There are several types of antidepressant medications used to treat MDD. These include the selective serotonin reuptake inhibitors (SSRIs), the so-called "newer antidepressants," the tricyclics, and the monoamine oxidase inhibitors (MAOIs).
Serotonin Selective Reuptake Inhibitors (SSRIs)
The SSRI medications include fluoxetine, paroxetine, sertraline, fluvoxamine, citalopram and escitalopram. People with MDD are usually started on a low dose of these medications and the dose is usually gradually increased. Most people notice some improvement from these medications within 3-8 weeks of starting them.
Newer Antidepressants
A number of newer antidepressants including venlafaxine XR, nefazodone, bupropion SR, mirtazapine, and reboxetine have been recently approved for the treatment of MDD. These medications may be especially effective as "second-line" treatment in cases when a person has not responded that well to an SSRI.
Tricyclic Antidepressants (TCAs)
Imipramine and clomipramine have been demonstrated to be effective in the treatment of depression. There is also some evidence for the efficacy of desipramine, doxepin, amitriptyline, and nortriptyline in some cases. Even though they are effective, they are not usually a first-line treatment because of side-effects. They are mostly a second- or third-line choice for treating MDD.
Monoamine Oxidase Inhibitors (MAOIs)
The MAOIs including phenelzine, tranylcypromine and isocarboxazid, are effective in treating depression. However, while effective, the MAOIs have side-effects that make them mostly a second- or third-line choice for treatment.
The SSRIs and other newer antidepressants generally have fewer side effects than the tricyclics. It is often necessary to try a variety of antidepressants before finding the most effective medication or combination of medications for an individual. Sometimes the dosage must be increased to be effective. Although some improvements may be seen in the first few weeks, antidepressant medications must be taken regularly for 3 to 4 weeks (in some cases, as many as 8 weeks) before the full therapeutic effect occurs.
People are often tempted to stop medication too soon. They may feel better and think they no longer need the medication. Or, they may think the medication isn't helping them. It is important for patients to keep taking medication until it has a chance to work, although side effects may appear before the patient starts to feel better. Once they start to feel better, it is important to continue the medication for at least 6 to 9 months to prevent a recurrence of depression. Some medications must be stopped gradually to give the body time to adjust, and many can produce withdrawal symptoms if discontinued abruptly. For people with chronic or recurrent MDD, medication may have to be maintained indefinitely.
Antidepressant drugs are not habit-forming. However, antidepressants have to be carefully monitored to ensure that the correct dosage is being given.
For the small number of people for whom MAO inhibitors are the best treatment, it is necessary to avoid certain foods that contain high levels of tyramine, such as many cheeses, wines, and pickles, as well as medications such as decongestants. The interaction of tyramine with MAOIs can bring on a hypertensive crisis, a sharp increase in blood pressure that can lead to a stroke. Other forms of antidepressants require no food restrictions.
Antianxiety drugs or sedatives such as the benzodiazepines alprazolam and clonazepam are not antidepressants. They are sometimes prescribed along with antidepressants; however, they are not effective for MDD when prescribed alone.
For more detailed information about the assessment and treatment of MDD, please consult the following practice guidelines: Major Depression - Practice Guideline for the Treatment of Patients with Major Depressive Disorder. American Psychiatric Association.
Medications for Bipolar Disorder
Lithium has for many years been the first-line treatment for bipolar disorder, as it can be effective in smoothing out the mood swings common to this disorder. However, the use lithium must be carefully monitored as the range between therapeutic and a toxic dose is quite small. Lithium is not recommended for people with thyroid, kidney, or heart disorders or epilepsy. Fortunately, several other medications have been found to also be useful in controlling the mood swings associated with bipolar disorder, including two mood-stabilizing anticonvulsants, carbamazepine (Tegretol) and valproate (Depakote). Other anticonvulsants being used to treat bipolar disorder include lamotrigine (Lamictal) and gabapentin (Neurontin).
Most people who have bipolar disorder take more than one medication including, in addition to lithium and/or an anticonvulsant medications help manage agitation, anxiety, depression, or insomnia. It is important to try to find the right combination for each patient and to adequately monitor dosing and compliance.
For more detailed information about the assessment and treatment of bipolar disorder, please consult the following practice guidelines: Bipolar Disorder - Practice Guideline for Treatment of Patients with Bipolar Disorder. American Psychiatric Association.
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