19.01.3 Antidepressant Indications and Drug Classes

Antidepressant drugs are primarily indicated for major depression, in treatment of episodes and prevention of relapse. They may also be prescribed for atypical depression, post-natal depression, depression related to a medical illness or schizophrenia, pain, and anxiety disorders. Antidepressants are often given to sufferers of anxiety disorders due to the numerous overlapping symptoms, and because current anxiolytics such as benzodiazepines show dependence liability and can impair learning and memory.

Drugs currently used in Australia to treat depression fall into a number of major classes. The first antidepressant drugs to be synthesized were the tricyclic antidepressants (TCAs; imipramine being the prototype). Following TCAs were the irreversible monoamine oxidase inhibitors (MAOIs e.g. phenelzine), selective serotonin reuptake inhibitors (SSRIs; eg: fluoxetine), and serotonin-noradrenaline reuptake inhibitors (SNRIs; venlafaxine) and reversible inhibitor of monoamine oxidase A (RIMA; moclobemide).