SSRIs

SSRIs, or selective serotonin reuptake inhibitors, are a class of antidepressant drugs that selectively inhibit the serotonin transporter (SERT). By blocking serotonin reuptake, they raise serotonin levels in the synaptic cleft, reinforcing serotonin signaling. They are generally preferred over older antidepressants due to a more favorable side-effect profile and safer overdose risk.

Commonly prescribed for major depressive disorder and a range of anxiety disorders, including generalized anxiety disorder, social anxiety disorder, panic disorder, and obsessive‑compulsive disorder. They are also used for post-traumatic stress disorder and premenstrual dysphoric disorder and may be prescribed off-label for other conditions such as chronic pain or eating disorders.

Onset of symptom relief typically takes several weeks. Common adverse effects include nausea, insomnia or sleep disturbance, sexual dysfunction, and weight changes. Some individuals may experience increased anxiety early in treatment. SSRIs can interact with other serotonergic drugs to cause serotonin syndrome and may increase bleeding risk with NSAIDs or anticoagulants. Discontinuing abruptly can cause withdrawal symptoms; gradual taper is recommended.

Medications in this class include fluoxetine, sertraline, citalopram, escitalopram, paroxetine, and fluvoxamine. Fluoxetine has a long half-life, which can ease withdrawal but complicate switching; others vary in half-life and potency, influencing dosing and side effects.

Use in pregnancy is guided by risk-benefit considerations; most SSRIs are considered relatively safe when benefits outweigh risks, with potential neonatal adaptation syndrome after birth. In children and adolescents, fluoxetine is approved for major depressive disorder and OCD; all SSRIs require monitoring for suicidality and behavioral changes.