What are the differences between all the different kinds of antidepressants?
As with most medication, antidepressants come in different formulations, with different
potential side effects, different actions in the body, and different sets of directions for
taking them properly. Most must be taken for at least four to six months, and often take
several weeks for any effect to be felt. Many antidepressants work to slow down the removal of
chemicals called neurotransmitters (such as serotonin and norepinephrine) from the brain, which
needs neurotransmitters to function normally.
- SSRIs: Selective serotonin reuptake inhibitors include fluoxetine (Prozac®), sertraline (Zoloft®), and paroxetine (Paxil®), and affect the neurotransmitter serotonin. Common side effects
include dry mouth, nausea, nervousness, insomnia, headache, and sexual problems. Some SSRIs are
also used to treat panic disorder, social anxiety disorder, general anxiety disorder,
obsessive-compulsive disorder (OCD), bulimia, post-traumatic stress disorder (PTSD), and
premenstrual dysphoric disorder (PMDD).
- SNRIs: Used to treat clinical depression, as well as anxiety disorder,
obsessive-compulsive disorder, and attention deficit hyperactivity disorder (ADHD),
serotonin-norepinephrine reuptake inhibitors act on both serotonin and norepinephrine. SNRIs
are a newer type of drug than SSRIs and include venlafaxine (Effexor®), atomoxetine (Strattera® ), and duloxetine (Cymbalta®). Side effects commonly seen with SNRIs include dry mouth,
drowsiness, dizziness, constipation, nervousness, increased perspiration, nausea, weakness,
weight loss, weight gain, decreased appetite, increased cholesterol, and sexual dysfunction in
- Tricyclic antidepressants (TCAs): This is an older class of medications than SSRIs
and includes amitriptyline (Elavil®), imipramine (Tofranil®), and desipramine (Norpramin®). These medications may affect heart rate and blood pressure.
Common side effects of tricyclics include dry mouth, blurred vision, constipation, difficulty
urinating, impaired thinking, and tiredness, and - for persons with glaucoma - a worsening of
this eye disease.
- MAOIs: Monoamine oxidase inhibitors are often used when other types of
antidepressants have failed to show an improvement. They are sometimes also effective for panic
disorder and bipolar depression. Their common side effects include weakness, tremor, and
headaches. Examples are phenelzine (Nardil®) and tranylcypromine (Parnate®). Because certain common foods and medications - including
chocolate, and cold and flu remedies - can cause a dangerous interaction with an MAOI, doctors
tend to reserve their use until other antidepressants have been tried unsuccessfully.
- Other medications: A number of antidepressant medications do not fit into the above
classes. These include trazodone (Desyrel®) and bupropion (Wellbutrin®). Side effects vary, as do the ways these medications act
in the body.
Everyone feels "down" or "blue" once in a while, but for some folks, it is a daily pattern
of depression. The good news about depression is that it is treatable - most often through talk
therapy, medication, or a combination of the two. Antidepressant medication - despite some
common side effects - can help lift a person from the depths of depression within weeks of
starting on medication therapy.
If one medication does not work for you or the side effects are too difficult for you to live with, keep in mind that there are many others your doctor may have you try. Make sure your doctor knows about any other medications - prescription and over the counter - you may be taking, as well as any supplements. And always check with your doctor or pharmacist with any questions about your medication therapy.
Read an in-depth report on depression in our Health Encyclopedia.
Find more information about specific drugs.
If you're looking for more specific answers to specific questions, ask a Walgreens pharmacist here.