lithium + mirtazapine

Lithium + mirtazapine is a combination therapy consisting of lithium, a classic mood stabilizer, and mirtazapine, a tetracyclic antidepressant. This combination is used primarily in the management of treatment-resistant depression and bipolar depression when monotherapy with antidepressants or mood stabilizers is insufficient. Lithium acts by modulating neurotransmitter release and second messenger systems to stabilize mood, while mirtazapine enhances noradrenergic and serotonergic neurotransmission through antagonism of central presynaptic alpha-2 adrenergic inhibitory autoreceptors and heteroreceptors as well as antagonism at specific serotonin receptors (notably 5-HT2 and 5-HT3). The combination may increase the risk of serotonin syndrome due to additive serotonergic effects but has been shown in clinical studies to be generally safe with no significant pharmacokinetic interaction between the two drugs[2][4][5]. This regimen is commonly used in psychiatric practice for patients who do not respond adequately to single-agent therapy[7][8].