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A Basic Guide to Antidepressants: Types, Dosage, Side Effects and Other Helpful Information

Antidepressants are medications used to alleviate depressive symptoms. How do they work? It depends on the type of antidepressant. Basically, depression medicines alter brain chemistry by effecting neurotransmitters, the brain’s chemical substances which are responsible for various functions within the body. For example, some depression drugs increase the neurotransmitter, Serotonin which is associated with mood (among other things such as sleep, memory, learning to name a few). Anti-depressant meds are grouped by drug class, which has similar properties and effects on the brain. Anti-depressants are also used to treat other psychiatric and medical conditions (see chart below). To obtain medications for depression, you need a prescription from a doctor, which can be filled at a pharmacy. (There are also natural anti-depressants that don’t require a prescription. Some popular natural depression remedies include St. John’s Wort and the amino acid 5-HTP.)

The best antidepressant will be prescribed based on many factors such as the symptoms you’re experiencing, other medicines you’re taking, other medical conditions you have and the anti-depressant’s potential side effects.

A common mistake is stopping antidepressant medications without talking to your doctor first. Many people stop because of side effects and never talk to their doctor about other options. Now there are many different types of medicine for depression. Sometimes it may take several tries to find the right anti depression medication for you. There are also other medications that can be taken to lessen side effects. So, it is important to work with a doctor who is knowledgeable or specializes in prescribing drugs for depression. For instance, it may be better to see a psychiatrist, a doctor who specializes in treating mental disorders than a general physician.

Another common error is not giving the depression medication a chance to work and stopping too soon. It can take several weeks or more before you will notice a positive difference from using anti-depressant drugs. Most side effects will stop or lessen with continued use. Some people may experience many, some or very few of the potential side effects associated with a particular anti-depressant.

Myths about antidepressant medicines include they will change your personality, deaden your feelings or make you feel numb. If these do occur, see you doctor. It may be from the depression or you may not be on the right medication or the dose may be incorrect.

It is important to discuss with your doctor if you are trying to get off (or switch) your antidepressant medication. Your doctor can help you taper off slowly and minimize any adverse effects. For example, some drugs prescribed for depression are short acting or have a short-half life (i.e. remain in your body for a short time) and as a result people may experience withdrawal symptoms or SSRI discontinuation syndrome (see below) when stopping too quickly.

There has been concern regarding increased suicide risk and worsening of depression with antidepressant use among children. Short-term studies have shown a greater risk of suicidal thinking and behavior among children who use antidepressant medication during the first few months of treatment. Upon starting depression medicine or a change in dosing, children should be carefully monitored for any unusual behavior, increase in depressive symptoms or suicidal thinking and behavior. Similarly, adults with depression and other psychiatric illnesses (and a history of suicidal behavior) should also be closely monitored.

Below are the different types of depression medication, broken down by drug class. The list of anti-depressants includes antidepressant names (brand / manufacturer & generic), typical daily dosage for an adult, potential antidepressant side effects and other common uses3. The information provided pertains to adults and not children.

Types of Anti-depressants

Selective Serotonin Reuptake Inhibitors (SSRIs)

SSRI medications change brain chemistry by increasing the neurotransmitter, Serotonin. This increase is accomplished by blocking the process (which is called reuptake) by which Serotonin is eliminated. They are the most popular class of antidepressant drugs that are prescribed because of their lower adverse effects and safety (higher toxic dose) compared to other types of depression medicine. SSRIs are also considered depression anxiety medications because they treat anxiety among other mental conditions. Overall, these anti-depressant drugs are not prescribed for treating manic depression (which is characterized by episodes of depression and/or extreme elevated mood or irritability).

For some SSRI medication, especially ones (e.g. Paxil, Zoloft, Effexor) that remain in the body for a short time, can cause a set of withdrawal symptoms called SSRI discontinuation syndrome when these anti-depressant medicines are stopped or decreased. When this occurs, you may feel like you have the flu and experience symptoms like fatigue, nausea, chills, diarrhea, headache, vomiting and dizziness. These symptoms will vary in intensity and may last from one to seven weeks.

Brand Name(s) (Manufacturer)

Generic Name
Typical Daily Dosage Range1 (Adult) Anti-depressant
Potential Side Effects2
(Forest Laboratories)


