Is Ativan (lorazepam) a selective serotonin reuptake inhibitor (SSRI)?

Ativan (Lorazepam) is NOT an SSRI

Ativan (lorazepam) is a benzodiazepine anxiolytic medication, not a selective serotonin reuptake inhibitor (SSRI). 1

Classification and Mechanism of Action

Lorazepam (Ativan) belongs to the benzodiazepine class of medications, which work through a completely different mechanism than SSRIs:

• Benzodiazepines (including Ativan):

  • Act by enhancing the effect of gamma-aminobutyric acid (GABA), the main inhibitory neurotransmitter in the brain
  • Produce anxiolytic, sedative, hypnotic, anticonvulsant, and muscle relaxant effects
  • Classified as anxiolytic drugs 1

• SSRIs (examples include fluoxetine, paroxetine, sertraline, citalopram, escitalopram):

  • Inhibit the presynaptic reuptake of serotonin in the brain
  • Increase availability of serotonin at the synaptic cleft
  • Lead to downregulation of inhibitory serotonin autoreceptors
  • Eventually heighten serotonergic neuronal firing rate 1

Clinical Uses of Ativan (Lorazepam)

Ativan is primarily used for:

• Management of insomnia
• Anxiety
• Agitation 1
• Acute control of seizures
• Preoperative sedation

Distinguishing Features and Risks

The distinction between benzodiazepines and SSRIs is important for several reasons:

1. Different side effect profiles:

   • Benzodiazepines like Ativan can cause tolerance, addiction, depression, and cognitive impairment 1
   • Approximately 10% of patients may experience paradoxical agitation with benzodiazepines 1

2. Different risk classifications:

   • According to cardiovascular risk classification, benzodiazepines like lorazepam are generally considered Class A drugs (without risk of QT prolongation or Torsades de Pointes) 1
   • Some SSRIs, by contrast, carry risks of QT prolongation 1

3. Different drug interactions:

   • Benzodiazepines have different drug interaction profiles than SSRIs
   • SSRIs can interact with MAOIs causing serotonin syndrome, while benzodiazepines do not 2

Clinical Implications

Understanding that Ativan is a benzodiazepine and not an SSRI has important clinical implications:

• Addiction potential: Regular use of benzodiazepines like Ativan can lead to tolerance and addiction, unlike SSRIs 1
• Withdrawal concerns: Benzodiazepines require careful tapering to avoid withdrawal symptoms
• Duration of therapy: Benzodiazepines are generally recommended for short-term use, while SSRIs are often used for longer-term management of depression and anxiety disorders

Common Misconception

The confusion between Ativan and SSRIs may arise because both medication classes can be used to treat anxiety disorders, though they work through entirely different mechanisms and have different indications, side effect profiles, and risk considerations.