Lithium ratio in bipolar patients in Isfahan, Iran

Background: lithium is transferred into the intracellul ar space mainly via sodium-lithium counter transport pathway.this pathway is under genetic control and acts variably in different ethnic groups. with respect to possible genetic differencesin our target population compared to other populations, this study was designed to obtain knowledge on meanlithium ratio (lr) in this population so as to provide a benchmark for adjusting appropriate dosage of prescribed orallithium and plasma concentration of lithium in clinical practice.methods: in this study, 47 (26 male and 21 female) patients with bipolar disorders treated by lithium alone or in combinationwith other drugs at least for 2 weeks were selected by simple random sampling. venous blood samples of selectedpatients were obtained and plasma and rbc lithium concentrations were measured. finally, lr was determinedusing the atomic absorption method.results: mean value of lr in the entire target population and in the group treated with lithium alone was 44.4 ±23.22% and 58.52 ± 14%, respectively. in patients concomitantly treated with lithium and neuroleptic drugs, lr wassignificantly lower than that in all patients. lr in females was higher than that in males. lr in the group treated withlithium alone was significantly higher than figures reported in europeans and americans patients.conclusions: these findings suggest that bipolar patients in this geographical zone ofiran should probably be treatedwith smaller doses of lithium to achieve optimal intracellular therapeutic levels of lithium, compared to levels regardedas therapeutic for europeans and americans.