What to Know About CellCept (Mycophenolate Mofetil)

An Immunosuppressant for Organ Transplants and Some Autoimmune Diseases

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CellCept (mycophenolate mofetil, or MMF) is a common treatment for people who have had organ transplants. It is an immunosuppressant drug that tamps down the immune system and helps to prevent organ rejection. Most people who have had organ transplants take CellCept both right after transplantation and for the long term.

CellCept is sometimes used to treat certain autoimmune conditions, such as lupus, vasculitis, and inflammatory bowel disease (IBD). The drug can be taken orally as a tablet or liquid or through an intravenous (IV) line.

Serious man ready to take a pill


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Uses

In 1995, the Food and Drug Administration (FDA) approved CellCept as an immunosuppressant therapy to be used after a kidney transplant. Today it is specifically approved to be used for kidney, heart, or liver transplants. 

Someone who has received an organ transplant needs to be on lifelong therapies that suppress their immune system to prevent organ rejection—a dangerous condition in which the body’s immune system attacks the new organ because it doesn’t recognize it.

If a person goes into organ rejection, the new organ they have received might not work well, and it might even need to be removed.

To prevent organ rejection, people who have received organ transplants take multiple drug therapies to tamp down their immune systems (called immunosuppressives). CellCept is never taken on its own for this purpose; it is always combined with other immunosuppressive medications.

Off-Label Uses

Technically, CellCept is approved only for certain types of organ transplants. However, it is also often used as an immunosuppressant drug for other types of solid organ transplants (for example, a lung transplant).

Graft-Versus-Host Disease

CellCept can also be given to people who have received stem cell transplants. When used for this purpose, it is given before the stem cell transplant and for a period after to prevent graft-versus-host disease, a condition in which the donor cells attack the person's tissue. CellCept can also be used in people who develop graft-versus-host disease.

Autoimmune Conditions

CellCept is sometimes prescribed off-label to treat medical conditions that involve the immune system.

It is important to treat autoimmune conditions that cannot be reversed in other ways. When the immune system is not working correctly, the body might start attacking itself. CellCept can help tone down an overactive immune response. 

Some of the medical conditions that can be treated with CellCept are:

CellCept can also be combined with other immunosuppressant therapies to treat autoimmune conditions.

Before Taking

CellCept should be used only after you have received an organ transplant or after you have been diagnosed with a medical condition for which it is prescribed off-label. The first dose is usually given within the first 24 hours of the transplant.

You will need to discuss the risks and benefits of using CellCept with your healthcare provider. In some cases, there might not be a better treatment choice; the options available may carry similar risks to CellCept.

Precautions and Contraindications

There are several factors or circumstances in which a person might not be able to take CellCept. If you are unsure about whether CellCept is safe for you, talk to your doctor.

Allergies

People with an allergy to CellCept or any ingredient in the medication should not take it.

Pregnancy and Birth Control

Taking CellCept during pregnancy is not advised unless there are no other treatment options available. Using CellCept during pregnancy is associated with congenital malformations and loss of the pregnancy.

Before starting CellCept, people who could become pregnant should have a pregnancy test. The test should also be repeated eight to 10 days later.

If a patient is pregnant or becomes pregnant while taking mycophenolate and it is decided that they should continue taking the drug for a partial time or duration of the pregnancy, they must work with their provider to enroll in an Risk Evaluation and Mitigation Strategy (REMS) program.


REMS is an online program that informs providers and patients about the increased risks to the fetus (or baby) during pregnancy. It is required by the Food and Drug Administration (FDA).

A person who could become pregnant needs to use an effective contraceptive method, such as an intrauterine device, while they are taking CellCept. However, it's important to note that CellCept may interfere with the effectiveness of oral contraceptive medications.

People are advised not to try to conceive while on CellCept or for 90 days after treatment has ended.

Blood Donation

People taking CellCept should not donate blood while they are on it or for a certain amount of time after they stop taking it.

Special Populations

CellCept has not been as well studied in people over the age of 65. However, it still might be the right treatment choice for some older people. To ensure it is safe and works, the prescribing doctor might need to adjust the dose for these people.

