Drugs depressing agents, chemical

In the late 1950s, imipramine was noted to be effective for the symptomatic treatment of depression. A number of chemical congeners of imipramine have been synthesized and tested for antidepressant properties they are collectively known as TCAs. The TCAs are no longer considered first-line agents in the treatment of depression because of their prominent side effects and the need to monitor drug blood levels to avoid toxicity. 

Hoping to avoid such side effects as the sleep disruption and the occasional cardiac complications of the tricyclic antidepressants, and following the principle that clean drugs are theoretically preferable to dirty ones, the pharmaceutical industry has developed the selective serotonin reuptake blockers, a third generation of chemical agents to relieve depression. 

While it is true that dextromethorphan is not technically a member of the opiate family, it is distantly related in its chemical composition. Dextromethorphan is created by from levomethorphan, which is classified as an opioid, the synthetic or semi-synthetic relatives of the natural chemical family called the opiates. Levomethorphan has most of the same qualities of all drugs in the opiate and opioid classes. This includes strong suppressive effects on the respiratory system. It is these strong effects on the respiratory system that make dextromethorphan an effective anti-cough agent. Opiate and opioid compounds have anti-cough properties but produce greater overall respiratory depression than dextromethorphan. 

During the Cold War (1945-91), a great deal of research was directed to chemicals that were not necessarily lethal, but would merely temporarily incapacitate enemy personnel. In particular, the United States and the former Soviet Union investigated a wide number of pharmacological agents such as depressants, hallucinogens, belladonna drugs, and opiate derivatives for their potentials as incapacitants. 

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