Cocaethylene


Cocaethylene is the ethyl ester of benzoylecgonine. It is structurally similar to cocaine, which is the methyl ester of benzoylecgonine. Cocaethylene is formed by the liver in small amounts when cocaine and ethanol coexist in the blood. Cocaethylene was first synthesized in 1885; its side effects were identified in 1989.

Metabolic production from cocaine

Cocaethylene is the byproduct of concurrent consumption of alcohol and cocaine as they are metabolized by the liver. Normally, the hepatic enzyme carboxylesterase catalyzes the hydrolysis of cocaine in the liver, producing two primarily biologically inactive metabolites—benzoylecgonine and ecgonine methyl ester. If ethanol is also present in the liver, a portion of the cocaine undergoes transesterification with ethanol rather than hydrolysis with water, producing cocaethylene.

Physiological effects

Cocaethylene increases the levels of serotonergic, noradrenergic, and dopaminergic neurotransmission in the brain and has a higher affinity for the dopamine transporter than cocaine, but has a lower affinity for the serotonin and norepinephrine transporters. These pharmacological properties make cocaethylene a serotonin-norepinephrine-dopamine reuptake inhibitor.
Although it cannot be bought, cocaethylene is largely considered recreational in and of itself, with stimulant, euphoriant, anorectic, sympathomimetic, and local anesthetic properties with a longer duration of action than cocaine. A 2000 study by Hart et al. on the effects of intravenous cocaethylene in humans found that "cocaethylene has pharmacological properties in common with cocaine, but is less potent," consistent with prior research.

Risks

While cocaethylene is more dangerous when administered alone, research suggests that the increase in risk from combining cocaine and ethanol is "thought to be due to alcohol decreasing the metabolism of cocaine and, therefore, increasing cocaine concentrations with only a minimal contribution to an increased risk from the formation of cocaethylene".

Use in research about combined use of cocaine and alcohol

Some studies suggest that consuming alcohol in combination with cocaine may be more cardiotoxic than cocaine and "also carries an 18 to 25 fold increase over cocaine alone in risk of immediate death".
Cocaethylene has been used as a biomarker for simultaneous alcohol and cocaine consumption. A 2021 study used this technique to show that people who consume alcohol and cocaine together have a higher risk of liver fibrosis.