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Antidepressant and Anti Anxiety MedicationsAntidepressants work primarily by altering levels of brain chemicals called neurotransmitters. The most important of these are serotonin, norepinephrine, and dopamine. Neurotransmitters enable the neurons (brain cells) to communicate with each other. What is the best and most effective antidepressant? In general, antidepressants alone help about 60%-70% of those taking them. All of the antidepressants have been shown to work. Unfortunately, they don't work for everybody, and finding the right one is something of an experiment - trying to match the chemistry of the antidepressant with the person's unique body chemistry. Sertraline and escitalopram are the best of 12 new-generation antidepressants in terms of efficacy and acceptability, according to the recent analysis published in The Lancet1. Mirtzapine and venlafaxine are also very effective. However, patients are more likely to quit taking them because of side effects. It is important to note that these findings are not true for all people. Selective serotonin reuptake inhibitors (SSRIs)
Prior to the introduction of the first SSRI in 1987, the treatment of depression was limited to the tricyclic antidepressants (TCAs) and the monoamine oxidase inhibitors (MAOIs). Although SSRIs have not been surpassed in their efficacy, remarkable advances have been achieved in safety. SSRIs alter the balance of neurotransmitter serotonin (5-hydroxytryptamine) - one of the chemicals used to pass neuron signals in the brain. They prevent the reuptake (absorption) of serotonin back into the nerve cells which helps to lift the mood. Because of their selectivity for neuronal uptake of serotonin, the diverse unwanted effects peculiar to tricyclics (anticholinergic, cardiotoxicity) are absent with SSRIs. They are devoid of significant affinity for alpha1-adrenergic, H1-histamine, and muscarinic receptors. Today Selective Serotonin Reuptake Inhibitors are often used as a first line treatment for moderate or severe depression. They help to achieve depression remission - the disappearance or nearly complete reduction of depressive symptoms. The SSRIs are all FDA approved for major depressive disorder but differ in their licensed indications for other mood conditions. Other indications include:
While members of this class are highly similar in their antidepressant action and side effect profile, they differ substantially in their molecular structure, metabolism, and pharmacokinetics. These varieties warrant that certain patients might profit more from one SSRI than another. Learn about Zoloft withdrawal symptoms and how to wean off the SSRIs. Serotonin and Norepinephrine reuptake inhibitors (SNRIs)
Serotonin and norepinephrine reuptake inhibitors (SNRIs) are newer class of antidepressants. They are dual-acting antidepressants and work by slowing down the reuptake of both serotonin and norepinephrine, but more selectively than other medications. Norepinephrine is thought to be involved more with alertness and energy, while serotonin influences mood. By increasing levels of both, SNRIs work on different aspects of depression. They may be superior to SSRIs in treating the painful physical symptoms of depression and in achieving the remission. Desvenlafaxine (Pristiq) is the active metabolite of venlafaxine. It was introduced by Wyeth in May 2008. Interestingly, in 2008, Wyeth withdrew its European application for desvenlafaxine (Ellefore). Milnacipran (Savella, Ixel) was approved by FDA in January 2009 only for fibromyalgia. It is currently not approved for depression in the United States. Norepinephrine and Dopamine Reuptake Inhibitors (NDRIs)
NDRIs increase the levels of norepinephrine and dopamine. Bupropion is the only NDRI that has been approved by the US FDA. Serotonin Antagonist /Reuptake Inhibitors (SARI)
Tricyclic antidepressants
The tricyclics (TCAs), named for their three-ring chemical structure, are the oldest antidepressants and have been used to treat depression since the 1950s. They work by increasing the levels of both neurotransmitters serotonin and norepinephrine. TCAs are not as specific in their mechanism of action as the newer antidepressant classes, they also affect other chemicals in the body. TCAs produce a wide range of unwanted effects and are dangerous in overdose. This often limits their usefulness. Despite being the old medications, TCAs still are used to treat severe (melancholic/endogenous) depression, dysthymia, and atypical depressions. There is evidence from studies dating to 1986 2, that clomipramine may be superior than some SSRIs for severe depression. Noradrenergic and Specific Serotonergic Antidepressants (NaSSA)
Noradrenaline reuptake inhibitors (NRIs)
Further reading
References
Last updated: March 2013 |
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