Anesthetic Considerations for Methotrexate in Rheumatoid Arthritis Surgery
Methotrexate can be safely continued throughout the perioperative period in rheumatoid arthritis patients undergoing elective orthopedic surgery. 1
Perioperative Management
Continue methotrexate through surgery without interruption. The highest quality guideline evidence from the American College of Rheumatology's multinational 3E Initiative explicitly recommends that methotrexate can be safely continued in the perioperative period for RA patients undergoing elective orthopedic surgery. 1 This represents a shift from older, more conservative approaches.
Key Rationale for Continuation
Disease flare prevention: Stopping methotrexate risks precipitating disease flares that can complicate postoperative recovery and rehabilitation. 1
No increased infection risk with continuation: Despite theoretical concerns about immunosuppression, the evidence supports that continuing low-dose weekly methotrexate (typically 15-25 mg/week in RA patients) does not significantly increase postoperative infection rates or impair wound healing when maintained perioperatively. 1
Preoperative Laboratory Assessment
Before proceeding with moderate-to-major surgery, verify the following parameters that should already be monitored in patients on methotrexate:
Hepatic function: Confirm ALT/AST levels are not elevated more than three times the upper limit of normal, as this would indicate need for methotrexate dose adjustment or discontinuation prior to surgery. 1
Renal function: Check creatinine clearance, as methotrexate is primarily renally excreted and renal impairment increases toxicity risk, particularly relevant in the perioperative setting with potential fluid shifts and nephrotoxic anesthetic agents. 2
Complete blood count: Ensure no significant bone marrow suppression (leukopenia, thrombocytopenia, anemia) that could complicate surgical hemostasis or increase infection risk. 1
Anesthetic Drug Interactions
NSAIDs and aspirin: These are commonly co-prescribed with methotrexate in RA patients. Aspirin may affect methotrexate disposition more than other NSAIDs, though this does not typically cause greater toxicity at low doses. 2 Consider this when planning perioperative analgesia.
Avoid trimethoprim-sulfamethoxazole: This combination leads to increased methotrexate toxicity and should be avoided for perioperative antibiotic prophylaxis. 2 Choose alternative prophylactic antibiotics (e.g., cephalosporins).
Probenecid: Should be avoided as it increases methotrexate toxicity through reduced renal clearance. 2
Specific Anesthetic Concerns
Airway management: RA patients may have cervical spine instability (atlantoaxial subluxation), temporomandibular joint involvement limiting mouth opening, or cricoarytenoid arthritis causing airway narrowing—these are disease-related rather than methotrexate-specific concerns but require careful preoperative airway assessment. 1
Pulmonary considerations: Methotrexate can rarely cause pneumonitis, though this is uncommon at low doses used in RA. 1 If present, it would manifest preoperatively and should be identified during preoperative assessment.
Hepatotoxicity monitoring: The gastrointestinal and hepatic side effects of methotrexate (nausea, elevated transaminases) are reduced by folic acid supplementation of at least 5 mg weekly, which should be confirmed as part of the patient's regimen. 1
Postoperative Management
Resume normal methotrexate schedule: If the patient's weekly methotrexate dose falls during the immediate postoperative period and oral intake is compromised, the subcutaneous route can be used as bioavailability is superior to oral administration. 1
Monitor for infection: While continuation is safe, maintain standard postoperative infection surveillance given the patient is on immunomodulatory therapy. 1