Medications to Treat Depression
Prescription antidepressant medication is the most common treatment for depression. Depression symptoms improve in approximately 80% of patients who take antidepressants. Treatment for a first depressive episode may last from 6 months to a year; recurrent depression typically warrants 2 years of antidepressant treatment; and chronic depression may require lifelong treatment. People respond differently to different medications, and in many cases, side effects and cost determine the type of medication used. Antidepressants may increase the risk for suicidal thinking in children and young adults.
In addition to considering side effects of an antidepressant, the physician and patient also address other important issues. For example, Prozac® effectively treats depression as well as bulimia nervosa (eating disorder that is sometimes associated with depression). Atypical antidepressants and SSRIs are the drugs most commonly prescribed for depression.
Antidepressant medications include the following:
- SSRIs (selective serotonin reuptake inhibitors)
- Atypical antidepressants, also called non-SSRIs
- TCAs (tricyclic antidepressants), also called tricyclics
- MAOIs (monoamine oxidase inhibitors)
Antidepressants may take 1–8 weeks to be effective, depending on the dosage and on the patient. Most physicians begin therapy at a low dosage, and patients who have difficulty adjusting to the drug may be treated with an even lower dose. In most cases, the dosage is gradually increased as the patient's tolerance and response to the drug increases. An effective concentration of the drug in the body must be attained before the patient experiences the desired results.
Antidepressants improve sleep and appetite, reduce anxiety, sharpen concentration, and restore energy levels. They are most effective in patients who have responded well to medication in the past, and who suffer from associated conditions such as anorexia and insomnia. A history of nonreaction to medication, personality disorder, delusions, psychosis, and chronic depression may indicate a poor response to medication.
Because people suffering from depression experience little or no sense of reward, they eventually may discontinue participation in activities that had been rewarding in the past. Unproductiveness, disinterest, and depression are often the result. Antidepressant medications increase the levels of monoamine neurotransmitters (i.e., serotonin, dopamine, norepinephrine) to elevate mood and restore a sense of well-being.
How Antidepressants Work
It is thought that depression is predominantly caused by insufficient levels of monoamine neurotransmitters in the brain, and this theory is supported by antidepressant drug treatment. Signals from the brain are transported by neurotransmitters across the gap (synaptic cleft) between nerve cells. Antidepressants increase the concentration of one of these neurotransmitters in the "gap" (e.g., SSRIs increase concentrations of serotonin). Sustained levels of neurotransmitters improves neurotransmission, which improves and elevates mood.
Side Effects of Antidepressants
Because available medications may take several weeks to take effect, patients commonly experience side effects before they experience benefits. The abrupt discontinuation of antidepressant medication is not recommended. The dosage is gradually tapered to avoid the intensification of side effects and "rebound effect," that is, a sudden onset of a severe depressive episode.
These drugs include the following:
- Citalopram (Celexa®)
- Escitalopram (Lexapro®)
- Fluoxetine (Prozac®)
- Fluvoxamine (Luvox®)
- Paroxetine (Paxil®)
- Sertraline (Zoloft®)
Side effects of SSRIs include sexual side effects, sun sensitivity, and slight weight loss. One-half of patients who take these medications experience one or more sexual side effects, including loss of libido, inability to experience orgasm, erectile dysfunction (in men), and vaginal dryness (in women). If these effects are intolerable, another medication can be prescribed.
In March 2012, the FDA approved the first generic version of Lexapro (escitalopram tablets) to treat depression and general anxiety disorder in adults. This medication is approved in three doses: 5 milligram, 10 mg and 20 mg.
These drugs, which have different mechanisms of action, include the following:
- Bupropion (Wellbutrin®)
- Velafaxine HCl (Effexor® XR)
Atypical antidepressants may cause the following side effects:
- Dry mouth
Tricyclic antidepressants generally are not the first choice for treatment because they may cause severe side effects. In high doses, they may cause seizures, stroke, and heart attack. The abrupt discontinuation of a TCA is not recommended and may cause headache, nausea, and malaise, and may intensify side effects.
TCAs include the following:
- Amitriptyline (Elavil®)
- Amoxapine (Asendin®)
- Clomipramine (Anafranil®)
- Desipramine (Norpramin®)
- Doxepin (Sinequan®)
- Imipramine (Tofranil®)
- Maprotiline (Ludiomil®)
- Nortriptyline (Aventyl®)
- Protriptyline (Vivactil®)
- Trimipramine (Surmontil®)
Side effects of these drugs include:
- Blurred vision
- Changes in appetite
- Decreased libido
- Dry mouth
- Impaired concentration
- Increased heart rate
MAOIs interact with tyramine, a chemical found in foods such as cheese, yeast products (e.g., beer), and chocolate. This interaction can result in a hypertensive crisis, which can be fatal. The risk is significant enough that many physicians avoid prescribing MAOIs. These drugs include phenelzine (Nardil®) and isocarboxazid (Marplan®).
Side effects are similar to those caused by TCAs and a potentially fatal condition called tyramine-induced hypertensive crisis.
In November 2007, the U.S. Food and Drug Administration (FDA) approved aripiprazole (Abilify®) for use in adults as an add-on treatment for major depressive disorder that does not respond to antidepressant therapy. Recent studies show that patients who take this drug in addition to antidepressants may experience an improvement in symptoms. Side effects include restlessness, insomnia, fatigue, and constipation.
SSRI and 5HT 1A Partial Agonist
In January 2011, the FDA approved vilazodone hydrochloride (Viibryd™) for the treatment of major depressive disorder in adults. Vilazodone is a combination of two medications: a selective serotonin reuptake inhibitor (SSRI) and a 5HT1a receptor partial agonist. The most common side effects are diarrhea, nausea, vomiting and insomnia. The medication should not be used with monoamine oxidase (MAO) inhibitors.
Second Generation Antipsychotics
Atypical antipsychotics, also called second generation antipsychotics, have been used to treat bipolar disorder and schizophrenia.
Over time, many doctors have seen success in using drugs in this class (together with antidepressants) off-label for the treatment of their depressed patients . Today, Aripiprazole (Abilify®), olanzapine (Symbyax®) and quetiapine (Seroquel XR®) are in fact approved by the FDA for this use.
If your symptoms have not improved on your antidepressant alone, tell your doctor. He or she may recommend adding one of these drugs to treatment plan.