Monoamine oxidase with SSRIs

Drugs that may interact with linezolid include monoamine oxidase inhibitors, SSRIs, and adrenergic agents (eg, dopamine, epinephrine). 

Treatment of Major Depression. Dmgs commonly used for the treatment of depressive disorders can be classified heuristicaHy iato two main categories first-generation antidepressants with the tricycHc antidepressants (TCAs) and the irreversible, nonselective monoamine—oxidase (MAO) inhibitors, and second-generation antidepressants with the atypical antidepressants, the reversible inhibitors of monoamine—oxidase A (RIMAs), and the selective serotonin reuptake inhibitors (SSRIs). Table 4 fists the available antidepressants. 

MDMA overdose as well as the concomitant consumption of selective serotonin reuptake inhibitors (SSRI) with other dmgs that exert serotoninergic effects (such as inhibitors of monoamine oxidase) can rapidly lead to the serotonin syndrome. Its symptoms, which are reversible upon cessation, of the drug include confusion, muscle rigidity in the lower limbs, and hyperthermia suggesting an acute reaction to serotonin overflow in the CNS. Blocking the function of SERT outside the brain causes side effects (e.g., nausea), which may be due to elevated 5HT however , impairment of transporter function is not equivalent to direct activation of 5HT recqrtors in causing adverse effects such as fibrosis and pulmonary hypertension. 

Several different types of serotonin receptor (for example, S-HTi / 5-HT2A/ 5-HT2C/ 5-HTib/id) have been associated with the motor side effects of the SSRIs which may arise should these drugs be administered in conjunction with a monoamine oxidase inhibitor. The 5-HT3 receptor is an example of a non-selective cation charmel receptor which is permeable to both sodium and potassium ions and, because both calcium and magnesium ions can modulate its activity, the 5-HT3 receptor resembles the glutamate-NMDA receptor. Antagonists of the 5-HT3 receptor, such as ondansetron, are effective antiemetics and are particularly useful when... 

Hypersensitivity to SSRIs in combination with a monoamine oxidase inhibitor (MAOl), or within 14 days of discontinuing an MAOl administration of thioridazine with fluoxetine or within a minimum of 5 weeks after fluoxetine has been discontinued coadministration of fluvoxamine with cisapride, thioridazine or pimozide concomitant use of thioridazine with paroxetine concomitant use of pimozide with sertraline coadministration of sertraline oral concentrate and disulfiram. 

Serious toxic reactions with delirium can arise when specific serotonin reuptake inhibitors (SSRIs) are taken with other drugs that increase central and peripheral serotonergic activity. Known as the serotonin syndrome , this reaction consists of excitation, restlessness, fluctuations in consciousness, with tremor, rigidity, myoclonus, sweating, flushing, pyrexia, cardiovascular changes, and rarely coma and death (Sternbach, 1991). The syndrome has occurred when SSRIs have been combined with irreversible monoamine oxidase... 

Dmg-induced serotonin syndrome is generally mild and resolves when the offending drugs are stopped. However, it can be severe and deaths have occurred. A large number of drugs have been implicated including tricyclic antidepressants, monoamine oxidase inhibitors (MAOIs), selective serotonin re-uptake inhibitors (SSRIs), pethidine, lithium, and dextromethorphan. The most severe type of reaction has occurred with the combination of selective serotonin re-uptake inhibitors and monoamine oxidase inhibitors. Both non-selective MAOIs such as phenelzine and selective MAOIs such as moclobemide and selegiline have been implicated. 

With the introduction of the SSRIs, the safety and tolerability of antidepressants improved remarkably. As a class, these medications have little or no affinity for cholinergic, (3-adrenergic or histamine receptors and do not interfere with cardiac conduction. They are well tolerated by patients with heart disease and by the elderly, who are especially sensitive to the anticholinergic and orthostatic effects of the tricyclic antidepressant agents (TCAs) and monoamine oxidase inhibitors (MAOIs). 

