Over the 30 years that I've been in practice one of the biggest improvements in medical care has been in the medications used to treat depression. Prior to the introduction of the first selective serotonin reuptake inhibitor (SSRI), Prozac, in 1981 the treatments used to treat depression all had significant anti-cholinergic side effects. These side effects included sedation, dry mouth and constipation at treatment doses. The most commonly used antidepressant medications prior to the SSRIs were the tricyclic class of antidepressants, and in addition to these side effects at effective therapeutic windows, meaning at doses only moderately higher than needed for effective treatment there are serious potential toxic effects. These include seizures, cardiac arrhythmias and sudden death.
With the introduction of Prozac, which generic name is fluoxetine, we had an antidepressant that was well tolerated with far fewer annoying side effects and that was much safer to use. It has almost no life threatening side effects even in intentional over dosage. In addition it became clear that many of the SSRIs were effective for anxiety, panic disorder, pre-menstrual syndrome or pre-menstrual dysphoric disorder and obsessive compulsive disorder. Soon after fluoxetine came sertraline, paroxetine, citalopram, and other SSRIs.
Although the SSRI medications are effective in a major cases of major depression they do not work in all patients. A class of indications that functions to increase activity of the other major central nervous system neurotransmitter, norepinephrine, in addition to serotonin were introduced later. These became known as SNRIs for serotonin-norepinephrine reuptake inhibitors. Effexor, or venlafaxine, was the first of these medications to market. It fills a niche in patients who do not respond to the SSRIs, and others in its class have also become available.
Bupropion is an antidepressant that works primarily on the norepinephrine receptor, and is also better tolerated than the tricyclic medications and fills a niche too, having a benefit of not causing the most common SSRI side effect sexual dysfunction, primarily delayed or difficult orgasm in both men and women.
Depression is still a major cause of morbidity in many patients, but with the newer medications available today, alone or in combination with psychotherapy, most patients can get either a full remission or enough help to live a satisfying and productive life.