Antidepressants: Types of antidepressants

There are several classes of antidepressants; within each class there are many individual medications. While all antidepressants work well overall, no drug or type of drug works equally well for everyone who takes it. You may be advised to try another type of antidepressant or to use a combination of antidepressants to seek relief from your distress.

The different types of antidepressants are listed below in the order in which they are most commonly prescribed.

SSRIs—selective serotonin reuptake inhibitors

This group of drugs, including fluoxetine (Prozac)*, paroxetine (Paxil), fluvoxamine (Luvox), citalopram (Celexa), escitalopram (Cipralex) and sertraline (Zoloft), is usually the first choice for treatment of depression and anxiety problems. These medications are known to have milder side-effects than some other antidepressants. Buspirone (Buspar) is similar to SSRIs and has been found to help with anxiety but not depression.

Common side-effects include nausea, vomiting, diarrhea, weight gain, dry mouth, headaches, anxiety, sedation and a decrease in sexual desire and response. This group of drugs may also cause a jittery or restless feeling and sleep difficulties, such as problems falling asleep, waking in the night, vivid dreams or nightmares.

SNRIs—serotonin and norepinephrine reuptake inhibitors

This class of medications includes venlafaxine (Effexor), duloxetine (Cymbalta) and desvenlafaxine (Pristiq). These drugs are used to treat depression, anxiety problems and chronic pain.

Common side-effects include nausea, drowsiness, dizziness, nervousness or anxiety, fatigue, loss of appetite and sexual problems. In higher dosage, these medications may increase blood pressure.

NDRIs—norepinephrine and dopamine reuptake inhibitors

The medication available in this class is bupropion (Wellbutrin, Zyban). When used to treat depression, it is often given for its energizing effects, in combination with other antidepressants. It is also used to treat attention-deficit/hyperactivity disorder and as a smoking cessation aid.

Common side-effects are jitteriness and insomnia.

NaSSAs—noradrenergic and specific serotonergic antidepressants

Mirtazapine (Remeron), the medication available in this class, is the most sedating antidepressant, making it a good choice for people who have insomnia or who are very anxious. This medication also helps to stimulate appetite.

Common side-effects are drowsiness and weight gain.

Cyclics

This older group includes amitriptyline (Elavil), maprotiline (Ludiomil), imipramine (Tofranil), desipramine (Norpramin), nortriptyline (Novo-Nortriptyline) and clomipramine (Anafranil).

Because these drugs tend to have more side-effects than the newer drugs, they are not often a first choice for treatment. However, when other drugs do not provide relief from severe depression, these drugs may help.

Common side-effects include dry mouth, tremors, constipation, sedation, blurred vision, difficulty urinating, weight gain and dizziness. Because cyclics may cause heart rhythm abnormalities, your doctor should give you an electrocardiogram (ECG) before you take this medication.

MAOIs—monoamine oxidase inhibitors

Monoamine oxidase inhibitors, or MAOIs, such as phenelzine (Nardil) and tranylcypromine (Parnate) were the first class of antidepressants. MAOIs are effective, but they are not often used because people who take them must follow a special diet.

A newer MAOI, moclobemide (Manerix), can be used without dietary restrictions; however, it may not be as effective as other MAOIs.

Common side-effects include a change of blood pressure when moving from a sitting to a standing position (orthostatic hypotension), insomnia, swelling and weight gain.

Controlling side-effects

You can help to control possible side-effects on your own by:

getting regular exercise and eating a low-fat, low-sugar, high-fibre diet (e.g., bran, fruits and vegetables) to help prevent weight gain and constipation
using sugarless candy or gum, drinking water and brushing your teeth regularly to increase salivation and ease dry mouth
getting up slowly from a sitting or lying position to help prevent dizziness.

*Medications are referred to in two ways: by their generic name and by their brand or trade names. Brand names available in Canada appear here in brackets.

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