Mycophenolate Mofetil

Mycophenolate mofetil is an immunosuppressant approved to prevent organ rejection in transplant recipients. The following uses are supported across all formulations:

• Kidney transplant rejection prevention — for adults and children 3 months and older (oral and IV forms)
• Heart transplant rejection prevention — for adults and children 3 months and older (oral and IV forms)
• Liver transplant rejection prevention — for adults and children 3 months and older (oral and IV forms)

All uses require combination with other immunosuppressant medications. CellCept is available in oral and IV forms. Myhibbin is an oral suspension. Multiple generic formulations (capsules, tablets, oral suspension, IV injection) carry the same indications. The IV form is intended as a short-term alternative — up to 14 days — when a patient cannot take oral medication after transplant surgery.

After you swallow mycophenolate mofetil, your body rapidly converts it into its active form: mycophenolic acid (MPA). MPA works by blocking an enzyme called IMPDH (inosine monophosphate dehydrogenase) that immune cells — T-lymphocytes and B-lymphocytes — depend on to make the building blocks for DNA and to multiply. Without this ability to rapidly divide, these immune cells cannot mount the kind of attack that leads to organ rejection. MPA also interferes with immune cell adhesion and signaling, further dampening the immune response. Importantly, this effect is reversible — immune activity can recover when the drug is stopped.

Mycophenolate mofetil is taken twice daily — generally every 12 hours — by mouth or, in some situations, by intravenous (IV) infusion. It comes in several oral forms: capsules, film-coated tablets, and a liquid suspension (useful for children or patients who cannot swallow tablets). The IV form is used only when a patient cannot tolerate oral medication right after transplant surgery and is typically switched to oral dosing as soon as possible, within 14 days.

• Food does not reduce the total amount absorbed, so it can be taken with or without food — though taking it with food lowers the peak blood level
• Dosing in children is based on body surface area, not a flat dose
• If you miss a dose, follow your prescriber's guidance — do not double up without being told to do so
• Dose may be reduced or temporarily stopped if blood counts fall too low

The most common side effects reported in clinical trials include:

• Diarrhea
• Nausea and vomiting
• Low white blood cell count (leukopenia) — raises infection risk
• Bacterial or viral infections
• Abdominal pain
• Anemia (low red blood cells)
• Swelling (edema)
• Headache and insomnia

More serious reactions to watch for include signs of severe infection (fever, chills, confusion, neurological changes), unusual bruising or bleeding suggesting very low blood counts, and any new skin growths or lumps. Call your transplant team right away if any of these occur.

• Pregnancy — highest priority warning: This drug causes miscarriage and serious birth defects. Women of childbearing age must use reliable contraception during treatment and for 6 weeks after stopping. Pregnancy testing is required before starting. Men should use contraception and avoid donating sperm for at least 90 days after stopping.
• Serious infections: Immune suppression raises the risk of dangerous bacterial, viral, fungal, and parasitic infections, including BK virus (can cause kidney graft loss), JC virus (can cause fatal brain infection PML), CMV, and reactivation of hepatitis B or C. Report any fever, neurological changes, or unusual symptoms immediately.
• Cancer risk: Long-term immune suppression increases the risk of skin cancer and lymphoma (PTLD). Use sunscreen, wear protective clothing, and report any unusual skin changes or lumps.
• Low blood counts (neutropenia/anemia): Regular blood monitoring is essential. Dose reduction or interruption may be needed if counts fall too low.
• Gastrointestinal complications: Bleeding, ulceration, and perforation have been reported — particularly in patients with pre-existing GI conditions. Report severe stomach pain promptly.
• Live vaccines: Avoid live attenuated vaccines while taking this drug.
• Driving and machinery: This drug may affect your ability to drive or operate machinery.

