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Selective Serotonin Reuptake Inhibitors (Clomipramine, Fluoxetine) (view source)
Revision as of 12:42, 12 September 2014
, 12:42, 12 September 2014→Mechanism of Action
===Selective serotonin reuptake inhibitors (SSRIs)===
===Selective serotonin reuptake inhibitors (SSRIs)===
SSRIs are a group of drugs that all have a greater effect on serotonin reuptake than noradrenaline reuptake. Unlike TCAs, which are named on the basis of chemical structure, the SSRIs are named according to their primary effect on serotonin reuptake. The ratio of serotonin reuptake selectivity in favour varies from around 15:1 (fluoxetine) to more than 150:1 (sertraline). Along with increasing serotonergic selectivity, SSRI drugs also show fewer effects on other neurotransmitter systems. In particular, they are less anticholinergic than TCAs.
SSRIs are a group of drugs that all have a greater effect on serotonin reuptake than noradrenaline reuptake. Unlike TCAs, which are named on the basis of chemical structure, the SSRIs are named according to their primary effect on serotonin reuptake. The ratio of serotonin reuptake selectivity in favour varies from around 15:1 (fluoxetine) to more than 150:1 (sertraline). Along with increasing serotonergic selectivity, SSRI drugs also show fewer effects on other neurotransmitter systems. In particular, they are less anticholinergic than TCAs.
===Effects on Anxiety and Panic===
Panic is a specific manifestation of anxiety and the mechanism of action of drugs that reduce panic share a common factor. Only drugs that reduce the firing rate of neurons in the Locus Coeruleus (LC) effectively reduce panic.
Numerous models of anxiety have been tested in animals. Many are not apparently reliable detectors of anxiolytic effect, and have not been applied to more modern anxiolytic/antidepressant drugs like SSRIs/SRIs. Those in which there is a response to TCA/SRI and SSRI drugs include:
*Approach-avoidance conflict (Stretched approach posture test).
*Separation distress vocalisation (guinea pig isolation calls, rat pup isolation ultrasonic vocalisation).
*Defensive burying in rodents (only some 5-HT reuptake inhibitors)
Interestingly no effect has been found in those tests (so far performed) that involve conditioned fear potentiated startle responses.
==Adverse Effects<ref>Wiersma, J., Honig, A. & Peters, F. P. J. (2000). Clomipramine-induced allergic hepatitis: a case report. International Journal of Psychiatry in Clinical Practice 4, 69–71.</ref>==
==Adverse Effects<ref>Wiersma, J., Honig, A. & Peters, F. P. J. (2000). Clomipramine-induced allergic hepatitis: a case report. International Journal of Psychiatry in Clinical Practice 4, 69–71.</ref>==