Indian Journal of Psychiatry, 2000, 42 (4), 410-414 LONG TERM EFFECTS OF LITHIUM ON GLOMERULAR FILTRATION RATE IN INDIAN SUBJECTS - A CROSS SECTIONAL STUDY BALJINDER SINGH, BHAGWANT R. MITTAL, KAMAL SUD, ANISH BHATTACHARYA, PRATAP SHARAN, SURINDER K. JINDAL & SHRIDHAR D. DEODHAR ABSTRACT Glomerular filtration rate (GFR) was evaluated in thirty patients on lithium and in thirty healthy prospective kidney donors by single compartment, multiple sample plasma clearance method using ""Technetium diethylene triamine pentaacetic acid ("mTC-DTPA). Normality test revealed that dose and treatment duration were skewed and the coefficient of skewness were 0.067 (p<0.0001) and 1.41 (p<0.0001) respectively. Age was marginally skewed (p =0.04) for the control group. At 5% significance level, dose and creatinine were negatively correlated (r =-0.030). whereas age and duration were positively correlated (r =+ 0.53) (single tailed only). Duration and GFR seems to be negatively correlated (r = -0.23), however this correlation did not reach statistically significance level. In the present cross sectional study no significant difference in mean GFR was observed in lithium treated affective disorder patients when compared with the age matched normal subjects. Key words : Lithium, affective disorder, kidney, glomerular filtration rate The potential therapeutic uses of lithium (Li) salts were suggested in the nineteenth century, however, the immense benefit of Li in psychiatric practice has been realized since last 5 decades (Reifman & Wyatt,1980). Lithium treatment may lead to changes in various organ functions and as a part of evaluating the side effects of Li, we have reported that it causes sub-clinical hypothyroidism in a significant number of Li treated patients (Deodhar et al., 1999) and also causes alterations in the blood levels of various essential elements including sodium and potassium in humans (Singh et al.,1998) and animals (Singh et al.,1994). Currently, it is estimated that at any one time about 1:1000 of the populations of most western societies are taking Li prophylaxis for severe bipolar and unipolar affective disorders (Davison et al.,1998). The margin between 'therapy' and 'toxicity' is so narrow that the most serious complications of lithium are acute lithium intoxication (Hansen & Amdisen,1978). As the kidneys almost exclusively excrete lithium, the development of acute Li-intoxication is usually due to decreased renal elimination of this ion. Given the wide spread use of lithium, it was alarming, but perhaps not so surprising, when the 1st report of possible lithium induced chronic histological lesions of the kidneys appeared (Hestbech etal.,1997). Polyurea and polydypsia in-patients on chronic lithium treatment results from impaired urinary concentrating ability. The nephrogenic diabetes insipidus in these patients is because of insensitivity of the collecting ducts to exogenous and endogenous vasopressin, at the level of cellular vasopressin - sensitive adenylate cyclase activity. As the primary mode of excretion of lithium by the kidneys is reassorption from proximal tubules, recent studies have suggested lithium-induced abnormalities in proximal functions (Davison et al.,1989). Walker et al. (1982) reported that parameterrs to evaluate glomerular filtration 410