engleski

Monitoring of lithium concentration by spectrophotometric methods in patients with bipolar disorder

Lithium therapy, considered to be the treatment of choice in the prevention and management of bipolar disorder, requires continuous monitoring of drug concentration due to its narrow therapeutic range (0.5-1.2 mmol/L). This study was aimed at analytical evaluation of the ThermoTrace spectrophotometric method for lithium determination on an Olympus AU 640 analyzer, and clinical assessment of the method in the follow up of patients on lithium therapy. Study results showed serial imprecision of 0.8%, day-to-day imprecision of 0.79%, and inaccuracy of 6%-7%. Comparison with dry chemistry colorimetric method (Vitros Li slides, Kodak Ektachem) yielded significant correlation (r=0.955 ; p<0.001). The concentrations of bilirubin up to 500 &#61549; mol/L, lipid up to 12 mmol/L and hemoglobin up to 210 &#61549; mol/L did not interfere with lithium. The sample carryover was 0.77, and reagent carryover 0.04. Lithium concentration was measured in 50 patients aged 23-65, treated with lithium doses of 600 mg and 900 mg per day. Of the four patients on a daily dose of 600 mg, lithium concentration of 0.56 mmol/L was measured in only one patient, and was below therapeutic range in the rest. As these patients exhibited manic symptoms, they were hospitalized and the drug dose was increased to 900 mg/day. Of 46 patients on a daily dose of 900 mg, lithium concentration of 0.01 mmol/L was recorded in three patients, indicating the lack of therapeutic compliance, and these patients were hospitalized to achieve stabilization. In the rest of these patients, the mean lithium concentration was 0.66&#61617; 0.16 mmol/L. Study results pointed to monitoring of serum lithium concentration to be necessary for therapeutic success.

lithium; drug concentration; bipolar disorders

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