People with certain rare medical disorders should not take CellCept.

  • You should not take CellCept if you have a deficiency in hypoxanthine-guanine phosphoribosyl-transferase (e.g., Lesch-Nyhan syndrome or Kelly-Seegmiller syndrome).
  • People with phenylketonuria cannot take the oral liquid version of CellCept because it contains phenylalanine.

Medication Concerns

Tell your doctor about all the medications you take before you start CellCept. Some drugs can affect how well CellCept works.

If you need to take a medication that could interfere with CellCept, then taking CellCept might not be the best treatment option for you. Your doctor might need to reconsider your dose or reconsider whether you could take a different medication to treat your other health condition.

In other cases, you might be able to take both medications as long as they are not taken at the same time of day.

Some drugs have major interactions with mycophenolate. If you are taking these medications, you will need to discuss the risks and benefits of continuing to take them while you are taking CellCept with your doctor. In some cases, you might be able to time your doses to lessen the risk of interactions.

  • Proton-pump inhibitors like Nexium (esomeprazole)
  • Antacids containing magnesium and aluminum 
  • Certain cholesterol-lowering agents like Questran (cholestyramine)
  • Phosphate-binding medications like Renvela (sevelamer)
  • Certain antiviral drugs: Zovirax (acyclovir), Valtrex (valacyclovir), Cytovene (ganciclovir), Valcyte (valganciclovir)
  • Certain antibiotics: Cipro (ciprofloxacin), Augmentin (amoxicillin plus clavulanic acid), Noroxin (norfloxacin), Rifater (rifampin), Bactrim (Trimethoprim/sulfamethoxazole), Flagyl (metronidazole)

Other Immunosuppressive Therapies

CellCept is very similar to another drug called Myfortic (mycophenolic acid). The two drugs contain the same active ingredient, which means that their effects on the body are similar. However, the binding and packing materials that are used to deliver the active ingredient are different.

Myfortic was developed to reduce some of the stomach upset and other gastrointestinal symptoms that can happen with CellCept. It might be a better option for you if you are having GI side effects.

Myfortic is approved for rejection prophylaxis for people who have had kidney transplants, heart transplants, and liver transplants. However, it is often used off-label for people who have had other types of transplants or certain autoimmune conditions.

CellCept is similar to other immunosuppressive therapies that are taken by people who have received organ transplants. However, it does not work in exactly the same way as these other therapies—they do not work on the same parts of the immune system.

The differences are one reason why doctors prescribe more than one drug to help prevent organ rejection in someone who has had a transplant.

There are several immunosuppressants that are sometimes taken with CellCept.

Drugs that you might be prescribed along with CellCept include:

CellCept is also used in place of certain immunosuppressants. For example, you might have a choice about whether to use CellCept instead of another immunosuppressant called Imuran (azathioprine).

Talk to your doctor about the pros and cons of your specific immunosuppressant regimen, as different agents have slightly different risks and levels of effectiveness.

Dosage

CellCept is available as oral capsules of 250 milligrams (mg) or oral tablets of 500 mg. It can also be taken orally in a liquid form or dispensed via an intravenous line. 

A standard dose is generally between 1 gram and 1.5 grams (1,000 mg to 1,500 mg), taken twice a day.

If you accidentally take too much CellCept, call your doctor or a poison control center right away. 

Your dosage may vary based on your age, your weight, the disease requiring CellCept, your other medical conditions, and other factors.

Your doctor will want to balance the drug’s effectiveness with the drug’s risk of side effects—both of which will increase with the dose.

Even though CellCept contains the same active ingredient as Myfortic, you might not take the same dose of one compared with the other because the absorption and processing of these drugs are not identical. If you need to switch, your doctor will calculate your new dose.

Modifications

The oral form is how most people take CellCept. However, immediately following transplant surgery, people usually receive CellCept through an intravenous line. Eventually, most people transition to oral CellCept. 

How to Take and Store

CellCept tablets or liquid form can be stored at room temperature. Take the exact number of tablets that your doctor has prescribed for you.

