Antidepressants

Tricyclics (Elavil, Anafranil, Norpramin, Sinequan, Tofranil, Pamelor, Vivactil, Surmontil)

MAOIs (Nardil, Parnate, Eldepryl)

Newer "Atypical" Antidepressants (Wellbutrin, Effexor, Remeron, Serzone, Cymbalta)

SSRIs (selective serotonin reuptake inhibitors):
These antidepressants have an effect on the levels of serotonin in the brain. SSRIs prevent this neurotransmitter from being reabsorbed. SSRIs are considered safer than many other antidepressants and generally have less bothersome side effects. Side effects normally include nausea, drowsiness, dizziness, and insomnia, as well as a variety of sexual disturbances such as difficulty with orgasm or decreased sexual desire.

SSRIs sometimes cause a withdrawal hypomania and must therefore be tapered slowly during the discontinuation period. The drugs in this class of antidepressants generally take between one and four weeks to take effect. Luvox (fluvoxamine) is the only SSRI antidepressant approved for use in children and the only one not approved by the FDA for the treatment of depression, though it has shown in clinical trials to be quite effective.

NOTE: Lexapro is a potent selective serotonin reuptake inhibitor (SSRI) approved by the FDA in August 2002 for the treatment of depression. Lexapro (escitalopram) is the active isomer of the antidepressant drug Celexa (citalopram). It is being promoted as more potent and possibly safer than older competitors.

TCAs (tricyclic antidepressants):
TCAs were one of the first two classes of antidepressant drugs developed to treat depressive illness. They get their name from the three rings in their chemical structure. TCAs have some effect on serotonin, but the primary effect of these drugs seems to be an inhibition of the reuptake of norepinephrine by neurons. By blocking removal of norepinephrine, these drugs seem to prolong or intensify norepinephrine's message to the cell in some way.

This class of drugs is used less frequently now, primarily because of the large number of side effects associated with these anitdepressants. Side effects of TCAs include sedation, dry mouth, constipation, orthostatic hypotension (dizziness when rising quickly from a sitting or lying position), weight gain, blurred vision, and numerous sexual difficulties. Overdoses of these drugs can be very dangerous.

MAOIs (monoamine oxidase inhibitors):
MAOIs were introduced around the same time as the TCAs. These drugs prevent the breakdown of dopamine, norepinephrine, and serotonin. MAOIs cause the inactivation of an enzyme in the body that metabolizes amine compounds. This enzyme, called monoamine oxidase (hence the name), eats up molecules of norepinephrine, serotonin, and several other neurotransmitters. Inactivation of this enzyme increases the amount of these compounds in the nervous system, which might explain the decrease in depressive symptoms. MAOIs also breakdown tyramine, a constituent of several foods which is normally broken down in the intestines before being absorbed. When taken in combination with certain foods or other medications, MAOIs can produce dangerously high blood pressure as the tyramine enters the bloodstream. For this reason, MAOIs are seldom used in the United States unless other antidepressants prove to be ineffective.

Wellbutrin (bupropion):
No one is certain how this drug works, but some believe it may have an effect on norepinephrine and dopamine. Wellbutrin tends to have a somewhat stimulating effect in some people, especially early in treatment. This medication may cause seizures in 0.4 percent of patients taking it, and is therefore contraindicated for use in those with a seizure disorder. It is also contraindicated in those with a history of anorexia or bulimia. Side effects of Wellbutrin normally include agitation, constipation, dizziness, dry mouth, and tremors. It may also cause weight loss in some people.

Effexor (venlafaxine):
This drug blocks the presynaptic reuptake of serotonin and norepinephrine. It is chemically unrelated to any other antidepressants on the market. Effexor must be taken multiple times during the day, which can be a problem for some patients. This medication may raise blood pressure and has a number of side effects including abnormal ejaculation, abnormal vision, drowsiness, anxiety, belching, blood in the urine, dizziness, dry mouth, and insomnia.

Remeron (mirtazapine):
This drug is a tetracyclic antidepressant that is available in a disintegrating tablet form. Side effects of this medication include constipation, dizziness, drowsiness, dry mouth, and increased appetite and weight gain. Rarely, Remeron can cause the blood disorder agranulocytosis. This disorder causes damage to the bone marrow and a failure to produce white blood cells. Agranulocytosis can be life threatening, but usually resolves itself once the drug is discontinued.

Serzone (nefazodone):
The SSRI alternative Serzone helps balance serotonin through a different brain mechanism, meaning fewer sexual and sleep-related side effects. The trade off is occasional liver toxicity. Side effects, that may go away during treatment, include headache, dry mouth, nausea, drowsiness, dizziness, weakness, constipation, lightheadedness, increased appetite, ringing in ears, and strange dreams.

Cymbalta (duloxetine):
This reuptake inhibitor of both serotonin and norepinephrine was given FDA approval for the treatment of major depressive disorder in adults. The recommended daily dose is 60 mg. Side effects include nausea, dry mouth, constipation, decreased appetite, fatigue, sleepiness, and increased sweating.

Desyrel (trazodone):
Desyrel is a modified cyclic antidepressant. The mechanism of action of this medication in humans is not clear, but in animals it selectively inhibits serotonin uptake by brain synaptosomes and increases the behavioral changes induced by the serotonin precursor, 5-hydroxytryptophan.

Side effects may include drowsiness, dizziness, lightheadedness, nausea/vomiting, headache and dry mouth.

This medication has been associated with the occurrence of priapism. In approximately 30 percent of reported cases, surgical intervention was required, some with permanent impairment of erectile function or impotence. Male patients taking this medication should immediately report prolonged erections to their doctor.

Edronax (reboxetine):
Edronax is a norepinephrine reuptake inhibitor similar to Strattera. This medication is used as an antidepressant in the UK and Australia, but was declined for approval by the FDA in 2006.

Side effects include dry mouth, constipation, insomnia, increased sweating, tachycardia, vertigo, urinary hesitance/retention and impotence. Combined usage of MAO inhibitors and reboxetine should be avoided.

Symbyax (fluoxetine and olanzapine):
Symbyax is a combination of fluoxetine (Prozac) and olanzapine (Zyprexa), and is the first antidepressant medication approved by the FDA to specifically treat bipolar depression.

Possible side effects, risks, and contraindications include those listed for Prozac and Zyprexa individually.