Everything You Need to Know About Antidepressants


Antidepressants are the first line treatment against depression. Annual sales of antidepressants are approximately 50 billion dollars, making this class of drugs most commonly prescribed one of these days. Many pharmaceutical companies engaged in direct marketing of antidepressants to consumers through television and print media.

Thus, patients have a major influence on prescribing patterns of health professionals when it comes to this type of medication. Antidepressants are commonly prescribed, but after all, what exactly are antidepressants? How do they work? Are they effective?


This article is informational only, and is not intended as medical advice. People who are in search of assistance to obtain diagnosis and treatment of depression should consult their physician and / or pharmacist.

Depression or major depressive disorder - TDM, also called clinical depression or unipolar depression - occurs in about 15 million Americans a year. It can occur at any age (including children under 5 years), but most commonly affects people between 25 and 44 years. MDD affects approximately 20% of women and 10% of men [source: HealthyPlace.com (in English)]. TDM leads to lost productivity at work and school. And most important, is the leading cause of suicide (in English).

The TDM, unlike the short periods of “melancholy” is a persistent change in mood that can interfere with family relationships and self-esteem. Recurrent episodes can last for days, months or years. The TDM has physical and mental symptoms, which include:

* Depressed mood (sadness)
* Loss of interest or pleasure
* Sleep disruption
* Tired
* Feelings of worthlessness, despair, hopelessness and helplessness
* Changes in appetite, weight loss or weight gain
* Loss of sex drive
* Inability to think, concentrate or make decisions

To have a clinical diagnosis of MDD, these symptoms should occur frequently for a minimum period of two weeks.

These symptoms can also result from other diseases such as hypertension (in English), diabetes (in English), heart disease (in English) and epilepsy (in English). So it is possible that the depressive episode is a secondary symptom of another disease. Since there is no laboratory test for depression, doctors may perform several tests to rule out these other possible diseases. If all they are deleted, remains the TDM

How Antidepressants Work

Antidepressants are designed to block various aspects of the process of synaptic transmission in neurons that contain serotonin, norepinephrine and dopamine in the brain and, therefore, increase the levels of these neurotransmitters. With increasing levels of neurotransmitters, mood and emotions should stabilize and perhaps return to normal. However, as some of these neurotransmitters (like norepinephrine) are contained in the neural pathways in other parts of the brain and nervous system, some antidepressants can have side effects such as change in blood pressure (in English) and the production of saliva. Moreover, as the pathways involved in TDM are in the lower brain and brainstem, antidepressants can interfere with other functions such as appetite, sleep and sexual function.

Antidepressants are classified according to the neurotransmitters that affect and how they affect. Let’s look at the different types of antidepressants.

Selective reuptake inhibitors (SSRI)

SSRIs, antidepressants prescribed most often, were introduced in the mid 80s. SSRIs block the serotonin transporter back to the presynaptic cell. This action increases the concentration of serotonin in the synaptic cleft, raising the stimulation of postsynaptic cells. SSRIs include the following drugs:

* Fluoxetine (ProzacTM)
* Paroxetine (PaxilTM)
* Sertraline (ZoloftTM)
* Fluvoxamine (LuvoxTM)
* Citalopram (CelexaTM)
* Escitalopram (LexaproTM)

The various SSRIs are equally effective and well tolerated by patients. However, no one reacts the same way, so some patients may experience more side effects with one type of SSRI than another. Most antidepressants are administered more than once a day. But the active form of fluoxetine in the body have long half-life (stays longer) and, therefore, patients can take it once a day - minimizing the risk of forgetting a dose. At high doses, paroxetine and sertraline interfere in neurotransmission of dopamine and serotonin.

To reduce the side effects that may cause the patient to discontinue use of the drug, doctors usually begin SSRIs at low doses and slowly increase until the desired dose. Side effects include nausea (in English), dizziness (in English), vertigo (in English), vomiting (in English), insomnia (in English), anorexia (in English), anxiety (in English) and sexual dysfunction.

Tricyclic antidepressants and selective norepinephrine reuptake

Tricyclic antidepressants have been introduced in the late 50th and early 60th. Like the SSRIs, these compounds block the reuptake of norepinephrine by the presynaptic cell, thereby increasing its concentration in the synaptic cleft. Tricyclic antidepressants include:

* Nortriptyline (PamelorTM)
* Maprotiline (LudiomilTM)
* Desipramine (NorpramineTM)
* Amitriptyline (ElavilTM)
* Clomipramine (AnafranilTM)
* Imipramine (TofranilTM)

Tricyclic antidepressants affect heart rate and blood pressure, because norepinephrine is also a neurotransmitter used by the autonomic nervous system that controls blood pressure and heart rate. Side effects include postural hypotension (blood pressure below normal), tachycardia (rapid heartbeat), dry mouth, urinary retention and blurred vision. Tricyclic antidepressants are not used often because they have many side effects. However, for patients who can not tolerate SSRIs or other antidepressants, tricyclics are effective. Physicians should observe the patient closely for the appearance of serious side effects.

Tricyclic antidepressants are non-selective inhibitors of norepinephrine reuptake, because their chemical structures are similar to norepinephrine. Reboxetine (EdronaxTM) is a more specific reuptake inhibitor, for the best attaches reuptake transporter, but does not exist in the United States.

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