11. For 12 years, a 65-year-old patient with bipolar affective disorder has been treated with lithium (Eskalith) 900 mg daily. When oral hydrochlorothiazide (HCTZ) 12.5 mg daily is added for hypertension, the patient develops nausea, vomiting, ataxia, and muscle weakness and the patient's serum lithium level is 2.0 mEq/L. The interaction of the lithium and the thiazide diuretic has induced:
C. increased renal clearance of lithium.
D. reduced renal clearance of lithium.