There are five basic classifications of medications used for treatment of major depression. Newer types of drugs such as selective serotonin reuptake inhibitors and serotonin and norepinephrine reuptake inhibitors tend to are popular largely because they don't have as many or as serious side effects as older antidepressants. Some medications work better for some people than they do for others, so your doctor may need to try several different types of drugs before she finds one that works best for you.
SSRIs
SSRIs, or selective serotonin reuptake inhibitors, tend to be the first type of antidepressant many doctors try on their patients who suffer from depression, according to the Mayo Clinic. This type of medication is thought to work by preventing the brain from reabsorbing serotonin, a neurotransmitter in the brain. The most common types of these SSRIs are sertraline, citalopram, paroxetine, escitalopram, fluvoxamine and the first one marketed, fluoxetine. Potential side effects from SSRIs include convulsions, headaches, restlessness, rapid heartbeat, mood changes, hostility and sexual problems such as failure to reach orgasm in both men and women.
SNRIs
Serotonin and norepinephrine reuptake inhibitors, or SNRIs, work by decreasing the reabsorption of both serotonin and norepinephrine in the brain. There are three types of antidepressants under the SNRI classification: duloxetine, venlafaxine and desvenlafaxine. Side effects from SNRIs may include pain in the eyes, vision blurring or blindness. They also may cause a variety of others from diarrhea and agitation to irregular heartbeats and convulsions.
Tricyclics and Tetracyclics
Such antidepressants as the generics maprotiline, amitriptyline, amoxapine, clomipramine, protriptyline, doxepin, nortriptyline and others are classified as tricyclic and tetracyclic antidepressants. They predate SSRIs and SNRIs. They tend to have more side effects than newer antidepressants, according to the Mayo Clinic. Those may include a coma, convulsions, depression, agitation, pain in the chest, vision problems, hostility, loss of hearing, nightmares, nausea and others.
MAOIs
Monoamine oxidase inhibitors or MAOIs are not typically a first course of action to fight depression, the Mayo Clinic states. They include isocarboxazid, tranylcypromine and phenelzine. One of the reasons these are not used as much as newer antidepressants is that they can cause hypertension at levels that can be fatal. Other side effects include confusion, dizziness, jerking motions, troubled thinking, fear, irritability, lack of emotion, unusual heartbeats, constipation or diarrhea among others.
Atypical
Antidepressants that don't categorize easily are called atypical antidepressants. These include nefazodone, bupropion, mirtazapine and trazodone. Nefazodone, formerly marketed as Serzone but no longer available in the United States under that name, according to RxList.com, has been reported as causing severe liver failure. Bupropion, according to the Mayo Clinic, it has fewer sexual side effects than all other antidepressants. It also has been used as an aid for smoking cessation and appetite suppression. Trazodone is a mood elevator. Its side effects may include confusion, concentration difficulties, headaches and nervousness. Mirtazapine also may cause mood changes, unusual thought processes, seizures, lowered libido and changes in the menstrual cycle.
