Antidepressiva

Antidepressants are medicines used to treat depressive disorders and several related conditions characterized by low mood, reduced energy, and anhedonia. They modulate brain monoamines such as serotonin, norepinephrine, and dopamine and are also used for anxiety disorders, chronic pain, obsessive-compulsive disorder, and sleep problems.

Major classes include selective serotonin reuptake inhibitors (SSRIs) like fluoxetine, sertraline, and escitalopram; serotonin-norepinephrine reuptake inhibitors (SNRIs) such as venlafaxine and duloxetine; tricyclic antidepressants (TCAs) such as amitriptyline; monoamine oxidase inhibitors (MAOIs) such as phenelzine; and atypical agents such as bupropion, mirtazapine, and trazodone.

Most antidepressants work by increasing synaptic monoamines, though mechanisms differ by class. SSRIs block serotonin reuptake; SNRIs block serotonin and norepinephrine reuptake; TCAs affect multiple transporters and receptors; MAOIs inhibit monoamine breakdown. Therapeutic effects typically appear after two to six weeks with continued treatment.

Effectiveness varies among individuals. They can reduce depressive symptoms and relapse risk, but full remission may take time. They are also used for some anxiety disorders, chronic pain, and sleep disturbances, sometimes in combination with psychotherapy.

Safety and monitoring: Common side effects include nausea, sleep disturbance, dry mouth, sexual dysfunction, and weight change. Elderly patients may risk hyponatremia; abrupt stopping can cause withdrawal symptoms. Interactions with other serotonergic or stimulant drugs can cause serotonin syndrome. Bipolar disorder requires mood stabilization to avoid mania; MAOIs require dietary and drug restrictions.

Clinical use: Initiation involves starting at a low dose and gradually increasing while monitoring response and adverse effects. Treatments typically last after remission for several months, with longer courses considered for relapse prevention. Choice depends on history, comorbidities, and patient preferences.