What are the side effects of mycophenolate?

Mycophenolate Side Effects

Mycophenolate mofetil has numerous side effects affecting multiple organ systems, with gastrointestinal effects, hematologic abnormalities, and increased risk of infections being the most common and clinically significant adverse reactions. 1

Major Side Effect Categories

Gastrointestinal Effects

• Nausea, anorexia, vomiting, dyspepsia, abdominal pain, diarrhea, and constipation are common 1
• Diarrhea can be severe, requiring dose reduction or discontinuation, and may present with histologic features resembling inflammatory bowel disease or graft-versus-host disease 2, 3
• High mycophenolate blood levels may be associated with increased risk of diarrhea 4
• Gastrointestinal bleeding, intestinal perforations, and gastric/duodenal ulcers can occur 5

Hematologic Effects

• Anemia, leukopenia, thrombocytopenia, and rarely pure red cell aplasia 1
• Regular monitoring of CBC is required: weekly for the first month, twice monthly for months 2-3, and monthly thereafter 1
• Bone marrow suppression may necessitate dose reduction or discontinuation 6

Infectious Complications

• Increased risk of opportunistic infections due to immunosuppression 1, 5
• Progressive multifocal leukoencephalopathy has been reported (FDA alert) 1
• Patients should monitor temperature frequently and report fever immediately 1

Cardiovascular Effects

• Systemic hypertension, peripheral edema, and tachycardia 1

Dermatologic Effects

• Rash and increased risk of skin neoplasms 1
• Patients should monitor for changes in moles or new skin lesions 5

Neurologic Effects

• Headache, tremor, insomnia, dizziness, and anxiety 1
• Patients should report any neurologic symptoms promptly 1

Metabolic/Endocrine Effects

• Hyperglycemia, hypercholesterolemia, electrolyte abnormalities (hypophosphatemia, hypokalemia, hyperkalemia) 1
• Cushingoid changes and hirsutism may occur 1

Genitourinary Effects

• Urinary tract infections, hematuria, tubular necrosis 1
• Urinary frequency, burning on urination, kidney stones 1
• In women: vaginal burning and bleeding 1

Respiratory Effects

• Increased cough, dyspnea, respiratory infections 1
• Risk of pneumonitis and fibrosis 1

Musculoskeletal Effects

• Bone pain, leg cramps, myalgias, hand cramps 1
• Acute inflammatory syndrome with joint stiffness, joint pain, or muscle pains 5

Pregnancy Risks

• FDA black box warning for use during pregnancy due to teratogenic and embryocidal effects 1
• Classified as FDA pregnancy category D 1
• Severe cranial, facial, and cardiac abnormalities have been reported in neonates 1
• Patients should avoid pregnancy while taking mycophenolate 1

Drug Interactions

• Absorption is inhibited by activated charcoal, aluminum/magnesium salts, cholestyramine, colesevelam, colestipol, and iron 1
• Coadministration with azathioprine may increase purine metabolism inhibition 1
• Increases plasma concentration of acyclovir or ganciclovir, especially with renal impairment 1
• May decrease effectiveness of hormonal contraceptives 1
• Live vaccines should be avoided during treatment 1

Monitoring Recommendations

• CBC counts: weekly for first month, twice monthly for months 2-3, monthly for remainder of first year 1
• Renal and hepatic profiles should be monitored regularly 1
• Mycophenolate blood levels may be checked if GI intolerance develops 1
• Patients should be monitored for signs of infection and malignancy 5

Special Considerations

• Patients should not donate blood during therapy and for at least 6 weeks after discontinuation 5
• Males should not donate semen during therapy and for 90 days after discontinuation 5
• May impair driving ability due to somnolence, confusion, dizziness, tremor, or hypotension 5

By understanding these side effects and implementing appropriate monitoring, clinicians can optimize the safety profile of mycophenolate therapy while maintaining its immunosuppressive benefits.