If you are taking the liquid version of CellCept, measure out the correct amount with the oral dispenser that comes with your prescription. Intravenous CellCept is usually administered in a medical setting, such as in a hospital.

If you miss a dose, take it as soon as you remember. However, if it is two hours or less before you are scheduled to take your next dose, just wait until then and do not double up. 

Avoid letting CellCept come into contact with your skin or eyes.

Do not open or crush CellCept capsules or tablets. If you have trouble swallowing pills, ask your doctor if you can take the liquid form instead.

Side Effects

CellCept has some common and rare side effects that you should know about before you start taking it.

Common

Some of the more common side effects of CellCept include:

  • Stomach problems like abdominal pain, constipation, diarrhea, and vomiting 
  • Blood pressure problems
  • Swelling of the legs and feet
  • Rash
  • Headache

Infection is also a relatively common side effect. It’s also common for people to have signs of decreased white blood cells (leukopenia) on their blood tests when they are taking CellCept.

Severe 

Rarely, CellCept has caused serious gastrointestinal bleeding. Gastric ulcers and perforations are other rare risks. 

Call your doctor right away if you have sudden and severe pain in your stomach, diarrhea, or if you have pain in your abdomen that does not go away.

CellCept also rarely causes severe problems with the liver. However, most people who have liver problems from CellCept have only mild changes that might be seen on a liver test.

These changes will usually go away if the medication is stopped or the dose is lowered. However, it is still important that doctors check liver function with regular blood tests while a person is taking CellCept.

Warnings and Interactions

Risk of Serious Infection

People receiving immunosuppressants like CellCept have an increased risk of developing certain infections.

For example, they might be more likely to get a bacterial or fungal infection. They might be more prone to certain infections that would not affect someone with a normal immune system. There is also a risk that a viral infection that had been dormant in the body (like hepatitis B) might become active.

These risks are part of taking immunosuppressive medications. Although these medications are highly effective at preventing organ rejection and toning down the immune system response, that also means that the immune system cannot respond as well to certain infections. 

Some people taking CellCept have a greater risk of infection than others. Your risk will depend partly on your dose and on the other immunosuppressives you are taking.

Risk of Low Blood Counts

It’s common for people taking CellCept to have lower than normal levels of white blood cells (neutropenia). That is caused by immunosuppression and is one reason why people taking the drug have a greater risk of infection. However, sometimes these numbers become dangerously low, putting an individual at strong risk of severe infection. 

Decreases in other blood components can cause other symptoms. For example, if your platelets are low, it can cause an increased risk of bruising. 

CellCept also carries a risk that you will not be able to form new red blood cells normally (red cell aplasia). This can cause a very serious type of anemia, and your body might not be able to get all the oxygen it needs.

If these blood counts are very low, you might need your dose reduced, or you might need to stop taking CellCept for a while.

You will likely need regular blood tests while taking CellCept—at least for the first year or so after you start. A test like a complete blood count (CBC) can let your doctor know how effectively your body is making its normal white blood cells, red blood cells, and other blood components. 

Let your doctor know right away if you have any unexpected bleeding, bruising, unusual fatigue, or dizziness, or if you have signs of infection like fever or redness and warmth in an area. If you have these symptoms, it might mean that your blood counts are too low. 

Vaccine Considerations

You should not get a certain type of vaccine called a “live vaccine” while on CellCept. There is a chance you could get an infection from this type of vaccine while you are taking a medication that suppresses your immune system.

Many vaccines do not include a live virus—including all the vaccines currently approved by the FDA to prevent COVID-19

People taking CellCept are immunosuppressed, which makes it even more important that they get all the vaccines recommended by their doctor. Ask your healthcare provider if you are not sure if a certain vaccine is safe for you.

Malignancy Risk

People taking CellCept may have a slightly increased risk of getting certain kinds of cancers, especially skin cancers and lymphomas. The potential increased risk of cancer is a risk for many immunosuppressant drugs, not just CellCept. CellCept may even pose less of a risk than other options.

You can take other steps to reduce your cancer risk. For example, do not use tanning beds if you are taking CellCept and use protective clothing and sunscreen to limit your sun exposure.

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