Liver function tests in non-parenteral cocaine users

Effects of concurrent use of alcohol and cocaine

The combination of alcohol and cocaine is popular among drug users, perhaps because of more intense feelings of 'high' beyond that perceived with either drug alone, less intense feelings of alcohol-induced inebriation and tempering of discomfort when coming down from a cocaine 'high'. A review is presented of the medical literature on psychological and somatic effects and consequences of combined use of alcohol and cocaine in man. The search was carried out with Medline, the Science Citation Index/Web of Science and Toxline. Exclusion and inclusion criteria for this search are identified. There is generally no evidence that the combination of the two drugs does more than enhance additively the already strong tendency of each drug to induce a variety of physical and psychological disorders. A few exceptions must be noted. Cocaine consistently antagonizes the learning deficits, psychomotor performance deficits and driving deficits induced by alcohol. The combination of alcohol and cocaine tends to have greater-than-additive effects on heart rate, concomitant with up to 30% increased blood cocaine levels. Both prospective and retrospective data further reveal that co-use leads to the formation of cocaethylene, which may potentiate the cardiotoxic effects of cocaine or alcohol alone. More importantly, retrospective data suggest that the combination can potentiate the tendency towards violent thoughts and threats, which may lead to an increase of violent behaviours.

Methadone-related opioid agonist pharmacotherapy for heroin addiction. History, recent molecular and neurochemical research and future in mainstream medicine

In 1963, Professor Vincent P. Dole at the Rockefeller University formed a small team to develop a pharmacotherapy for the management of heroin addiction. They hypothesized that heroin addiction is a disease of the brain with behavioral manifestations, and not merely a personality disorder or criminal behavior and began to address the specific question of whether a long-acting opioid agonist could be used in the long-term maintenance treatment of heroin addiction. Over the next 35 years, many studies documented the safety, efficacy and effectiveness of methadone pharmacotherapy for heroin addiction, but Federal regulations and stigmatization of heroin addiction prevented implementation of treatment. Finally, in 1999, NIH published a report unequivocally supporting methadone maintenance pharmacotherapy for heroin addiction. Two other effective opioid agonist treatments have been developed: the even longer acting opioid agonist l-alpha-acetylmethadol (LAAM) has been approved for pharmacotherapy for heroin addiction, and still under study is the opioid partial agonist-antagonist buprenorphine-naloxone combination. A variety of studies, both laboratory based and clinical, have revealed the mechanisms of action of long-acting opioid agonists in treatment, including prevention of disruption of molecular, cellular and physiologic events and, in fact, allowing normalization of those functions disrupted by chronic heroin use. Recent molecular biological studies have revealed single nucleotide polymorphisms of the human mu opioid receptor gene; the mu opioid receptor is the site of action of heroin, the major opiate drug of abuse, analgesic agents such as morphine, and the major treatment agents for heroin addiction. These findings support the early hypotheses of our laboratory that addiction may be due to a combination of genetic, drug-induced and environmental (including behavioral) factors and also, that atypical stress responsivity may contribute to the acquisition and persistence of, as well as relapse to, use of addictive drugs.

Liver disease due to illicit substance use

While the adverse neurological, cardiovascular, renal, haematologic and musculoskeletal consequences of the use of various illicit substances are widely appreciated, less attention has been directed to possible hepatotoxic effects. This is an important issue in view of increasing evidence in both experimental animals and humans that the use of some illicit substances may be associated with substantial liver damage, leading on occasion to acute liver failure. This manuscript reviews the effects on the liver of some of the most commonly used illicit substances, including ecstasy (3,4-methylenedioxymethamphetamine), other amphetamines, cocaine, heroin, angel dust (phencyclidine), lysergic acid diethylamide and marijuana. Additional causes of liver damage in those using illicit substances are discussed.

Hepatotoxicity is not increased in alcoholics with positive urinary cocaine metabolites

Cocaine hepatotoxicity in mice has been reported by numerous investigators. Such hepatotoxicity in other animal models has been more difficult to produce. We prospectively assessed 1212 alcoholics admitted for detoxification for historical, clinical and laboratory evidence of concomitant cocaine/crack use and evidence of liver disease. The 470 cocaine positive subjects had both longer durations and higher average daily costs of cocaine/crack use than the 742 cocaine negative subjects, but had a shorter duration of alcohol use. Serum transaminases were higher in the cocaine negative group. There were no clinically severe cases of liver disease or rhabdomyolysis in either group. Serum hepatitis B surface antibody and hepatitis A antibody were more frequent in the cocaine positive subjects. In conclusion, in this large sample of alcoholics abusing cocaine, severe hepatotoxicity was not at all evident. The previous reports of hepatotoxicity may represent co-morbidity. Some possibilities include infection with a hepatitis or other virus, the presence of an adulterant, an idiosyncratic reaction or an enzymatic abnormality.

Biomechanisms of cocaine-induced hepatocyte injury mediated by the formation of reactive metabolites

Cocaine is an intrinsic hepatotoxin in laboratory animals, and there is growing evidence that high doses of cocaine can precipitate hepatic necrosis in humans. The rodent model of cocaine hepatotoxicity is commensurate with the concept that a multistep mainly cytochrome P-450 dependent N-oxidative pathway is responsible for the expression of hepatocellular injury. Among the possible biomechanisms by which cocaine exerts its cytotoxic effects, direct oxidative damage by reactive oxygen species generated by redox cycling during the metabolic cascade seems most important. The role of the ensuing lipid peroxidation and protein thiol oxidation is less clear. Similarly, the functional role of irreversible (covalent) binding of a not yet defined electrophilic cocaine intermediate to hepatocellular proteins remains enigmatic so long as the critical molecular targets have not been identified. Finally, glutathione plays a pivotal protective role against cocaine-induced hepatic injury. Interactions with ethanol or inducers of the expression of the cytochrome P-450IIB subfamily can potentiate cocaine hepatotoxicity. Thus, the net amount of the ultimate reactive species seems to determine the severity of the hepatic lesions and to be responsible for the marked interspecies, interstrain, and sex differences. Recent advances in culture techniques of hepatocytes and precision-cut liver slices from various species including man have made it possible to correlate cocaine biotransformation with cytotoxicity and to selectively study the putative cellular mechanisms. Clearly, more studies are necessary to further illuminate our understanding of the role of the biochemical and molecular events precipitating hepatic necrosis during cocaine-mediated hepatotoxicity.