20-40 mg Nausea, dry mouth, drowsiness, insomnia, increased sweating, tremor, diarrhea, decrease in sexual ability
Other Common Uses: Social Anxiety, Posttraumatic Stress Disorder (PTSD), Premenstrual Dysphoric Disorder (PMDD), Panic, Obsessive Compulsive Disorder (OCD)
(Forest Laboratories)
Escitalopram 10-20 mg Nausea, insomnia, change in sexual desire / decrease in sexual ability, drowsiness, increased sweating, fatigue
Other Common Uses: Generalized Anxiety Disorder (GAD), Social Anxiety, PTSD, PMDD
Prozac / Serafem
(Eli & Lilly)
Fluoxetine 20-80 mg Nausea, insomnia, drowsiness, anxiety, nervousness, weakness, decreased appetite, tremor, dry mouth, sweating, change in sexual desire / decrease in sexual ability, diarrhea, akathisia (i.e. inner restlessness), irritability, hostility
Other Common Uses: OCD, Panic, Bulimia, PMDD, PTSD, Social Anxiety, Anxiety
(Solvay Pharmaceuticals)
Fluvoxamine 50-300 mg Nausea, headache, drowsiness, insomnia, nervousness, tremor, upset stomach, decreased appetite, dry mouth, vomiting, weakness, change in sexual desire / decrease in sexual ability, sweating
Other Common Uses: OCD, Social Anxiety, PTSD, PMDD, Panic
Paxil / Pexeva
(Glaxo Smith Kline) / (Synthon Pharmaceuticals)
Paroxetine 20-60 mg Weakness, sweating, nausea, decreased appetite, drowsiness, dizziness, insomnia, tremor, nervousness, change in sexual desire / decrease in sexual ability,dry mouth, constipation
Other Common Uses: Panic, Social Anxiety, OCD, PTSD, GAD, PTSD, Anxiety, PMDD
Sertraline 50-200 mg Dry mouth, insomnia, change in sexual desire / decrease in sexual ability, diarrhea, nausea, drowsiness, headache, dizziness,
tremor, upset stomach, sweating
Other Common Uses: Panic, OCD, PTSD, Social Anxiety, PMDD, GAD, Anxiety

Tricyclic Anti-depressants (TCAs)

A class of anti depression drug that is named after its chemical structure (a three ring molecular core). In addition to increasing levels of Serotonin, TCAs affect Norepinephrine, Dopamine and to varying degrees Acetylcholine and Histamine. In the past, these depression pills were the first choice in treating depression until SSRIs and new antidepressant medications were developed. These anti-depressants are prescribed less often because they have more unpleasant side effects than SSRI medications and some are potentially dangerous such as a lower toxic/lethal dose and effects on the heart. Tricyclics are often prescribed when someone is experiencing resistant depression or not responding to SSRI meds.

Because its effect on the neurotransmitters Histamine and Acetylcholine, Tricyclic medicines can cause drowsiness and anticholinergic side effects which include dry mouth, rapid heartbeat, blurred vision, constipation and difficulty urinating. TCA medication use in the elderly should be done with caution because of these adverse effects and others such as confusion, delirium and sedation. Overall, this class of anti-depressants have similar side effects, but differ in terms of level of sedation and anticholinergic side effects (see table below).

Example of Potential Side Effects2: dry mouth, sedation or drowsiness, blurred vision, rapid heartbeat, constipation, difficulty urinating, confusion or disorientation, nausea, increased appetite or weight gain, tremor, dizziness when changing positions, hypotension, weakness, change in sexual desire / decrease in sexual ability, irregular heart rhythm, headache

Brand Name(s) (Manufacturer)

Generic Name
Typical Daily Dosage Range1 (Adult) Anti-depressant
Potential Side Effects2,5


75-150 mg High sedation, high anticholinergic side effects
Ascendin        (Wyeth-Ayerst Laboratories /Lederle Laboratories) Amoxapine 200-300 mg Low sedation, moderate anticholinergic side effects
Anafranil (Mallinckrodt Pharmaceuticals) Clomipramine 100-250 mg Low sedation, low anticholinergic side effects
Other Common Uses: OCD
Norpramin / Pertofrane      (Sanofi-Aventis) Desipramine 100-300 mg Low sedation, low anticholinergic side effects
Sinequan / Adapin
(Pfizer) / (Lotus Biochemical)
Doxepine 150-300 mg High sedation, high anticholinergic side effects
Other Common Uses: Anxiety
Tofranil    (Mallinckrodt Pharmaceuticals) Imipramine 75-200 mg Moderate sedation, moderate anticholinergic side effects
Other Common Uses: Enuresis (i.e. bedwetting)
Aventyl / Pamelor
(Eli & Lilly) / (Mallinckrodt Pharmaceuticals)
Nortriptyline 25-100 mg Moderate sedation, low anticholinergic side effects
Vivactil / Triptil (Odyssey Pharmaceuticals) / (Merck & Company) Protriptyline 15-60 mg Low sedation, moderate anticholinergic side effects
Surmontil     (Odyssey Pharmaceuticals) Trimipramine 75-200 mg High sedation, moderate anticholinergic side effects

Monoamine Oxidase Inhibitors (MAOIs)

MAOIs were the first medicines developed to successfully treat depression. MAOIs are named after an enzyme (monoamine oxidase) that breaks down neurotransmitters which include Serotonin and Norepinephrine. Since MAOIs inhibit this break down, the levels of these neurotransmitters are increased. These depression medications are used to treat severe or atypical depression which is associated with symptoms such as anxiety, increased sleeping, overeating, weight gain, rejection sensitivity and temporary improvement in mood in response to positive events. These anti-depressants are often prescribed when other depression meds have not been effective.