Most child and adolescent studies published thus far have focused on the effects of the tricyclic antidepressants (TCAs) and, more recently, the SSRIs. A few open studies have also shown that monoamine oxidase inhibitors (MAOIs) can be used safely with children and adolescents (Ryan et ah, 1988b), but noncompliance with dietary requirements may present a significant problem for minors. Other antidepressants, including the heterocyclics (HTC) (e.g., amoxapine, maprotiline), buproprion, venlafaxine, and nefazodone, have been found to be efficacious for the treatment of depressed adults (APA, 2000), but they have not been well studied for the treatment of MDD in children and adolescents. Therefore, this chapter mainly describes the use of SSRIs and TCAs for youth with MDD. 

In contrast, a less extensive but still convincing database has identified important clinical differences in efficacy for antidepressants used to treat patients with atypical or comorbid depression. Individuals with atypical depression (distinct quality of mood, hyperphagia, hypersomnia, psychomotor retardation, rejection sensitivity, and such unusual atypical features as chocolate craving] have superior responses to monoamine oxidase inhibitors (MAOIs], selective serotonin reuptake inhibitors (SSRIs), and perhaps venlafaxine, and most do not respond well to tricyclic antidepressants (TCAs] (Davidson et al. 1982 Liebowitz et al. 1988 Quitkin et al. 1988, 1991). Despite these data, TCAs unfortunately have been the first choice for most atypical patients until SSRIs were introduced. 

A growing number of drugs are used that affect the many neurotransmitters in the brain benzodiazepines and others act on GABAergic transmission antidepressants, such as monoamine oxidase inhibitors and tricyclic antidepressants, are thought to increase the concentration of transmitter amines in the brain and so elevate mood—these will also act at peripheral nerve terminals, so interactions with them are a combination of peripheral and central actions. Levodopa (L-dopa) increases central as well as peripheral dopamine, and the newer class of psychoactive drugs, the selective serotonin reuptake inhibitors (SSRIs) of which the ubiquitous fluoxetine (Prozac) is best known, act in a similar way on serotonergic pathways. 

Monoamine oxidase inhibitors (eg, tranylcypromine, phenelzine) are older antidepressants that are occasionally used for resistant depression. They can cause severe hypertensive reactions when interacting foods or drugs are taken (see Chapters 9 and 30), and they can interact with the selective serotonin reuptake inhibitors (SSRIs). 

Newer antidepressants (eg, fluoxetine, paroxetine, citalopram, venlafaxine) are mostly SSRIs and are generally safer than the tricyclic antidepressants and monoamine oxidase inhibitors, although they can cause seizures. Bupropion (not an SSRI) has caused seizures even in therapeutic doses. Some antidepressants have been associated with QT prolongation and torsade de pointes arrhythmia. SSRIs may interact with each other or especially with monoamine oxidase inhibitors to cause the serotonin syndrome, characterized by agitation, muscle hyperactivity, and hyperthermia (see Chapter 16). 

Antidepressants were first introduced into the market in the 1950s with the serendipitous discovery of the antidepressant effect of two drugs initially evaluated for other medical uses Iproniazide, a monoamine oxidase inhibitor (MAOI), and Imipramine, a tricyclic antidepressant (TCA). Since then, a whole new generation of chemically and pharmacologically unrelated compounds have been introduced, which appear to be safer and better tolerated due to a more specific mechanism of action. These include selective serotonin reuptake inhibitors (SSRIs), serotonin and... 

Discontinuing selective serotonin reuptake inhibitors (SSRIs) may induce a syndrome wherein the main neuropsychiatric symptoms are dizziness, shock-like sensations, anxiety, irritability, agitation, and insomnia. These symptoms usually develop 1 to 7 days after abrupt or gradual discontinuation. Antidepressant discontinuation may also induce mania, mainly reported with tricyclics and monoamine oxidase inhibitors but also observed with SSRIs. 

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