Boca Raton, FL, May 30, 2013 --(PR.com
)-- American Clinical Solutions is going to offer a newly designed antidepressants test panel for physicians to monitor antidepressant compliance. As usual, the test service will be available for both urine and oral fluid sample. In addition to tricyclic antidepressants (TCAs) tested on the original panel, the new panel will include six more medications and three corresponding metabolites, enabling it to cover some of most commonly prescribed antidepressants. Among them, citalopram, fluoxetine, and paroxetine belong to selective serotonin reuptake inhibitors (SSRIs), first-line therapeutic agents for treating a wide range of psychiatric disorders such as major depression, generalized anxiety disorder and post-traumatic disorder, to name but a few. SSRIs, as the name suggests, exert their effect mainly by blocking the reuptake of serotonin in neuronal synapse and increasing the level of serotonin in the synaptic cleft. Duloxetine and venlafaxine are serotonin-norepinephrine reuptake inhibitors (SNRIs), which can lead to increased concentration of both serotonin and norepinephrine in the synaptic cleft and potentiate their neuromodulatory effects. Besides treating major depression, SNRIs have also been shown effective for treating neuropathic pain and for fibromyalgia. The wide application of those medications is promoted by the advances in understanding that deficiency of major amines, namely serotonin and norepinephrine, in the human brain is responsible for common depressive disorders. Compared to TCAs, SSRIs and SNRIs exhibit more selective effects on serotonin and serotonin/norepinephrine while lacking the inhibitory effects on muscarinic, histamine H1, and alpha-adrenergic receptors; which basically means equal anti-depressive effects with a more favorable side-effect profile.
The final drug, bupropion, is an atypical antidepressant in that it does not have an inhibitory effect on serotonin reuptake and its mechanism of action is uncertain. Some recent studies suggested that bupropion works as a dopamine-uptake inhibitor, which might explain mild abuse potential of this drug. Bupropion is also a nicotinic acetylcholine receptor inhibitor and used for smoking cessation. The popularity of bupropion may be due, in part, to the fact that it does not cause sexual dysfunction and weight gain, common complaints of SSRIs. For the metabolites tested in antidepressant panel, norfluoxetine, O-desmethylvenlafaxine, and hydroxybupropion are active metabolites of fluoxetine, venlafaxine, and bupropion, respectively, formed by hepatic P450s-mediated metabolism and generally exhibit longer half-life than parent compounds. Synthetic O-desmethylvenlafaxine is also an antidepressant of its own. Fluoxetine, paroxetine, and bupropion exhibit noticeable drug-drug interactions, when co-administered with other medications, by acting as inhibitors of hepatic P450s activities, especially CYP2D6 activity. Plasma levels of several pain medications such as oxycodone, hydrocodone, and tramadol might be increased when co-administered with antidepressants.
Cheng Fang, MD., PH D., DABT | email@example.com
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