PKU): PKU is a condition that affects the body’s ability to break down phenylalanine. The liquid suspension form of CellCept contains aspartame (which is a source of phenylalanine). If you have PKU, taking the liquid form of CellCept can make this condition worse. Talk with your doctor about the risks of using liquid CellCept. They can help determine the right treatment option for you.

Allergic reaction: If you’ve had an allergic reaction to CellCept or any of its ingredients, your doctor will likely not prescribe CellCept. Ask your doctor what other medications may be better options for you.

Pregnancy:* It is not safe to take CellCept during pregnancy. Let your doctor know immediately if you become pregnant during treatment with CellCept.

If you become pregnant while taking CellCept, you and your doctor should report your pregnancy to the Mycophenolate Pregnancy Registry. (Mycophenolate is the generic name for CellCept). A pregnancy registry helps gather information on how certain drugs can affect pregnancy. To learn more, call 800-617-8191, visit the registry website, or talk with your doctor.

Breastfeeding: It’s not known if it is safe to use CellCept while breastfeeding your child. Please talk with your doctor if you’re breastfeeding or plan to do so before taking CellCept.

Alcohol consumption: There aren’t any known interactions between CellCept and alcohol. However, drinking alcohol can lead to health problems that can cause extra strain on your transplanted organ, such as high blood pressure or liver damage. Your doctor may recommend you not drink alcohol or limit the amount you drink after a heart, kidney, or liver transplant. If you have questions about drinking alcohol while taking CellCept, talk with your doctor.

* CellCept has a boxed warning for risk of harm to a pregnancy. This is the most serious warning from the Food and Drug Administration (FDA). To learn more, see the “Boxed warnings” section above.

Like many medications, CellCept can cause side effects. Many are mild and may go away on their own within a few days to weeks. In some cases, the medication can cause serious side effects that may require treatment. You should talk with your doctor if any side effects last, are bothersome, or are serious.

If you’d like to learn more about CellCept, talk with your doctor or pharmacist. They can help answer any questions you have about side effects from taking the drug.

Besides talking with your doctor, you can do some research on your own. These articles might help:

Disclaimer: Medical News Today has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.