Cocaine once transformed surgery as a local anaesthetic, then medicine abandoned it
Karl Koller's discovery that cocaine numbs tissue is ranked the second most important advance in the history of anaesthesia. Today it is almost gone from hospitals, displaced by safer drugs, while Andean communities still chew the coca leaf as they have for at least 8,000 years.
Cocaine is a stimulant belonging to the tropane alkaloids, extracted mainly from the leaves of two South American coca shrubs. Leaves are processed into a crude paste, then refined into cocaine base and finally the hydrochloride salt; making it from scratch in a laboratory is possible but too complicated to be used. In the brain it blocks the reuptake of serotonin, norepinephrine and dopamine, which produces euphoria, alertness and reduced appetite for up to about 90 minutes.
Its medical story hinges on numbing. Applied to tissue, cocaine blocks sensation and also constricts blood vessels, which made it a standard topical anaesthetic. Rising costs, tight regulation and its habit-forming nature drove the search for replacements. In the United States it remains a Schedule II drug, recognised as having some accepted medical use, such as numbing the airways or controlling bleeding in the nose and throat, but experts suggest it may soon fall out of clinical use entirely. The World Health Organization's essential medicines list explicitly excludes it.
The harms are serious. Short-term effects include a racing heart, high blood pressure, overheating and seizures, and overdose can cause stroke or cardiac arrest. It can also trigger paranoia and psychosis, and long-term use brings dependence and damage to the nasal tissues. About 20 million people used it in 2019, around 0.4 percent of adults worldwide, and since 1961 an international convention has required countries to criminalise recreational use.
The leaf itself is a different matter. Andean cultures from the Wari and Inca onward have chewed coca with alkaline ash or brewed it into tea against cold, hunger and altitude, though that effect has never been properly studied. Coca leaves remain legal in Peru, Bolivia and Argentina, where coca tea gives mild stimulation and Peru's state coca company sells leaf-based products.
Source: Cocaine
