According to the National Institutes of Health, about 2 million of the 35 million Americans age 65 or older suffer from depression. Another 5 million suffer from less severe forms of depression. Drugs called antidepressants work to normalize brain chemicals called neurotransmitters. Neurotransmitters include serotonin, norepinephrine and dopamine. The elderly are more sensitive to side effects and drug interactions with other medicines. Elderly adults on antidepressants should be carefully monitored.
Selective Serotonin Reuptake Inhibitors
In the United States, the most widely prescribed antidepressants come from a class of drugs called selective serotonin reuptake inhibitors, or SSRIs. SSRIs include fluoxetine, fluvoxamine, sertraline, paroxetine, escitalopram and citalopram. SSRIs are effective and well-tolerated in the elderly. No research suggests a therapeutic superiority for one SSRI over another. If a patient does not respond to one type of SSRI they may respond to another.
Serotonin and Norepinephrine Reuptake Inhibitors
Therapeutic effects of antidepressants vary from person to person. If a patient doesn’t repond to one drug class there can switch to a drug in another class. According to MayoClinic.com, serotonin and norepinephrine reuptake inhibitors, or SNRIs, increase the levels of both serotonin and norepinephrine in the brain improving and elevating mood. Drugs in this group of antidepressants are also known as dual reuptake inhibitors and include venlafaxine, duloxetine and desvenlafaxine. They have been shown to be effective in treating depression.
Atypical Antidepressants
Some newer atypical antidepressant drugs target neurotransmitters such as norepinephrine and dopamine either alone or in combination with serotonin. Some atypical antidepressants include, bupropion, mirtazapine, trazodone and nefazodone. Based on side effect profile and patients needs, a doctor will decide which one is best for a particular patient.
Tricyclic Antidepressants
Tricyclic antidepressants, or TCAs, are considered older antidepressants. TCAs increase levels of serotonin and norepinephrine in the brain and to a lesser extent, dopamine. Before SSRIs launched on the drug prescription market, TCAs were the most widely prescribed. TCAs are shown to be effective in treating depression in the elderly but have some serious side effects. Side effects include cardiovascular problems, dry mouth, urinary retention, constipation and orthostatic hypotension.
Monoamine Oxidase Inhibitors
Monoamine oxidase inhibitors, or MAOIs, have been available since the 1950s. According to MayoClinic.com, MAOIs prevent the enzyme monoamine oxidase from metabolizing the neurotransmitters norepinephrine, serotonin and dopamine in the brain. As a result, these levels remain high in the brain, boosting mood and relieving depression. Side effects of MAOIs can also be serious and therefore they are usually reserved for people who have tried other antidepressant drugs first and have not worked.
