Mirtazapine toxicity

The clinician should bear in mind the toxic potential for the various antidepressant medications when patients already have or develop suicidality. The TCAs and MAOIs have narrow therapeutic indices, whereas the SSRIs, SNRIs, nefa-zodone, and mirtazapine have wide therapeutic indices.22... 

A controlled trial of duloxetine (Cymbalta)—like venlafaxine a dual serotonin-norepinephrine reuptake inhibitor—in the treatment of GAD is currently underway. Anecdotal data suggests that nefazodone (Serzone) and mirtazapine (Remeron) may be effective in the treatment of GAD, though no controlled data is available. In addition, recent concerns regarding nefazodone and liver toxicity have limited this medication s utility. Please refer to Chapter 3 for more information regarding these antidepressants. 

Data on the consequences of overdose of other new antidepressant agents are limited, but current evidence suggests that reboxetine and mirtazapine have low toxicity in overdose (Buckley 539). Reboxetine, as would be expected, presents with signs of noradrenergic overactivity, such as sweating, tachycardia, hypertension, and anxiety. The characteristic feature of mirtazapine overdose is sedation (Buckley 539). 

Overall the current data suggest that the safety advantage in overdose relative to tricyclic antidepressants enjoyed by SSRIs may extend to reboxetine and mirtazapine. Amfebutamone and venlafaxine are more toxic than SSRIs in overdose, but they are still likely to be safer than tricyclic antidepressants. 

MAOIs MIRTAZAPINE Risk of severe hypertensive reactions and of serotonin syndrome > For signs and symptoms of serotonin toxicity, see Clinical Features of Some Adverse Drug Interactions, Serotonin toxicity and serotonin syndrome Additive inhibition of both serotonin and norepinephrine reuptake Avoid co-administration. MAOIs should not be started for at least 2 weeks after stopping mirtazapine (moclobemide can be started at least 1 week after stopping mirtazapine). Conversely, mirtazapine should not be started for at least 2 weeks after stopping MAOIs... 

CANNABIS MIRTAZAPINE i levels, with risk of therapeutic failure Induction of CYP1 A2-mediated metabolism by any form of smoking. Foods (e.g. broccoli, cabbage, Brussels sprouts, chargrilled meat) also induce this isoenzyme Watch for poor response to mirtazapine conversely, watch for toxic effects if a previously heavy cannabis user stops smoking... 

Many noncyclic antidepressants are now available, including trazodone (Desyrel l), nefazodone (Serzone ), fluoxetine (Prozac ), sertraline (Zolotf ), citalopram (Celexa ), escitalopram (Lexapro ), paroxetine (Paxil ), tluvoxamine (Luvox ), venlafaxine (Effexor ), and bupropion (Wellbutrin ). Bupropion is also marketed under the brand name Zyban tor smoking cessation. Mirtazapine (Remeron ), a tetracyclic antidepressant, has recently become available. In general, these drugs are much less toxic than the tricyclic antidepressants (see p 90) and the monoamine oxidase (MAO) inhibitors (p 269), although serious effects such as seizures and hypotension occasionally occur. Noncyclic and tricyclic antidepressants are described in Table 11-7. 

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