Mianserin is a synthetic tetracyclic antidepressant compound (C₁₈H₂₀N₂, CAS 24219-97-2) used primarily in the treatment of depression, particularly for individuals who may not respond well to other antidepressant medications. It acts by antagonizing certain serotonin and histamine receptors. It is effective in alleviating symptoms such as low mood, anxiety, and sleep disturbances. Due to its sedative properties, it is often prescribed for patients experiencing insomnia or agitation associated with depression. Additionally, mianserin is sometimes used off-label to manage chronic pain conditions, such as neuropathic pain, due to its ability to modulate certain neurotransmitters. It is also considered a suitable option for elderly patients or those with cardiovascular concerns, as it has a relatively favorable side effect profile compared to some other antidepressants. As a reagent, it is supplied as a white solid with high purity for pharmaceutical research or synthesis.