Side Effects of Mycophenolate
Mycophenolate mofetil (MMF) has numerous side effects affecting multiple organ systems, with gastrointestinal, hematologic, and infectious complications being the most common and clinically significant adverse reactions requiring monitoring and potential dose adjustment or discontinuation. 1
Major Side Effect Categories
Gastrointestinal Effects
- Diarrhea (most common GI effect)
- Nausea, vomiting, anorexia
- Abdominal pain, dyspepsia
- Constipation
- Risk of intestinal perforations and GI bleeding 2
- Villous atrophy (can mimic celiac disease) 3, 4
- Colitis with Crohn's disease-like changes 5
Hematologic Effects
- Leukopenia
- Anemia (including pure red cell aplasia)
- Thrombocytopenia
- Neutropenia 1
Infectious Complications
- Increased risk of opportunistic infections
- Viral infections (particularly concerning with prolonged use)
- Progressive multifocal leukoencephalopathy (rare but serious) 1
- Bacterial infections (including Staphylococcus aureus skin infections) 6
Cardiovascular Effects
- Systemic hypertension
- Peripheral edema
- Tachycardia 1
Dermatologic Effects
- Rash
- Skin neoplasms
- Acne (can be severe enough to require drug discontinuation) 6
Metabolic Effects
- Hypercholesterolemia
- Electrolyte disturbances (hypophosphatemia, hypokalemia, hyperkalemia)
- Hyperglycemia 1
Neurologic Effects
Ocular Effects
- Blurred vision
- Cataracts
- Blepharitis
- Keratitis
- Glaucoma
- Macular abnormalities 1
Genitourinary Effects
- Urinary tract infections
- Hematuria
- Tubular necrosis
- Urinary frequency
- Burning on urination 1
Respiratory Effects
- Increased cough
- Dyspnea
- Respiratory infections
- Pneumonitis
- Fibrosis 1
Special Warnings and Precautions
Pregnancy Risks
- FDA black box warning for use during pregnancy
- Teratogenic and embryocidal effects
- Increased risk of miscarriage in first trimester
- Higher risk of birth defects
- Contraindicated during pregnancy and lactation 1, 2
Malignancy Risk
- Increased risk of lymphoma
- Increased risk of skin cancers
- Risk of other malignancies with prolonged use 1
Monitoring Requirements
- CBC monitoring: weekly for first month, twice monthly for second and third months, monthly for remainder of first year
- Thereafter, CBC should be monitored every 1-3 months as long as therapy continues
- Liver function tests should be done at least monthly
- MPA blood levels may be obtained if GI intolerance develops 1, 7
Drug Interactions
- Activated charcoal, aluminum/magnesium antacids, cholestyramine, and iron can inhibit absorption
- Avoid coadministration with azathioprine (increased purine metabolism inhibition)
- Can increase plasma concentration of acyclovir or ganciclovir
- May decrease effectiveness of hormonal contraceptives
- Live vaccines should be avoided 1, 7
Management of Side Effects
- For GI side effects: Consider switching to enteric-coated mycophenolate sodium formulation 7
- For severe diarrhea: Check MPA levels and consider dose reduction 1, 4
- For hematologic effects: Monitor CBC regularly and adjust dose if significant cytopenias develop 1
- For skin manifestations: May require specific treatment and possible drug discontinuation 6
Patient Education Points
- Report fever or signs of infection immediately
- Report unexplained bleeding or bruising
- Avoid live vaccines while on therapy
- Use effective contraception (women should use two methods)
- Do not donate blood during therapy and for at least 6 weeks after stopping
- Males should not donate sperm during therapy and for 90 days after stopping 2
By understanding these side effects and implementing appropriate monitoring, many adverse reactions can be detected early and managed effectively to improve patient outcomes and medication adherence.