What is the common Selective Serotonin Reuptake Inhibitor (SSRI)?

From the Guidelines

Common SSRIs include fluoxetine (Prozac), sertraline (Zoloft), escitalopram (Lexapro), paroxetine (Paxil), and citalopram (Celexa), with sertraline often considered the most widely prescribed due to its favorable side effect profile and efficacy across multiple conditions. When considering the treatment of anxiety disorders, the choice of a specific SSRI is governed by considerations such as pharmacokinetics, pharmacodynamics, tolerability, cost, insurance formularies, and unique risks leading to warnings or precautions 1. The SSRI medication class is a group of chemically and pharmacologically different compounds that inhibit the presynaptic reuptake of serotonin in the brain, thereby increasing availability of serotonin at the synaptic cleft, which is believed to lead to a downregulation of inhibitory serotonin autoreceptors, heightening the serotonergic neuronal firing rate, and increasing serotonin release 1. Some key points to consider when prescribing SSRIs include:

• Typical starting doses range from 25-50mg daily for sertraline, with gradual increases as needed up to 200mg daily
• SSRIs generally take 4-6 weeks to reach full therapeutic effect, though some improvement may be noticed earlier
• Common side effects include nausea, headache, sleep disturbances, and sexual dysfunction, which often improve with time
• It's essential to take SSRIs consistently at the same time each day and not to stop them abruptly, as this can cause withdrawal symptoms
• A gradual tapering schedule under medical supervision is recommended when discontinuing these medications
• The best-fitting model for SSRI response may be a logarithmic model demonstrating statistically significant improvement in anxiety symptoms within 2 weeks of treatment initiation, clinically significant improvement by week 6, and maximal improvement by week 12 or later 1. Medications from the SSRI class currently marketed in the United States are citalopram, escitalopram, fluoxetine, fluvoxamine, paroxetine, sertraline, and vilazodone, with the primary mechanism deemed sufficiently similar across individual medications to warrant extension of the findings to the medication class 1. However, it is crucial to note that all of the SSRIs have a boxed warning for suicidal thinking and behavior through age 24 years, and close monitoring for suicidality is recommended by the FDA, especially in the first months of treatment and following dosage adjustments 1. In terms of specific considerations, sertraline may require twice-daily dosing at low doses, and fluvoxamine may require twice-daily dosing at any dose, due to their pharmacokinetic profiles 1. Ultimately, the choice of SSRI should be individualized based on the patient's specific needs and circumstances, taking into account factors such as efficacy, tolerability, and potential interactions with other medications 1.

From the FDA Drug Label

The mechanism of antidepressant action of escitalopram, the S-enantiomer of racemic citalopram, is presumed to be linked to potentiation of serotonergic activity in the central nervous system (CNS) resulting from its inhibition of CNS neuronal reuptake of serotonin (5-HT). Escitalopram is a highly selective serotonin reuptake inhibitor (SSRI) with minimal effects on norepinephrine and dopamine neuronal reuptake. Fluvoxamine maleate is a selective serotonin (5-HT) reuptake inhibitor (SSRI) belonging to a new chemical series, the 2-aminoethyl oxime ethers of aralkylketones. Sertraline hydrochloride is a selective serotonin reuptake inhibitor (SSRI) for oral administration.

The common SSRI mentioned in the drug labels are:

• Escitalopram 2
• Fluvoxamine 3
• Sertraline 4

From the Research

Common SSRIs

• The most commonly prescribed SSRIs include:
  • Paroxetine 5, 6, 7, 8, 9
  • Sertraline 5, 6, 7, 8, 9
  • Fluvoxamine 5, 6, 7, 9
  • Citalopram 7, 8, 9
  • Fluoxetine 6, 7, 8, 9
  • Escitalopram 6, 8

Characteristics of Common SSRIs

• Paroxetine, sertraline, and fluvoxamine have shorter elimination half-lives and are metabolized to clinically inactive compounds 5
• Sertraline and paroxetine are effective for a wide range of indications, including depression, anxiety, and obsessive-compulsive disorder 5, 6, 8
• Citalopram and sertraline have a lower theoretical risk of drug interactions due to their pharmacokinetic profiles 9

Efficacy and Tolerability

• SSRIs have been shown to be effective in treating depression, anxiety, and other disorders, with similar efficacy among different SSRIs 6, 7, 8
• However, tolerability can vary among SSRIs, with some having a higher risk of adverse effects or discontinuation reactions 5, 6, 9