Lithium toxicity after Roux-en-Y bariatric surgery

A 61-year-old woman with medical history significant for morbid obesity, type II diabetes mellitus, nephrogenic diabetes insipidus and bipolar disorder, had been stable on lithium carbonate therapy for several years. She had undergone a Roux-en-Y bypass surgery and, at the time of her surgery, her lithium level was found to be 0.61 mEq/L on a maintenance dose of 600 mg orally twice per day. She was discharged 8 days postoperatively on the same lithium dose, but presented to the emergency department 12 days postoperatively with signs of lithium toxicity. Her lithium level was elevated to 1.51 mEq/L and she was treated for lithium toxicity with supportive care and, ultimately, reduction of her lithium dose. Clinicians should be aware that dramatic and poorly understood changes in drug absorption may occur after bariatric surgery.