Section 07 · Monograph

Mycophenolate mofetil

Reviewed Nov 2026FDA label

CellCeptPurine synthesis inhibitor

Black Box Warning

EMBRYO-FETAL TOXICITY: use during pregnancy is associated with increased risk of first-trimester pregnancy loss and congenital malformations. Females of reproductive potential must have a negative pregnancy test before starting, use two forms of effective contraception before/during/for 6 weeks after therapy, and CellCept is only available through a restricted REMS program
MALIGNANCIES: increased risk of developing lymphoma and other malignancies, particularly of the skin, due to immunosuppression
SERIOUS INFECTIONS: increased susceptibility to bacterial, viral (CMV, BK virus, hepatitis B/C reactivation), fungal, and protozoal infections, including opportunistic infections that may be fatal

Prophylaxis of organ rejection in adult and pediatric patients (≥3 months) receiving allogeneic renal transplants, in combination with cyclosporine (or tacrolimus) and corticosteroidsFDA-labeled
Prophylaxis of organ rejection in adult patients receiving allogeneic cardiac transplants, in combination with cyclosporine and corticosteroidsFDA-labeled
Prophylaxis of organ rejection in adult patients receiving allogeneic hepatic transplants, in combination with cyclosporine and corticosteroidsFDA-labeled

Steroid-sparing immunosuppressant for myasthenia gravis (MG), typically as adjunct to corticosteroids to allow steroid dose reduction; typical MG dosing 1000 mg twice daily (target 2000-3000 mg/day), started with slow titration; onset of clinical benefit delayed, often 6-12 monthsOff-label
Other autoimmune neurologic and rheumatologic conditions (e.g., lupus nephritis, autoimmune encephalitis)Off-label

Prodrug rapidly hydrolyzed to mycophenolic acid (MPA), its active moiety
MPA is a potent, selective, reversible, non-competitive inhibitor of inosine monophosphate dehydrogenase (IMPDH), a key rate-limiting enzyme in de novo purine synthesis
T and B lymphocytes are highly dependent on de novo purine synthesis for proliferation, giving relative lymphocyte selectivity
Inhibition of IMPDH suppresses B- and T-lymphocyte proliferation, antibody formation, and cell-mediated immune responses relevant to both allograft rejection and autoantibody-mediated disease such as MG

Cardiac transplant (adult): 1.5 g PO/IV twice daily (3 g/day total)
MG off-label dosing: initiate 500 mg twice daily x 2-4 weeks, titrate to target 1000-1500 mg twice daily (2-3 g/day) as tolerated
IV formulation: infuse over ≥2 hours; never give as bolus or rapid injection
Take on an empty stomach when feasible; separate from antacids and bile-acid resins by ≥2 hours

Renal transplant (adult): 1 g PO/IV twice daily (2 g/day total)
Renal impairment (GFR <25 outside immediate post-transplant period): avoid doses >1 g twice daily

Hypersensitivity to mycophenolate mofetil, mycophenolic acid, or mycophenolate sodium
Hypersensitivity to polysorbate 80 (relevant to IV formulation)
Pregnancy (except when there is no other alternative to treat the condition)

Antacids with magnesium/aluminum hydroxide and proton pump inhibitors reduce MPA absorption/exposure
Cyclosporine reduces MPA exposure by interrupting enterohepatic recirculation
Cholestyramine and other bile-acid-binding resins substantially reduce MPA levels — avoid coadministration
Live attenuated vaccines should be avoided during therapy
Acyclovir/ganciclovir and mycophenolate may each increase the other's plasma concentration via competition for renal tubular secretion
Azathioprine and other myelosuppressive agents increase risk of additive hematologic toxicity

CBC with differential: weekly for month 1, twice monthly for months 2-3, then monthly through month 12 (transplant schedule); similar vigilance recommended for MG, especially during titration
Renal and hepatic function periodically
Signs/symptoms of infection at every visit
Pregnancy test before initiation and periodically in females of reproductive potential
Clinical assessment of MG symptoms/strength to gauge steroid-sparing effect
Skin exams for malignancy surveillance with long-term use

Boxed warning for embryo-fetal toxicity: increased risk of first-trimester miscarriage and major congenital malformations
Contraindicated in pregnancy except when no alternative treatment exists
Available only through the Mycophenolate REMS program due to fetal risk
Females of reproductive potential require a negative pregnancy test immediately before starting and two reliable forms of contraception before/during/for 6 weeks after stopping
Not recommended during lactation — present in animal milk and human data are limited; potential for serious adverse reactions in a breastfed infant