Mycophenolate mofetil interacts with several common drugs that can raise or lower its levels in the body, or be affected by it:

• Antacids (magnesium or aluminum hydroxide) — reduce absorption; take mycophenolate mofetil at least 2 hours before antacids
• Proton pump inhibitors (e.g., lansoprazole, pantoprazole) — lower drug levels; monitor for reduced effectiveness
• Cyclosporine — lowers mycophenolate mofetil levels in the body
• Rifampin and certain antibiotics (aminoglycosides, cephalosporins, fluoroquinolones, penicillins) — may reduce drug levels through gut flora changes
• Cholestyramine and bile acid sequestrants — significantly reduce drug levels by interrupting recycling of the drug
• Telmisartan — increases breakdown of mycophenolate mofetil, lowering its levels
• Isavuconazole — may increase mycophenolate mofetil levels, raising side-effect risk
• Sevelamer and calcium-free phosphate binders — reduce absorption; take mycophenolate mofetil at least 2 hours before these
• Combination oral contraceptive pills — mycophenolate mofetil may reduce their effectiveness; use additional barrier contraception
• Acyclovir, ganciclovir, valacyclovir, valganciclovir — may compete with mycophenolate mofetil's metabolite for kidney elimination, potentially increasing levels of both

This is not a complete list of interactions. Always talk with your doctor or pharmacist before starting, stopping, or changing any medication.

• Allergy to mycophenolate mofetil or mycophenolic acid — this drug is contraindicated if you have had a serious allergic reaction (including anaphylaxis) to it or any ingredient in the product
• Allergy to Polysorbate 80 — the IV formulation is contraindicated; tell your doctor
• Pregnancy or planning pregnancy — must be avoided unless no safer option exists; extensive contraception requirements apply before, during, and after treatment
• Breastfeeding — limited data exist; weigh benefits and risks with your doctor
• Women of reproductive potential — pregnancy testing required before starting; strict contraception required throughout and for 6 weeks after stopping
• Men of reproductive potential — use contraception during treatment and for 90 days after stopping; avoid sperm donation during this period
• Children under 3 months — safety and effectiveness not established below this age
• Older adults — dose selection should account for age-related changes in kidney, liver, or heart function
• Severe kidney impairment — drug levels may be higher; careful monitoring is needed
• HGPRT deficiency (Lesch-Nyhan or Kelley-Seegmiller syndrome) — use should be avoided
• Phenylketonuria (PKU) — the oral suspension contains aspartame; inform your doctor

Taking too much mycophenolate mofetil may cause nausea, vomiting, diarrhea, abdominal pain, and dangerously low white blood cell counts (neutropenia). If overdose is suspected, seek medical care immediately. The drug is not efficiently removed by hemodialysis, but bile acid sequestrants like cholestyramine may help increase its elimination from the body.

The label notes that there is limited formal pharmacodynamic data for mycophenolate mofetil. However, its active metabolite, mycophenolic acid (MPA), measurably suppresses the proliferation of T- and B-lymphocytes, reduces antibody production, and lowers the output of inflammatory signaling molecules (cytokines). It also interferes with immune cell adhesion to blood vessel walls, which may reduce immune cell recruitment to sites of organ rejection. These effects are cytostatic (they slow cell growth) and reversible.

After oral dosing, mycophenolate mofetil is almost completely converted to its active form, mycophenolic acid (MPA), with oral bioavailability of about 94% compared to IV dosing. MPA is extensively bound to plasma proteins (about 97%) and is processed primarily by the liver into an inactive metabolite (MPAG), which is then excreted mainly in the urine. Drug levels in the body are somewhat lower in the first weeks after transplant and tend to rise over the following months, so monitoring may be adjusted accordingly. Food does not meaningfully change total absorption but does lower the peak blood concentration by about 40%.

and Dispensing Information: Store at 25°C (77°F); excursions permitted to 15°C to 30°C (59°F to 86°F). Dispense in light-resistant containers, such as the manufacturer's original containers. Store dry powder at 25°C (77°F); excursions permitted to 15°C to 30°C (59°F to 86°F).