Methotrexate Dosing Error: Weekly Drug Taken Daily for Ten Days
Methotrexate Dosing Error: Weekly Drug Taken Daily for Ten Days - Rheumatology clinical simulation case. A 62-year-old woman with rheumatoid arthritis...
A 62-year-old woman with rheumatoid arthritis presents with worsening painful oral ulcers, profound fatigue, nausea, low-grade fever, and bruising after inadvertently taking her weekly methotrexate dose every day for ten consecutive days. A 62-year-old retired schoolteacher with a 14-year history of rheumatoid arthritis managed on methotrexate, hydroxychloroquine, and low-dose prednisone. She lives alone and has been independent with her medications until this week.
Acute Resuscitation Milestones & Priorities
Clinical phases and key interventions encountered in this emergency module:
Triage, Recognition, and Immediate Cessation
Pancytopenia Recognition and Marrow Support
Renal Rescue, Hepatoprotection, and Mucosal Care
Recovery, Counseling, and Safe Discharge Planning
High-Yield Clinical Pearls
Methotrexate toxicity from daily dosing errors requires immediate drug cessation plus folinic acid (leucovorin) rescue, since folic acid cannot bypass the dihydrofolate reductase block.
Aggressive IV hydration and urinary alkalinization reduce intratubular methotrexate precipitation, protecting residual renal function.
Glucarpidase is reserved for refractory methotrexate levels (> 1 micromol/L at 24-48 hours) with renal failure, not as first-line therapy.
G-CSF shortens neutropenia duration and reduces infection-related mortality in drug-induced agranulocytosis.
NSAIDs must be avoided in methotrexate toxicity because they impair renal clearance and elevate serum drug levels.
Safe discharge from a methotrexate dosing error requires systemic safeguards (blister packs labeled 'weekly', caregiver verification, teach-back) rather than verbal warning alone.
Test Your Clinical Reasoning in Real Time
Step into the active clinician role for this case. Order diagnostic tests, analyze live laboratory panels, and navigate branching clinical decisions with real-time feedback.