Lithium in bipolar and other affective disorders: prescribing practice in the UK

The use of lithium for the treatment of mania, prophylaxis of bipolar disorder and augmentation of antidepressants in treatment-refractory unipolar depression is supported by British Association for Psychopharmacology and National Institute for Health and Clinical Excellence guidelines. We describe prescribing patterns with lithium in a large sample of patients with affective disorders. Data were collected during a baseline clinical audit of the quality of lithium monitoring, conducted by the Prescribing Observatory for Mental Health. Thirty-five National Health Service Trusts submitted data for 2776 patients with a diagnosis of affective illness (ICD10 F30-39), 1919 (69%) of whom had bipolar affective disorder. The last recorded lithium level was below the therapeutic range (<0.4 mmol/L) in one in 10 patients. Co-prescribing was common; 57% of bipolar patients were prescribed an antipsychotic and 77% of those with other affective disorders, an antidepressant. We conclude that serum lithium levels within the therapeutic range are maintained in the majority of patients. A high proportion of patients are co-prescribed other psychotropic drugs; such prescribing is consistent with evidence-based treatment guidelines and may reflect difficulty managing the symptoms of affective disorders with lithium monotherapy. A significant minority of patients prescribed lithium had a sub-therapeutic blood level and so may be at high risk of relapse.