From the Guidelines
I strongly recommend evaluating this patient's lithium levels and considering either a dosage adjustment or adding an antidepressant, such as an SSRI, to address the depressive symptoms, as the current evidence suggests that lithium monotherapy may not be sufficient for bipolar depression. The patient's symptoms of depressed mood and poor motivation while on lithium 750mg BID suggest either subtherapeutic lithium levels or breakthrough depression requiring additional treatment 1. First, order a lithium level to ensure it's within the therapeutic range (0.6-1.2 mEq/L). If levels are low, consider increasing the lithium dose with careful monitoring. If levels are adequate, adding an SSRI like sertraline (starting at 50mg daily) or bupropion (starting at 150mg daily) may help address the depressive symptoms, as supported by the study that found the combination of olanzapine and fluoxetine to be effective for bipolar depression in adults 1. When adding an antidepressant to lithium, start at a lower dose and titrate slowly while monitoring for signs of mood switching or serotonin syndrome. Also, assess for medication adherence, sleep patterns, and psychosocial stressors that might be contributing to the depressive symptoms. Some key points to consider:
- Lithium is approved for bipolar disorder in adults, but its efficacy in children and adolescents is limited by small sample sizes and diagnostic variability 1
- The combination of olanzapine and fluoxetine is approved for bipolar depression in adults, suggesting that adding an antidepressant to lithium may be effective for depressive symptoms 1
- Antidepressants, such as SSRIs, may be useful adjuncts for depression in patients with bipolar disorder, but caution must be taken to avoid destabilizing the patient's mood or inciting a manic episode 1
From the FDA Drug Label
ADVERSE REACTIONS ... Central Nervous System: ... psychomotor retardation, restlessness, confusion, ... Miscellaneous: Fatigue, lethargy, ...
The following adverse reactions have been reported and do not appear to be directly related to serum lithium levels ... Central Nervous System: ... psychomotor retardation, restlessness, confusion, stupor, coma, acute dystonia, ...
The patient's symptoms of depressed mood and poor motivation may be related to psychomotor retardation, a known adverse reaction of lithium, or other central nervous system effects such as fatigue and lethargy 2.
From the Research
Patient's Current Situation
The patient is currently taking lithium 750mg BID and is experiencing depressed mood and poor motivation.
Treatment Options for Bipolar Depression
- According to 3, the most commonly employed pharmacotherapies for bipolar depression include antidepressants, lithium, and anticonvulsants.
- The study 4 suggests that selective serotonin reuptake inhibitors (SSRIs) and lamotrigine have the best evidence for efficacy in treating bipolar depression.
- However, 3 also cautions that antidepressant exposure should be minimized in patients with bipolar depression due to the risk of triggering treatment-emergent mania or cycle acceleration.
Potential Risks of Lithium Therapy
- 5 reports a case of serotonin syndrome after combined treatment with lithium and fluoxetine, advising caution when treating affective disorders with combinations of serotonergic agents.
- 6 highlights the risk of lithium intoxication, particularly when taking risk medications with relative contraindications for concurrent lithium treatment.
- 7 emphasizes the importance of proper management of lithium therapy, including regular blood lithium assays, renal and thyroid monitoring, and patient information to prevent adverse effects.
Considerations for Adjusting Treatment
- 3 recommends that effective therapy should be provided as early as possible to prevent high risk of suicide and increased chronicity of symptoms.
- 4 suggests that a combination of an atypical antipsychotic and either an SSRI or lamotrigine may provide a useful first-line treatment for depressed bipolar disorder patients.
- 6 found that involving psychiatrists in the management of high lithium levels or intoxication is associated with more frequent adjustment of the maintenance lithium dose.