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12 Cards in this Set
- Front
- Back
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What is the prototypical dual serotonin-norepinephrine reuptake inhibitor (SNRI)? What makes it different from a TCA, which also blocks 5HT and NE reuptake?
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Venlafaxine is the prototypical SNRI, a class of drugs that are SELECTIVE for 5HT and NE reuptake blockade without alpha 1, cholinergic, or histamine receptor blocking properties
Stahl 246 |
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What other NT levels are modulated by Venlafaxine and what are the relative levels dosages/potencies?
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Venlafaxine also blocks DA reuptake. The greater the potency, the lower the dose at which inhibition is present. Potency is high for 5HT, moderate for NE, and low for DA.
Stahl 246-7 |
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What measure has increased toleration of venlafaxine and what is the therapeutic significance?
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Venlafaxine XR. Decreases side effects, especially nausea; this is important considering the trend in psychiatry to use it at high doses in order to exploit both the 5HT and NE mechanisms
Stahl 247 |
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Name a dual reuptake inhibitor (SNRI) that is used for fibromyalgia, but not MDD
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Milnacipran (Savella)
Stahl 247, Wiki |
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Name an analgesic that also has selective 5HT/NE reuptake inhibition
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Tramadol (Ultram)
Stahl 247 |
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Name a selective SNRI that is approved for use in MDD, GAD, fibromyalgia and neuropathy
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Duloxetine (Cymbalta)
Stahl 247, Wiki |
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Why might the dual blockade approach of an SNRI be better than an older, classical SSRI? And in which patients is this most likely/necessary?
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These dual SNRIs are "cleaner" than the "dirtier" SSRIs (have less of the alpha 1, cholinergic, or histamine receptor blocking actions), may exhibit synergy. They are often more efficacious at higher doses (unlike other antidepressants, whose efficacy changes little at high doses) seemingly because additional mechanisms become active at those higher doses.
Stahl 249 |
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To what class of drugs does Mirtazapine belong and how does it work? What four other receptors does it block?
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Antidepressant that works as an alpha-2 receptor antagonist. It blocks NE binding to both presynaptic heteroreceptors on 5HT neurons and presynaptic autoreceptors on NE neurons; in both cases it "cuts the brake cable" allowing the NTs to be released by blocking inhibition/negative feedback. It also blocks 5HT2A/C/3 and H1 receptors
Stahl 251 |
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How does alpha 2 receptor blockade both "cut the brakes" and "press the accelerator" for serotonin release?
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Alpha 2 receptor blockade (i.e. via Mirtazapine) increases NE levels. Since NE neurons from the locus ceruleus innervate the 5HT neurons in the midbrain raphe, more NE stimulates postsynaptic alpha-1 receptors, provoking 5HT release.
Stahl 251-2 |
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What effects does Mirtazapine have on 5HT receptors in general?
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When presynaptic alpha 2 heteroreceptors
are blocked, 5HT is released, but it is directed to the 5HT1A receptor because 5HT actions at 5HT2A, 5HT2C, and 5HT3 receptors are blocked. The result is that antidepressant and anxiolytic actions are preserved but the side effects associated with stimulating 5HT2A, 5HT2C, and 5HT3 receptors are blocked. However, sedation and weight gain may result from these actions. Stahl 255 |
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What are the specific effects of Mirtazapine on each 5HT receptor?
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5HT1 - more 5HT binding. anxiolytic. antidepressant
5HT2A - 5HT blocked. Anxiolytic, less sleep/sexual dysfunction (sedation as well) 5HT2C - 5HT blocked. anxiolytic. weight gain 5HT3 - 5HT blocked. no GI problems/nausea Stahl 255 |
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What are Mirtazapine's actions on H1 receptors?
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It blocks H1 receptors, acting as an anxiolytic, and causing weight gain and sedation.
Stahl 256 |
