Adverse Reactions Practice Test

A 45-year-old female (weight 60 kg) treated for bipolar disorder reports excessive thirst, frequent urination, and worsening hand tremor. Current medications: lithium carbonate 300 mg by mouth three times daily (stable dose), ibuprofen 600 mg by mouth three times daily started 1 week ago for dental pain, and quetiapine 200 mg by mouth nightly. Labs: lithium concentration 1.8 mEq/L (high; typical maintenance 0.6–1.0 mEq/L), serum creatinine 1.6 mg/dL (baseline 0.9 mg/dL), sodium 147 mEq/L (high); allergies: none; medical history: bipolar disorder. Which action should the pharmacist take to address this adverse reaction?

A 49-year-old man (80 kg) taking lithium for bipolar disorder presents with worsening tremor, nausea, and slurred speech after starting a new blood pressure medication last week. Current medications: lithium carbonate 900 mg/day by mouth in divided doses, hydrochlorothiazide 25 mg by mouth daily started 7 days ago, quetiapine 200 mg by mouth at bedtime. Labs: lithium level 1.9 mEq/L (high; typical maintenance 0.6–1.2), serum creatinine 1.3 mg/dL (baseline 1.0), sodium 134 mEq/L. Allergies: none. Which medication is causing these symptoms?