What is a brief overview of antidepressant medications?

Introduction

In the early 1950s, psychotherapy was being used to treat people with major depression, but researchers were looking for more effective means of treatment, including pharmaceuticals. The first
antidepressant, iproniazid, was discovered accidentally while it was being used to treat tuberculosis. This monoamine oxidase inhibitor (MAOI) was found to improve the mood of the patients it was used to treat, and this suggested that depression could be treated through pharmacological means. When this first antidepressant was found to cause damage to the liver, it was replaced by imipramine, the first tricyclic antidepressant. Although imipramine was effective in treating nearly two-thirds of the cases of major depression, it was accompanied by a number of side effects, including sleepiness, palpitations, dry mouth, and constipation.

Second-Generation Antidepressants

Over the next quarter century, there were many attempts to synthesize antidepressants that were not fraught prowith side effects. It became apparent that both MAOIs and tricyclics affected multiple neurotransmitters and thus had numerous side effects. Therefore, researchers directed their attention to the development of a medication that would affect a single neurotransmitter only. In 1971, the first antidepressant medication to block the uptake of only one neurotransmitter was released in the form of fluoxetine (Prozac). This medication, still widely used, was the first selective serotonin reuptake inhibitor (SSRI). Since the 1970s, the second-generation antidepressants Prozac, paroxetine (Paxil), and sertraline (Zoloft) have been the most commonly used antidepressants.

Additional Antidepressants

The pharmaceutical industry has improved technology to the point where drug makers are capable of producing antidepressant medications that act on more than one neurotransmitter without causing large numbers of side effects. This category of drugs is commonly referred to as the dual reuptake inhibitors. The most common of these dual reuptake inhibitors are the serotonin-norepinephrine reuptake inhibitors (SNRIs). SNRIs include venlafaxine (Effexor) and duloxetine (Cymbalta). These SNRIs increase the levels of both serotonin and norepinephrine (noradrenaline) in the brain by inhibiting the reabsorption of these neurotransmitters by brain cells. Although the mode of action by which these dual reuptake inhibitors function is uncertain, it is believed that the increased levels of serotonin and norepinephrine in the brain enhance the transmission of nerve impulses, thereby improving and elevating affect. These and other modern antidepressants fall into the category of atypical antidepressants. Medications that are considered atypical antidepressants do not easily fit in any other category of drugs while inhibiting the uptake of several neurotransmitters within the brain. Another commonly used drug in this category is buproprion (Wellbutrin). These medications are typically taken orally and in pill form.

Natural Antidepressants

There are dozens of over-the-counter remedies and supplements that are marketed as antidepressants. For many of these substances, there is little, if any evidence of their safeness or effectiveness. One herbal supplement, St. John’s wort, is quite commonly used to counter depression and has been shown to be highly effective in some studies. This herbal remedy comes from a plant with yellow flowers. Derivatives of this plant were first used medicinally in ancient Greece. Although St. John’s wort was initially used to treat pain or for sedation, it has come to be used mainly as an over-the-counter antidepressant. Studies are ongoing to determine if St. John’s wort really has antidepressant effects or if people are merely responding to their own expectations (creating a placebo effect).

Bibliography

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