These medicines are not prescribed as often as SSRIs or TCAs because of serious side effects and interactions with certain foods. For example, foods containing a high level of tyramine cannot be taken with MAOIs (e.g. aged cheeses, sour cream, yogurt, cured meats, dry sausages, wine, beer, soy sauce, banana peel, liver, fava or broad bean pods, anchovies, pickled herring, caviar, yeast extracts and sauerkraut). MAOI anti-depressants and these foods may interact and increase blood pressure to dangerous levels. There are many drug interactions (e.g. over-the-counter cold medicines, nasal sprays) with these antidepressant meds. It is important to inform your doctor about any other medications you are taking while on MAOIs.

Example of Potential Side Effects2: dietary interactions, headache, insomnia or sleep problems, change in blood pressure (blood pressure crisis), drowsiness, nausea, dry mouth, constipation, blood changes/problems, dizziness when changing positions, fluid retention, tremors, change in sexual ability, weakness, stomach upset or pain, blurred vision, restlessness, urinary problems

Brand Name(s) (Manufacturer)

Generic Name
Typical Daily Dosage Range1 (Adult)
Marplan          (Oxford Pharmaceutical Services) Isocarboxazid 20-60 mg
Phenelzine 45-90 mg
(Glaxo Smith Kline)
Tranylcypromine 30-60 mg

Other Antidepressant Medicines

These drugs don’t fit in the above categories. These anti-depressants have a combination of different properties and effects on neurotransmitters. Most of these depression medications also affect Serotonin and/or Norepinephrine except Wellbutrin, which affects more Dopamine and Norepinephrine than Serotonin and Eldepryl, which primarily affects Dopamine.

Brand Name(s) (Manufacturer)

Generic Name
Typical Daily Dosage Range1 (Adult) Anti-depressant
Potential Side Effects2
Wellbutrin / Zyban
(Glaxo Smith Kline)


200-450 mg Anxiety, insomnia, dry mouth, headache, dizziness, loss of appetite/weight loss, tremor, restlessness, nausea, vomiting, sweating, constipation, increased risk of seizure, skin rash, high blood pressure
Other Common Uses: Quitting Smoking, Attention-Deficit Hyperactivity Disorder, Seasonal Affective Disorder
(Eli & Lilly)
Duloxetine 20-80 mg Nausea, dry mouth, constipation, decreased appetite, fatigue, drowsiness, increased sweating, dizziness, skin rash, blurred vision
Other Common Uses: GAD, Social Anxiety, PTSD, PMDD, Nerve associated pain
Ludiomil        (Novartis Pharmaceuticals) Maprotilin 75-225 mg Drowsiness, upset stomach, weakness, anxiety, insomnia, dry mouth, nightmares, decreased appetite, skin more sensitive to sunlight, constipation, change in sexual desire / decrease in sexual ability, increased sweating, blurred vision
Other Common Uses: Anxiety, Nerve associated pain
Remeron / Soltab (Organon) Mirtazepine 15-45 mg Increase in appetite or weight gain, drowsiness, water retention, dizziness, headache, drowsiness, tremor, skin rash
(Bristol-Myers Squibb)
Nefazodone 300-600 mg Drowsiness, nausea, dry mouth, dizziness, lightheadedness, blurred vision, skin rash, ringing in ears, diarrhea, muscle tension, shortness of breath, insomnia, headache, vomiting, increased appetite, tremor, tingling sensations, constipation, agitation, flushing
Other Common Uses: Anxiety, PTSD
Eldepryl      (Somerset Pharmaceuticals) Selegiline 5-10 mg Nausea, dizziness, stomach pain, drowsiness, insomnia, mild headache, dry mouth, diarrhea, increase in unusual body movements, vomiting
Other Common Uses: Quitting Smoking, Parkinson’s Disease
Desyrel           (Bristol-Myers Squibb) Trazodone 150-400 mg Drowsiness, dry mouth, dizziness, lightheadedness, nausea, vomiting, headache, blurred vision, constipation, diarrhea, low blood pressure, confusion, muscle aches
Other Common Uses: Sleep Aid
Effexor           (Wyeth-Ayerst Laboratories) Venlafaxine 75-375 mg Weakness, sweating, nausea, constipation, vomiting, drowsiness, dry mouth, dizziness, nervousness, anxiety, tremor, blurred vision, sexual dysfunction
Other Common Uses: Panic, GAD, Social Anxiety, PTSD, PMDD


  1. Some people may take an effective dose that is outside this range. Information for Typical Daily Dosage Range obtained from “Alphabetical Checklist of Dosages and Uses of 100 Common Psychotropic Medications“ by Ed Zuckerman, Ph.D. and Dan Egli, Ph.D.
  2. The side effects described give only a sample of the most common and do not comprise a complete listing. Other less common and rarer adverse effects have not been included. Please consult a psychiatrist, physician or health care provider for more information. Side effects information was obtained from the drug’s manufacturer.
  3. Other common uses include FDA approved and anecdotal uses (commonly reported but not officially studied). Other common uses do not comprise a complete listing.
  4. The manufacturer has withdrawn this anti-depressant. Often the generic version is still available.
  5. Source: “A Primer of Drug Action” by Robert M. Julien, M.D. Ph.D.

Also see: [ natural remedies ] [ depression help ] [ signs ]



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