Thus, the medications work by allowing the body to make the best use of the reduced amounts of serotonin that it has at the time.
In due course, the levels of natural serotonin will rise again, and in some instances the SSRI can be reduced and withdrawn.
The goal in such development is to produce agents that are more efficacious, safer and better tolerated than older medications. Although all SSRI drugs have the same mechanism of action, each SSRI has slightly different pharmacological and pharmacokinetic characteristics.
This leads to differences among the SSRIs in their half-lives, clinical activity, side effects, and drug interactions.
Paroxetine and sertraline have been associated with slightly more cases of nausea.
Sexual dysfunction The SSRIs as a class produce a variety of sexual side effects, including anorgasmia, decreased libido, impotence, and delayed ejaculation.
Citalopram has been associated with loss of libido and may be associated with a relatively higher level of sexual dysfunction compared with sertraline.
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%.
The SSRIs differ in their licensed indications for non-depression disorders (which differ between countries).
Celexa (Citalopram) licensed indications: In January 2003, Prozac (fluoxetine) was approved by the FDA for the treatment of depression and OCD in children and adolescents who are 7 to 17 years of age.
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.