Serum Lithium in Patients in Remission of Bipolar Disorder

Abstract

Introduction: Bipolar affective disorder a chronic, and highly disabling psychiatric disorder is one of the leading causes of disability and is estimated to affect more than 1% of the global population irrespective of origin, ethnicity, nationality or socioeconomic status. The effectiveness of lithium in mania and psychotic excitement was proven first proven in 1960 and since then lithium is considered to be a gold standard treatment for bipolar disorder. 
 Material and Method: A total of one hundred thirty five patients with bipolar disorder were enrolled in a prospective study to analyze the serum lithium levels on maintenance dose of lithium. After ethical clearance data was collected from patients attending BG Hospital and Research Centre from July 2013 to July 2019. The patients who were on maintenance treatment with different doses of lithium only were included. These patients were tested for serum lithium concentration as per lithium monitoring guidelines. Serum Lithium, serum electrolytes, height and weight of the patients were recorded. The psychiatric diagnosis was made according to the ICD-10 criteria. Data were computed and analyzed by using SPSS version 21. Parametric and non-parametric statistical technique was applied wherever appropriate. 
 Results: The minimum efficacious serum lithium level in the long-term treatment of bipolar disorder was found at 0.16 mmol/l and maximum serum levels was 1.51 mmol/l. The mean serum lithium level was 0.596 mmol/l with standard deviation of 0.237 mmol/l. 
 Conclusion: There is substantial variation in between the serum lithium levels of patients in remission on long term treatment. The uncertainty about the most efficacious serum lithium level for the long-term treatment of bipolar disorder leads to the suggestion of the treatment of individual patients to be based on clinical response rather than on serum lithium levels.

Association of Plasma Level of Lithium with Clinical Effect in Bipolar Disorder at a Tertiary Center in Eastern Nepal

“…Our study provides statistical evidence of positive relationship between the prescribed dose and serum concentration of lithium and similar results had been demonstrated by Bhandari et al and Lamichhane et al 12,13 It is better to follow the guidelines and have therapeutic drug monitoring of lithium before increasing its dose; otherwise there may be attainment of toxic level of lithium in some patients. Male to female ratio was almost equal to 1 in our study.…”

“…19 Mean BMI was 22.65 Kg/m 2 in our study. In contrast to this, mean BMI was higher (24.96 Kg/m 2 ) in a study by Lamichhane N et al 12 Dose of lithium ranged from 300 to 1200 mg/day and mean dose was 891.9 mg and similar results had been reported in other study. 12 In contrast to this, 600mg was the minimum dose of lithium in an Indian study.…”

“…13 Minimum effective serum level of lithium was 0.26 mmol/L in our study. In contrast to this, minimum effective serum concentration of lithium was 0.16 mmol/L in a study by Lamichhane N et al 12 A higher minimal efficacious serum level (0.4 and 0.39mmol/L) was reported in other studies. 7,13 The guidelines has suggested that serum level of 0.6-0.8 mmol/L is optimum for prophylaxis of BPAD which is higher than our findings.…”

“…Higher number of male had BPAD in other study. 12,14 However, most studies report an almost equal gender ratio in the prevalence of BPAD. 15 Majority of the patients were in 3 rd and 4 th decade of their life with mean age of 32.06±10.80 years.…”

“…Lamichhane et al had reported a lower mean serum level of lithium (0.596 ±0.211 mmol/L) in their study. 12 Interindividual variation in pharmacokinetics and pharmacodynamics, as well as such external factors as diet and concomitant medications can affect serum lithium levels. 21 Therefore it is better to choose the dose of lithium based on individual patients' characteristics in BPAD.…”