Mycophenolate Mofetil (Cellcept) Risks, Warnings, and Complications

RISKS DURING PREGNANCY: Taking mycophenolate mofetil during pregnancy is linked to an increased risk of miscarriage in the first trimester and an increased risk of birth defects, including external ear and facial anomalies such as cleft lip and cleft palate, as well as abnormalities of the heart, kidneys, nervous system, esophagus, and limbs. 

Your healthcare provider will counsel you about these risks if you are a female of reproductive age. You will need to have a negative pregnancy test before starting treatment with mycophenolate mofetil, once more 8-10 days later, and throughout treatment. Your doctor will also discuss acceptable birth control methods while you are on this immunosuppressant drug. Mycophenolate mofetil can make oral contraceptives (birth control pills) less effective, so you will need other birth control methods for backup if you are on birth control pills.

Male partners of females who can become pregnant should use effective birth control for at least 90 days after the last dose of mycophenolate mofetil.

INCREASED RISK OF CANCER: Immunosuppressants, including mycophenolate mofetil, increase the risk of developing lymphomas, skin cancers, and other malignancies. The risk increases with higher doses and longer duration of treatment. 

To lower your risk of skin cancer, avoid unnecessary exposure to sunlight and artificial UV light. Wear protective clothing and use a broad-spectrum sunscreen with at least 30 SPF (sun protection factor).

Seek immediate medical care if you develop any new lumps or bumps, skin sores or moles, fever, fatigue, or unexplained weight loss. 

POST-TRANSPLANT LYMPHOPROLIFERATIVE DISORDER (PTLD): Post-transplant lymphoproliferative disorder (PTLD) is a life-threatening complication of organ transplant that can occur in people receiving mycophenolate mofetil with other anti-rejection drugs. Most of the cases of PTLD are associated with Epstein-Barr Virus (EBV) infection and occur in the first year after transplant. Seek immediate medical attention for fever, malaise, fatigue, and flu-like symptoms. 

SERIOUS INFECTIONS: Immunosuppressant drugs such as mycophenolate mofetil suppress the immune system. A weakened immune system can affect the body’s ability to fight infections. Taking mycophenolate mofetil is associated with an increased risk of protozoal, fungal, bacterial, and viral infections, including opportunistic infections. The risk increases with higher doses and a longer duration of the entire Cellcept treatment. These serious infections may lead to hospitalizations and can even be fatal. Some of the serious infections that can occur in people taking immunosuppressants include blood infections, BK virus (polyomavirus-associated nephropathy or PVAN), cytomegalovirus (CMV), JC virus-associated progressive multifocal leukoencephalopathy (PML), reactivation of hepatitis B and C, brain infection, and respiratory tract infections such as COVID-19.

Seek immediate medical attention for any signs of fungal, viral, or bacterial infections during mycophenolate mofetil treatment, including fever, chills, sore throat, cough, unusual bleeding or bruising, frequent urination, pain or burning with urination, slow healing wounds or sores, weakness, tiredness, flu-like symptoms, white patches in the mouth, cold sores, headache, or earache.

BLOOD DYSCRASIAS: Patients receiving mycophenolate mofetil can develop low blood cell counts, including severe neutropenia (decreased numbers of neutrophils, which are a type of white blood cell) and pure red cell aplasia (PRCA) (decreased red blood cells). If you develop these complications, the dose of mycophenolate mofetil may need to be reduced and diagnostic tests performed. Your doctor will monitor blood cell counts regularly while you are receiving the immunosuppressant drug. Call your doctor immediately if you have any signs of infection, unexpected bruising, or bleeding. 

GASTROINTESTINAL COMPLICATIONS: There are reports of gastrointestinal bleeding, ulcers, and perforation during clinical trials with mycophenolate mofetil. Seek immediate medical care if you develop severe stomach pain or notice blood in vomit, coffee grounds vomit, or black, tarry stools. 

HEREDITARY DEFICIENCIES: The use of mycophenolate mofetil, which is an inosine monophosphate dehydrogenase (IMPDH) inhibitor, is not recommended in patients with hereditary deficiencies such as hypoxanthine-guanine phosphoribosyl-transferase deficiency (HGPRT), for example, Lesch-Nyhan syndrome and Kelley-Seegmiller syndrome. The use of mycophenolate mofetil in people with these inherited disorders can lead to the worsening of disease symptoms due to overproduction and accumulation of uric acid. This can cause gout and acute arthritis symptoms, tophi, kidney stones, and kidney failure. 

ACUTE INFLAMMATORY SYNDROME: There are reports of acute inflammatory syndrome (AIS) with mycophenolate mofetil. This is a paradoxical pro-inflammatory reaction with signs and symptoms such as fever, joint pain and stiffness, muscle pain, and increased inflammatory markers (erythrocyte sedimentation rate and C-reactive protein) on blood tests. The symptoms of AIS can occur within weeks to months of starting treatment or after an increase in the dose of mycophenolate mofetil. Symptoms and inflammatory markers usually improve within 24-48 hours of discontinuing treatment. 

IMMUNIZATIONS: Live attenuated vaccines should not be taken during treatment with mycophenolate mofetil, for example, intranasal influenza, MMR (measles, mumps, rubella), oral polio, BCG, varicella, yellow fever, and TY21a typhoid vaccines. Talk to your healthcare team about immunizations. 

LOCAL REACTIONS WITH RAPID INTRAVENOUS INFUSION: Mycophenolate mofetil intravenous injection is given over a period of 2 hours. If it is given rapidly or as a bolus, there is an increased risk of local adverse reactions such as phlebitis (vein inflammation) and thrombosis (blood clotting). 

RISKS IN PHENYLKETONURIA PATIENTS: Mycophenolate mofetil oral suspension contains aspartame, which is a source of phenylalanine, which is harmful to people with phenylketonuria (PKU). 

BLOOD DONATION: Do not donate blood during treatment with mycophenolate mofetil and for at least 6 weeks after stopping the medicine. This is to avoid your blood or blood products being given to a pregnant female or a female with reproductive potential. 

SEMEN DONATION: Men taking mycophenolate mofetil should not donate semen during treatment and for at least 90 days after discontinuation of treatment. 

IMPAIRED ABILITY TO DRIVE: Mycophenolate mofetil can cause dizziness, confusion, blood pressure problems (low blood pressure), and tremors (uncontrollable shaking), which can impact the ability to drive and use machinery safely. Avoid driving or using heavy machinery if you experience these side effects.