Antidepressants: Medicine for Depression

What are antidepressants?
Antidepressants are medicines used to treat people who have depression. Most people with depression get better with treatment that includes these medicines.

How do antidepressants work?
Antidepressants work by slowing the removal of certain chemicals from the brain. These chemicals are called neurotransmitters. Neurotransmitters are needed for normal brain function. Antidepressants help people with depression by making these natural chemicals more available to the brain.

How long will I have to take an antidepressant?
Antidepressants are typically taken for several months. In some cases, however, patients and their physicians may decide that a longer course of therapy is needed.

Do antidepressants have side effects?
Like most medicines, antidepressant drugs can have side effects. Not all people get these side effects. Any side effects you have will depend on the medicine your doctor has chosen for you.

What are the different kinds of antidepressants?
There are many different kinds of antidepressants, including: (1) tricyclic antidepressants, (2) selective serotonin reuptake inhibitors (SSRIs), (3) monoamine oxidase inhibitors (MAOIs), and (4) others. The tricyclics have been used to treat depression for a long time. They include amitriptyline (brand name: Elavil), desipramine (brand name: Norpramin), imipramine (brand names: Janimine, Tofranil) and nortriptyline (brand name: Pamelor). Common side effects caused by these medicines include dry mouth, blurred vision, constipation, difficulty urinating, worsening of glaucoma, impaired thinking and tiredness These antidepressants can also affect a person's blood pressure and heart rate.

A newer group of antidepressants includes drugs such as fluoxetine (brand name: Prozac), paroxetine (brand name: Paxil) and sertraline (brand name: Zoloft). These medicines are called SSRIs, for "selective serotonin reuptake inhibitors." They tend to have fewer side effects than the tricyclic antidepressants. Some of the side effects that can be caused by SSRIs include decreased appetite, nausea, nervousness, insomnia, headache, and sexual problems. People taking fluoxetine might also have a feeling of being unable to sit still. People taking paroxetine might have a dry mouth and feel tired. People taking sertraline might have runny stools and diarrhea.

The most common side effects in people taking venlafaxine (brand name: Effexor), which falls in the category "others," include nausea and loss of appetite, anxiety and nervousness, headache, insomnia and tiredness. Dry mouth, constipation, weight loss, sexual problems, increased blood pressure, increased heart rate and increased cholesterol levels can also occur.

Nefazodone (brand name: Serzone), also in the category "others," can give people headaches, blurred vision, dizziness, nausea, constipation, dry mouth and tiredness.

Will antidepressants affect my other medicines?
Antidepressants can have an effect on (interact with) many other medicines. If you're going to take an antidepressant, it's important to tell your doctor about all the other medicines you take, including over-the-counter medicines. The tricyclic antidepressants interact with many medicines.

The SSRIs can cause some other medicines to become stronger in your body. They have this effect on the tricyclic antidepressants and some drugs used to treat anxiety and sleeping disorders, such as diazepam (brand name: Valium). SSRIs might also have this effect on some medicines used to treat arrhythmias (irregular heart beats) and on haloperidol (brand name: Haldol).

Venlafaxine interacts with fluoxetine, paroxetine and sertraline. It also interacts with quinidine (brand names: Quinaglute, Quinidex), a medicine used to treat heart arrhythmias. Venlafaxine might interact with thioridazine (brand name: Mellaril). These medicines can increase the amount of venlafaxine in your body.

Nefazodone can increase the amount of triazolam (brand name: Halcion) and alprazolam (brand name: Xanax) in your body. Nefazodone can also interact with terfenadine (brand name: Seldane) and astemizole (brand name: Hismanal), which are drugs used for allergies. This could cause heart arrhythmias (irregular heart beats). Therefore, nefazodone should usually not be taken with terfenadine or astemizole.

Taking any other antidepressant with a MAOI might be fatal. MAOIs include phenelzine (brand name: Nardil) and tranylcypromine (brand name: Parnate). If your doctor wants you to start taking one of the other antidepressants, he or she will have you stop taking MAOIs for a while before you start taking the new medicine. This gives the MAGI time to clear out of your body.

This information provides a general overview on antidepressant medications and may not apply to everyone. Talk to your family doctor to find out if this information applies to you and to get more information on this subject.

This information is provided to you by your family doctor and the American Academy of Family Physicians.