Selective serotonin reuptake inhibitors immediate

SSRI selective serotonin reuptake inhibitor (class of drugs used to treat depression, e.g., sertraline) SSS sick sinus syndrome stat immediately (Latin statim ) supl supplement or supplied supp suppository Susp suspension... 

Paroxetine is a selective serotonin reuptake inhibitor that blocks reuptake of serotonin, enhancing serotonergic function. It is used to treat panic disorder or social anxiety disorder (except Pexeva), as defined in the DSM-IV major depressive disorder, as defined in DSM-111 (immediate release) orDSM-lV (controlled release). Immediate release only for obsessive-compulsive disorder (OCD) generalized anxiety disorder (GAD) (except Pexeva) posttraumatic stress disorder (PTSD), as defined in the DSM-IV (except Pexeva). 

One of the major drawbacks in the pharmacotherapy of depression has been the delay in response of 2-4 weeks between administering an antidepressive drug and the resolution of depression, despite immediate uptake blockade/reduced metabolism of monoamines at a synaptic level. The 5-HTia receptors are a subgroup of G-protein-coupled serotonergic receptors that are present postsynaptically on the soma and dendrites of serotonergic neurons. These receptors are found mainly in the mid and dorsal raphe nuclei of the midbrain and their main effect is inhibitory in nature. It has been demonstrated (mainly in rats) that repeated administration of selective serotonin reuptake inhibitors (SSRIs) and other antidepressants leads to functional desensitization of the somatodendritic 5-HTia... 

Selective serotonin reuptake inhibitors (SSRIs) are effective antidepressants with fewer side effects than the older tricyclics. However, SSRIs require weeks of treatment before efficacy is observed. This delay in efficacy is believed to be due to stimulation of inhibitory 5-HT1A autoreceptors the onset of antidepressant activity is consistent with a time-dependent desensitization of 5-HT1A autoreceptors. Combining SSRI and 5-HT1A receptor antagonism within one molecule should maximize serotonergic function and result in an immediate increase in synaptic levels of 5-HT in forebrain... 

Venlafaxine is a serotonin and noradrenaline reuptake inhibitor (SNRI). It shares these properties with the TCAs amitriptyhne, clomipramine and imip-ramine, but it is the first selective SNRI, with low affinity for muscarinic, histaminic and a-adrenergic receptors. At low doses serotonergic effects predominate, but at higher doses the reuptake of noradrenaline is significantly blocked (Melichar et al. 2001). It is available as immediate and extended release (XR) preparations. 

FIGURE 6-36. Mechanism of action of serotonin selective reuptake inhibitors (SSRls)—part 2. When an SSRI is administered, it immediately blocks the serotonin reuptake pump (see icon of an SSRI drug capsule blocking the reuptake pump). However, this causes serotonin to increase initially only in the somatodendritic area of the serotonin neuron (left) and not in the axon terminals (right). 

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