Each antidepressant produces approximately a 60% overall response rate (ie, at least a 50% reduction in symptoms as a result of treatment).
However, SSRIs differ in their potency and selectivity in inhibiting serotonin reuptake and many of them have important effects on other transporters and receptors.
Each SSRI has a unique profile of multiple pharmacologic actions, which explains the differences in their efficacy and tolerabilitythe most potent serotonin reuptake blocker, but has a low selectivity for the serotonin reuptake muscarinic cholinergic receptors (most potent blocker of muscarinic receptors among the SSRIs) histamine H1 receptors nitric oxide synthase cytochrome P450 2D6 the second most potent inhibitor of serotonin reuptake and the second most selective blocker of serotonin over noradrenaline uptake dopamine reuptake (more potent dopamine uptake inhibitor than other SSRIs) All the SSRIs are licensed for major depressive disorder and are considered to be the first-line treatments of depression.
The SSRIs are reported to cause sexual dysfunction in the following descending order of frequency: citalopram 72.7%; paroxetine 70.7%; sertraline 62.9%; fluvoxamine 62.3%; fluoxetine 57.7%.
Weight gain Weight gain is another troubling side effect. Paroxetine, fluoxetine, citalopram and sertraline have been shown to increase body weight after 612 months of therapy.
SSRIs seem to relieve symptoms of depression by blocking the reabsorption (reuptake) of serotonin by certain nerve cells in the brain.
This leaves more serotonin available, which enhances neurotransmission and improves mood.
Celexa is manufactured by Forest Pharmaceuticals, Inc.
Lexapro (Escitalopram oxalate) is the newest and most selective of the SSRIs approved by the FDA in August 14, 2002. The brain communicates with itself through the use of special chemicals called neurotransmitters, such as serotonin and norepinephrine.
Sexual dysfunction The SSRIs as a class produce a variety of sexual side effects, including anorgasmia, decreased libido, impotence, and delayed ejaculation.
Analysis of the clinical trials suggests that fluvoxamine and fluoxetine are less likely to produce sexual side effects than paroxetine and sertraline.
In due course, the levels of natural serotonin will rise again, and in some instances the SSRI can be reduced and withdrawn.