Panic disorder mirtazapine

Taken together, the efficacy of antidepressants covers the spectrum of anxiety disorders, although there are important differences between drugs in the group (Table 3). Several new antidepressants have been marketed since the SS-RIs venlafaxine and mirtazapine are discussed later (Sects. 3.2.1.2 and 3.2.1.4) nefazodone, a serotonin reuptake inhibitor and postsynaptic 5-HT2 blocker showed promise in early studies but was recently withdrawn by its manufacturers reboxetine, a noradrenaline reuptake inhibitor (NARI) showed benefits in panic disorder in one published study (Versiani et al. 2002) and further evidence of its anxiolytic efficacy is awaited. 

Mirtazapine (Panic disorder, PTSD) Few side-effects on initiation few long-term side-effects Relatively safe in overdose Not reported... 

In addition to its efficacy as a first-line antidepressant, mirtazapine may have enhanced efficacy due to its dual mechanism of action (Fig. 7—3), especially in combination with other antidepressants that block serotonin and/or norepinephrine reuptake. This will be discussed below in the section on antidepressant combinations. Mirtazapine may also have utility in panic disorder, generalized anxiety disorder, and other anxiety disorders, but has not been intensively studied for these indications. 

Newer antidepressants. Although the SSRIs are the only antidepressants formally approved for the treatment of panic disorder, recent evidence suggests that several other antidepressants are promising treatments for panic disorder as well. These include nefazodone, venlafaxine XR, mirtazapine, and reboxetine. Bupropion, however, does not seem to have apparent antipanic actions. Since the documentation of efficacy of these newer antidepressants in panic disorder is still emerging, they tend to be used as second-line therapy after SSRIs foil to improve panic or in patients who cannot tolerate them. 

FIGURE 9-6. Various treatments can be given in combination for panic disorder (i.e., panic combos). The basis of all many combination treatments is a serotonin selective reuptake inhibitor (SSRI). Other antidepressants such as venlafaxine, nefazodone, mirtazapine, tricyclic antidepressants, and monoamine oxidase inhibitors can all have antipanic actions, although they are second-line treatments, as are the benzodiazepines. On the other hand, benzodiazepines are often added to SSRIs, particularly at the initiation of an SSRI and intermittently when there is breakthrough panic. Cognitive and behavioral psychotherapies can also be added to any of these drug treatments. 

Novel antidepressants Given the importance of SSRIs in the treatment of panic disorder, other, newer antidepressants are developing an efficacy portfolio for panic disorder (and other anxiety disorders) as well. Thus, venlafaxine XR, nefazodone, and mirtazapine hold promise for the treatment of panic disorder. One early study also suggests that the new antidepressant reboxetine may be effective in panic disorder. 

HT2 antagonists appear to have efficacy in GAD but not panic disorder (which then may exacerbate). No 5-HT2 antagonists are marketed for anxiety disorders but antidepressants with 5-HT2 antagonism include trazodone, mirtazapine and nefazodone. 

When compared with the selective serotonin reuptake inhibitors (SSRIs), mirtazapine may show an earlier onset of action (although data are currently not well established). Mirtazapine has also been found to be efficacious in the treatment of elderly patients with depression. Mirtazapine has been shown to be effective in the treatment of panic disorder, social phobia, and post-traumatic stress disorder. In one study, mirtazapine combined with citalopram in obsessive-compulsive patients induced an earlier response when compared with citalopram plus placebo. It was suggested that antagonism of presynaptic a2-adrenergic receptors does not enhance serotonin neurotransmission directly, but rather disinhibits the norepinephrine activation of serotonergic neurons and thereby increases serotonergic neurotransmission by a mechanism that may not require a time-dependent desensitization of receptors. 

Sarchiapone M, Amore M, De Risio et al. Mirtazapine in the treatment of panic disorder an open-label trial. Int Clin Psychopharmacol 2003 18 35-38. 

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