Cocaine and alcohol
Alcohol increases the speed of the effects of cocaine, but makes it harder to control your aggression, fears or anxieties. When taken together, cocaine and alcohol increase the dangers of each substance. Their simultaneous consumption can produce completely unpredictable effects. Researchers have found that when the liver combines cocaine and alcohol, it produces a third substance, coca ethylene. Coca ethylene, which acts with pharmacological mechanisms similar to those of cocaine, blocks the dopamine transporter, thus increasing the synaptic concentrations of this neurotransmitter in the dopaminergic pathways of the brain. Unlike cocaine, cocaethylene appears to inhibit the serotonin recapture pump less markedly. Serotonergic functions control dopaminergic functions by inhibiting them. If, therefore, the activity of serotonergic systems decreases, the control and inhibition of dopaminergic activity is attenuated. Consequently, by increasing dopaminergic activity significantly more than serotonergic activity, cocaethylene has a more pronounced euphoric action than cocaine. The longer duration of the effects of cocaine in combination with alcohol also seems to depend on the slow elimination of cocaethylene from brain tissue. However, the toxicity of cocaethylene is higher than that of cocaine. Cocaethylene has powerful cardiotoxic effects, while the accumulation and slow metabolism of cocaethylene in the liver appears to have toxic effects on liver cells. Therefore, the combination of cocaine and alcohol intensifies the euphoric effects of cocaine and significantly increases the risk of sudden death compared to taking cocaine alone.
Take a look at this site, which describes cases of poly-drug use:
Department of Anti-Drug Policies, Presidency of the Council of Ministers, Annual Report to Parliament on the State of Drug Addiction in Italy, 2008
Emerging Trends Project – Higher Institute of Health
Hardman, J.G., L.E. Limbird, P.B. Molinoff, R.W. Ruddon, A.G. Goodman. Goodman and Gilman’s The Pharmacological Basis of Therapeutics. 9th ed. New York, NY: McGraw-Hill, 1996.
Ellenhorn, M.J., S. Schonwald, G. Ordog, J. Wasserberger. Ellenhorn’s Medical Toxicology: Diagnosis and Treatment of Human Poisoning. 2nd ed. Baltimore, MD: Williams and Wilkins, 1997.