What are antidepressants?

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Last updated: March 12, 2025View editorial policy

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From the Guidelines

Antidepressants are a class of medications primarily used to treat depressive disorders, with second-generation antidepressants being the preferred choice due to their adverse effect profiles, cost, and patient preferences. According to the American College of Physicians guideline 1, second-generation antidepressants, such as selective serotonin reuptake inhibitors (SSRIs), serotonin-norepinephrine reuptake inhibitors (SNRIs), and atypical antidepressants, are effective for treating acute major depression.

Key Characteristics of Antidepressants

  • They work by increasing levels of neurotransmitters like serotonin, norepinephrine, and dopamine in the brain, which helps regulate mood, emotion, and behavior.
  • Common side effects include nausea, headache, sleep disturbances, and sexual dysfunction, which often improve with time.
  • The choice of antidepressant should be based on adverse effect profiles, cost, and patient preferences, as existing evidence does not justify the choice of any second-generation antidepressant over another on the basis of greater efficacy and effectiveness 1.

Monitoring and Treatment

  • Clinicians should assess patient status, therapeutic response, and adverse effects of antidepressant therapy on a regular basis beginning within 1 to 2 weeks of initiation of therapy 1.
  • Patients should be monitored for the emergence of agitation, irritability, or unusual changes in behavior, as these symptoms can indicate that the depression is getting worse.
  • Treatment should be modified if the patient does not have an adequate response to pharmacotherapy, and dosage should always be tapered under medical supervision to avoid withdrawal symptoms.

From the FDA Drug Label

Antidepressants are medicines used to treat depression and other illnesses.

Antidepressants are medicines used to treat depression and other illnesses. 2

From the Research

Definition and Types of Antidepressants

  • Antidepressants are medications used to treat depression and other mental health conditions, with selective serotonin reuptake inhibitors (SSRIs) being a commonly prescribed type 3, 4, 5, 6, 7.
  • SSRIs work by increasing the levels of serotonin in the brain, which helps to improve mood and reduce symptoms of depression 5, 6, 7.
  • Examples of SSRIs include fluoxetine, sertraline, paroxetine, fluvoxamine, and citalopram 5, 6, 7.

Mechanism of Action and Effects

  • SSRIs act by blocking the reuptake of serotonin in the presynaptic membrane, increasing the levels of serotonin in the synaptic cleft 6.
  • This increase in serotonin levels can help to improve mood, reduce anxiety, and improve sleep patterns 3, 5.
  • SSRIs have been shown to be effective in treating a range of conditions, including major depression, dysthymia, panic disorder, obsessive-compulsive disorder, and eating disorders 3, 5.

Safety and Side Effects

  • SSRIs are generally considered to be safe and well-tolerated, with a lower risk of side effects compared to older antidepressants 3, 5.
  • Common side effects of SSRIs include gastrointestinal disturbances, headache, sedation, insomnia, and sexual dysfunction 5, 7.
  • In rare cases, SSRIs can cause more serious side effects, such as serotonin syndrome, which can be life-threatening if not treated promptly 6, 7.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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