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

Abstract

<p class="abstract"><strong>Background:</strong> 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.</p><p class="abstract"><strong>Methods:</strong> 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.</p><p class="abstract"><strong>Results:</strong> 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).</p><p class="abstract"><strong>Conclusions:</strong> 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.</p>