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What are the different kinds of antidepressants? What kinds of side effects do they have?

Antidepressants are put into groups based on which chemicals in the brain they affect. There are many different kinds of antidepressants, including:

Selective serotonin reuptake inhibitors (SSRIs)

• citalopram
• escitalopram
• fluoxetine
• fluvoxamine
• paroxetine
• sertraline

SSRIs affect a chemical in the brain called serotonin. If a person has never tried an antidepressant before, SSRIs are usually the first kind of antidepressant medicine your healthcare provider will recommend. These medicines tend to have fewer side effects than other antidepressants. Some of the side effects that SSRIs can cause include dry mouth, nausea, nervousness, insomnia, sexual problems, and headache.

Serotonin and norepinephrine reuptake inhibitors (SNRIs)

• desvenlafaxine
• duloxetine
• venlafaxine

SNRIs affect two chemicals – serotonin and norepinephrine – in the brain. These medicines are sometimes chosen because they don’t interfere with certain other medicines. Some common side effects caused by these medicines include nausea (especially in the first two weeks), loss of appetite, anxiety and nervousness, headache, insomnia, and tiredness.

Dry mouth, constipation, weight loss, sexual problems, increased heart rate, and increased cholesterol levels also can occur.

Atypical antidepressants

• bupropion
• mirtazapine
• trazodone

These medicines are called “atypical” because they don’t easily fit into their own category. The side effects depend on what drug you are taking, but like most antidepressants, these medicines can cause nausea, fatigue, nervousness, dry mouth, and headache. Trazodone is sometimes used along with an SSRI to help with insomnia with depression.

Bupropion is sometimes recommended for people who also have attention-deficit hyperactivity disorder, cocaine dependence, or who want to quit smoking. You should not take this kind of medicine if you have a seizure disorder or bulimia. Some of the common side effects of bupropion include agitation, nausea, headache, loss of appetite, and insomnia. However, this type of antidepressant medication typically has less risk of sexual side effects.

Tricyclic antidepressants

• amitriptyline
• clomipramine
• desipramine
• doxepin
• imipramine
• nortriptyline
• trimipramine

Tricyclic antidepressants affect the brain chemicals serotonin, norepinephrine, and dopamine. This type of antidepressant is one of the oldest types of antidepressants. The drugs are still effective, but they are used less often because the side effects are more common. Side effects caused by these medicines can 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. They are not usually recommended for older patients, people who have glaucoma, or men who have enlarged prostates.

Monamine oxidase inhibitors (MAOIs)

• phenelzine
• selegiline
• tranylcypromine

MAOIs affect an enzyme in the brain called monamine. These drugs are typically used as a last resort, when other types of antidepressants haven’t worked. They can have serious side effects, including weakness, dizziness, headaches, and trembling. Taking an MAOI antidepressant and eating certain foods or taking another antidepressant or certain over‑the‑counter cold and flu medicines can cause a dangerous reaction. You should not take an MAOI unless you clearly understand what medicines and foods to avoid.