Psychiatric
Medicine
Associates
Where Research and Practice Meet
Education- Psychiatric Medications: Antidepressants
Selective Serotonin Reuptake Inhibitors (SSRIs)
SSRIs are a class of antidepressants that increase serotonin levels in the brain by inhibiting the serotonin transport pump. By doing so, more serotonin is allowed to remain in the synaptic cleft where it facilitates neuronal communication. Introduced in the 1980s, these medications revolutionized the treatment of depression because of their improved tolerability, lack of medical contraindications, and relative lack of drug interactions. Many of these medications are approved to treat major depressive disorder (MDD), generalized anxiety disorder (GAD), and obsessive compulsive disorder (OCD).
Common side effects: sexual dysfunction, nausea (transient), headache, sleepiness, insomnia.
Examples: fluoxetine (Prozac), sertraline (Zoloft), paroxetine (Paxil), fluvoxamine (Luvox) citalopram (Celexa), escitalopram (Lexapro).
Serotonin and Norepinephrine Reuptake Inhibitors (SNRIs)
SNRIs are a class of antidepressants that increase serotonin as well as norepinephrine levels in the brain by inhibiting the serotonin and norepinephrine transport pumps. By doing so, more of these neurotransmitters are allowed to remain in the synaptic cleft where they facilitate neuronal communication. SNRIs are thought to have a broader spectrum of action over SSRIs and are often more effective. They are usually used second-line.
Common side effects: sexual dysfunction, nausea (transient), headache, insomnia, sweating elevated blood pressure, constipation, sleepiness.
Examples: venlafaxine (Effexor), duloxetine (Cymbalta)
Numerous medications are available to treat depression and other psychiatric disorders. A common way depression is treated is through the use of antidepressants. Antidepressants consist of: Selective serotonin reuptake inhibitors (SSRIs), serotonin and norepinephrine reuptake inhibitors (SNRIs), tricyclics (TCAs), MAO-Inhibitors (MAOIs), and atypical antidepressants (trazodone and nefazodone, bupropion, and mirtazepine). Please see more information on these antidepressants below.
Tricyclic Antidepressants (TCAs)
Tricyclic antidepressants (TCAs) are the most heterogeneous group of antidepressants. They increase serotonin as well as norepinephrine levels in the brain by inhibiting the serotonin and norepinephrine transport pumps. By doing so, more of these neurotransmitters are allowed to remain in the synaptic cleft where they facilitate neuronal communication. The degree to which each transport pumps is inhibited depends on the individual drug. TCAs are a very effective class of medications with particular efficacy in the melancholic sub-type of depression.
TCAs, however, have some tolerability issues most notably anticholinergic side effects: dry mouth, constipation, blurred vision, urinary outlet obstruction, dizziness, increased appetite, weight gain and sedation. They can also interfere with cardiac electrophysiology and are contraindicated in some patients with heart problems.
Examples: amitriptyline (Elavil), imipramine (Tofranil), nortriptyline (Pamelor), desipramine (Norpramin), protriptyline (Vivactil), clomipramine (Anafranil), trimipramine (Surmontil), doxepin (Sinequan), maprotiline (Ludiomil) (tetracyclic)
Monoamine Oxidase Inhibitors (MAOIs)
Monoamine oxidase inhibitors (MAOIs) are some of the most effective antidepressants available. Their mechanism of action is unique and they work in the broadest of spectrums. They work by inhibiting the enzyme monoamine oxidase (MAO) whose role is to breakdown monoamines (serotonin, norepinephrine,and dopamine). By inhibiting MAO more serotonin, norepinephrine, and dopamine are available to facilitate neurotransmission. Because the action of MAOIs is so broad they must be used carefully. MAOIs have many serious drug and food interactions.
Common side effects: hypotension when standing, headache, insomnia, sexual dysfunction, constipation, dry mouth, restlessness.
Examples: tranylcypromine (Parnate), phenelzine (Nardil), isocarboxazid (Marplan) selegiline transdermal (Emsam)
Miscellaneous Antidepressants
Mirtazepine (Remeron) and nefazodone (Serzone) work by unique mechanisms of action and provide solid antidepressant and anxiolytic actions. Due to serotonin 2 and 3 (mirtazepine) receptor blocking these drugs are exceptional anxiolytics without the troubling side effects of sexual dysfunction, nausea (mirtazepine) and insomnia common to SSRIs and SNRIs.
Common side effects (mirtazepine): sedation, increased appetite, weight gain, dizziness dry mouth, dizziness.
Common side effects (nefazodone): sedation, dizziness, dry mouth, constipation, nausea.
Bupropion (Wellbutrin) is a unique medication that works by reuptake inhibition at the norepinephrine and dopamine transporter pumps. By doing so, more norepinephrine and dopamine is allowed to remain in the synaptic cleft where it facilitates neuronal communication. Bupropion is especially effective in people whose depression is characterized by, excessive sleep, loss of energy, and low motivation. It is unlikely to cause sexual dysfunction.
Common side effects: insomnia, anxiety, tremor, sweating, headache.