A patient with severe osteoarthritis is due for major surgery. Which medication should be stopped temporarily before the operation?

• A. Theophylline
• B. Lithium
• C. Fluticasone
• D. Montelukast

Answer: (B)

Stop lithium temporarily before major surgery because it is cleared by the kidneys and has a very narrow safety range. In the perioperative setting, fluid shifts, dehydration, and possible changes in kidney perfusion can reduce lithium clearance, causing levels to rise and increasing the risk of toxicity. That toxicity can present with tremor, confusion, ataxia, gastrointestinal symptoms, seizures, and even kidney injury. By withholding lithium during the procedure and until the patient is stable with adequate hydration and oral intake, you minimize these risks. After the surgery and once fluids and kidney function are stable, lithium can be restarted. The other medications listed do not carry the same perioperative toxicity risk that requires stopping for major surgery.