The Relatinship Between Blood Lithium Concentration And Glomerular Filtration Rate In Patients With Manic Episode Receiving Lithium Treatment

Lithium carbonate is now the drug of choice for treating affective disorders.Unfortunately,lithium has a narrow therapeutic index.At present,there is no effective biological parameters in the clinic,which means that it is difficult to evaluate the lithium metabolism ability.Because there is no effective mehtods to control the lithium dose in the treatment,the toxicity associated with lithium occurs easily and frequently.Pharmacokinetic study found that lithium was excreted almost entirely by being filtered from the glomerulus,which suggested there may have correlations between lithium concentration and glomerular filtration rates(GFR).However,experimental studies on the relationship between lithium level and glomerular filtration rates were reported rarely at home and abroad.For the past few years,it was easy to calculate the estimated glomerular filtration rates(eGFR) by measuring serum creatinine in the study on chronic renal diseases,which was simple and easy to operate.We aimed to explore the relationship betweem blood lithium concentration and GFR,and investigate further whether eGFR possessed the significant clinical value during the safety treatment with lithium or not.Objective:By studying blood lithium concentration and factors associated with lithium metabolism, we attempted to explore the relationship between lithium metabolism and glomerular filtration rates(GFR) in manic patients receiving lithium,and investigate whether eGFR could be used as a predictor to evaluate lithium metabolic ability.Methods : 1 . subjects : Fifty two inpatients with manic episode were recruited.All subjects were measured by CCMD-3 (China Classification of Mental Disorder) including Bech-Rafaelsen manic rating scale(BRMS).In patients BRMS sorces were requested≥6,but no obvious impulsive behavior.2. Serum creatinine(Scr),blood urea nitrogen(BUN),body surface area and plasma sodium concentration were assessed before the administration of lithium.The estimated glomerular filtration rates(eGFR) were calculated from the modification of diet in renal disease(MDRD) by equation.The blood lithium concentration was detected in patients receiving lithium at 1.0g/d for about one week when lithium reached the homeostasis.Correlations between blood lithium concentration and relevant parameters were studied.3.All datas were disposed by SPSS16.0 software.The relation between blood lithium concentration and parameters was measured by Pearson Corralation and Linear Regression Analysis.Results : The blood lithium concentration was 0.2～1.0(0.52±0.18)mmoL/L.Single factor analysis showed that blood lithium concentration was negatively correlated with body surface area(r=-0.33,P =0.02)and eGFR(r=-0.30,P =0.03).Multiple stepwise linear regression analysis also revealed a significant inverse relation between blood lithium concentration and body surface area(β=-0.31,P =0.02),eGFR(β=-0.28,P =0.03).But no correlations were observed between blood lithium concentration and Scr,BUN(P>0.05).Conclusions:1.The blood lithium concentration was negatively associated with eGFR,which supposed that individuals renal function could influence the lithium metabolism ability. 2.eGFR could be used as a predictor to evaluate lithium metabolic ability,which was very important to detect and pay close attention to the special patients who were sensitive to lithium intoxication.3.No correlations were observed between blood lithium concentration and Scr,BUN,which hinted that it was fallibility to judge the lithium metabolism by BUN or Scr which was used extensively in the treatment of affective disorders.