What is the recommended dose reduction for a patient with a severe urinary tract infection who is currently taking 360 mg of mycophenolate (mycophenolate mofetil)?

Mycophenolate Dose Reduction in Severe Urinary Tract Infection

For a patient on 360 mg mycophenolate (mycophenolic acid) with a severe urinary tract infection, temporarily interrupt therapy or reduce the dose by 50% (to 180 mg) until the infection is controlled, then resume the full dose. 1

Rationale for Dose Reduction

• Mycophenolate significantly increases the risk of opportunistic infections due to immunosuppression, making dose modification essential during active severe infections 1
• The American Thoracic Society recommends interruption of therapy or dose reduction when patients develop signs or symptoms of infection 2
• Genitourinary effects including urinary tract infections are well-documented adverse effects of mycophenolate therapy 1

Specific Dosing Strategy

• 360 mg mycophenolic acid is equivalent to 500 mg mycophenolate mofetil, which represents minimal maintenance therapy 2
• Since the patient is already on minimal dosing, temporary interruption (holding the dose completely) is the safest approach during severe infection 1
• If complete interruption is not feasible due to underlying disease severity, reduce to 180 mg daily (50% reduction) as an alternative 1

Critical Monitoring During Dose Reduction

• Patients must check temperature frequently and report fever immediately during any infection while on mycophenolate 1
• Monitor CBC counts closely (every 1-2 weeks during acute infection) as both the infection and mycophenolate can cause leukopenia 1
• Assess renal function given the urinary tract infection, as renal impairment increases mycophenolate metabolite accumulation and toxicity risk 1

Important Caveats

• The cumulative number of days with mycophenolate dose reduced below full dose increases rejection risk by 4% per week in transplant patients 3
• However, severe infections take priority over rejection risk in the acute setting, as infections represent immediate mortality risk 1
• Resume full-dose therapy (360 mg) as soon as the infection is adequately controlled with appropriate antibiotics to minimize rejection risk 3

When to Resume Full Dose

• Restart 360 mg once the patient is afebrile for 48 hours, symptoms are improving, and appropriate antibiotic therapy has been initiated 1
• Do not wait for complete resolution of infection before resuming immunosuppression, as this unnecessarily prolongs the period of subtherapeutic dosing 3
• Maintain close surveillance for disease flare when resuming therapy, particularly in autoimmune conditions like lupus nephritis 2

Alternative Consideration

• If gastrointestinal side effects from the infection or antibiotics develop, mycophenolic acid blood levels may be checked to guide dosing rather than empiric reduction 1
• Avoid combining mycophenolate with other myelosuppressive drugs during active infection 2