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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 men.
  • 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.

Find more information about specific drugs.

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Answers to questions regarding information about medications or health conditions are not for diagnostic or treatment purposes and are not conclusive as to the presence or absence of any health condition. Consult your physician for diagnosis and treatment of your medical condition. The information provided is not a substitute for medical advice. Advances in medicine may cause this information to become outdated, invalid or subject to debate. Professional opinions and interpretations of the scientific literature may vary. Walgreens' terms of use and general warranty disclaimer apply to all services provided. If you are in need of immediate medical attention, contact your physician, poison control center or emergency medical professional. If you need to speak with a pharmacist for non-emergency matters, contact your local Walgreens pharmacist or call a pharmacist toll-free at 1 (877) 250-5823.

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