Most antidepressants work by manipulating the way certain chemicals in the brain function, but each type may act in a slightly different way or affect different brain chemicals. Antidepressants are put into specific classifications depending upon which brain chemicals are affected by its use, according to the American Academy of Family Physicians.
Selective Serotonin Reuptake Inhibitors
Selective serotonin reuptake inhibitors (SSRIs) are frequently prescribed to treat depression but may also contain some unwanted side effects. Sexual dysfunction, dry mouth, headache, diarrhea, nervousness, rash, agitation, restlessness, nausea, increased sweating, drowsiness, insomnia or weight gain are some possible side effects, although specific side effects may vary depending on the specific medication taken. Commonly prescribed SSRI antidepressants include citalopram, escitalopram, fluoxetine, paraxetine and sertraline. A fluvoxamine and olanzapine combination medication can also be prescribed to treat bipolar depression, and is classified as both an SSRI and an atypical antipsychotic.
Serotonin and Norepinephrine Reuptake Inhibitors
Serotonin and norepinephrine reuptake inhibitors (SNRIs) also are used to treat depression. As in the case of SSRIs, side effects will vary depending upon the specific SNRI medication taken, but may include nausea, vomiting, gas, constipation, agitation, dizziness, insomnia, trouble sleeping, abnormal dreams, sweating, dry mouth, tremors, anxiety, changes in vision, headache and sexual dysfunction. Venlafaxine is a type of SNRI that may be a good choice when other types of antidepressants are unsuccessful, but an increase in blood pressure may occur with its use. Desvenlafaxine is like venlafaxine, but may cause fewer side effects, according to the Mayo Clinic. Duloxetine can cause many side effects and is not recommended for everyone, particularly not for heavy drinkers or people with kidney or liver problems, but it may work to help relieve the physical pain as well as treat the depression.
Atypical Antidepressants
Atypical antidepressants are medications that do not fit into a specific classification. These medications may cause less sexual dysfunction than other types of antidepressants. Bupropion, in particular, causes less sexual side effects than all other antidepressants, according to the Mayo Clinic. However, people with eating disorders or seizure disorders should avoid this medication. Trazodone and mirtazapine are sedating antidepressant medications that are often used as a sleep aids. Nefazodone was a common atypical antidepressant, but is no longer prescribed due to links to serious liver problems.
Tricyclic and tetracyclic antidepressants
Although tricyclic and tetracyclic antidepressants were once commonly prescribed, they are not usually the best choice for most people now due to their numerous side effects, according to the Mayo Clinic. Dry mouth, difficulty urinating, sedation, constipation, weight gain and sexual dysfunction are common when using these medications. However, in certain situations, a low dose of this type of antidepressant may be used in combination with another antidepressant. Tricyclic and tetracyclic antidepressants include amitriptyline, desipramine, clomipramine, doxepin, potriptyline, imipramine, trimipramine, nortriptyline, amoxapine and maprotiline.
Monoamine oxidase inhibitors (MAOIs)
Monoamine oxidase inhibitors (MAOIs) are not frequently prescribed for the treatment of depression due to many potentially serious side effects, according to the Mayo Clinic. These side effects can include dry mouth, dizziness, difficulty urinating, twitching muscles, sleep problems, upset stomach, sexual dysfunction, and they can cause potentially fatal high blood pressure when combined with other medications or certain foods or beverages. However, if the other forms of antidepressants fail, MAOIs can still be effective. Isocarboxazid, phenelzine, tranylcypromine and selegiline are MAOIs. Emsam, a transdermal patch worn on the skin, is also available and may have fewer side effects than other MAOI pills.
