Publication:

Pattern of adverse drug reactions and serum level of maintenance lithium treatment in patients with bipolar affective disorder: a cross-sectional study in Eastern Nepal

Background Benefits of lithium maintenance therapy in bipolar affective disorder (BPAD) are restricted by adverse drug reactions (ADRs) and low therapeutic index. The same dose of lithium has sub-therapeutic, therapeutic and supra-therapeutic serum level in different patients. The objective of this study was to describe the pattern of ADR and serum concentration of maintenance dose of lithium in patients with BPAD.

Methods A cross-sectional study was conducted in patients diagnosed with BPAD and taking lithium monotherapy 900 mg daily at least for 6 months at outpatient department of psychiatry, B. P. Koirala institute of health sciences. Sociodemographic profile and relevant laboratory investigations were recorded on a self-designed proforma. Chi square test, ANOVA test and student’s t test were used for analysing the data at p value <0.05.

Results Out of 123, 64 (52.0%) were female. Serum concentration ranged from 0.31 to 1.51 mmol/l with mean of 0.803 mmol/l and was in therapeutic range in 104 (84.6%) patients. At least one ADR was seen in 81 (65.9%) patients and hand tremor (43.6%) was the commonest ADR. Hypothyroidism and hyperthyroidism were seen in 9 (6.8%) and 6 (4.5%) patients, respectively. Occurrence of ADRs were more in female and was significantly significant (P value <0.05).

Conclusions The serum level of lithium 900 mg/day varied widely and was in therapeutic range in majority of the patients. Prevalence of ADRs was 65.9%. Occurrence of ADRs were significantly more common in female patients and supra-therapeutic serum concentration of lithium. A prospective long-term study should be conducted to validate the study findings.