Effects of cocaine misuse

Cocaine has a very high addiction rate, accounting for 10 per cent of all deaths secondary to illicit drug use in Australia, with the lifetime use of cocaine rising from 3% in 1991 to 4.5 per cent in 1998.

Cocaine misuse is associated with acute myocardial infarction (AMI) and in men who are relatively young, fit and healthy, and who have minimal, if any, risk factors for cardiovascular disease.

In the United States, about 25 per cent of AMIs in people aged 18-45 years were attributable to frequent cocaine use.

Professor Tennant said the effects of cocaine induce an increase in heart rate and blood pressure, leading to a resultant increase in oxygen demand by the heart.

"The risk of having an AMI secondary to cocaine use is maximal in the first hour after ingestion," Professor Tennant said.

"Long-term use may cause repetitive episodes of heart spasm, and this may cause endothelial damage and subsequent acceleration of cardiovascular disease.

Chronic intake of cocaine depletes dopamine, leading to the intense depression described by addicts. This depletion triggers a cycle of craving for cocaine and temporary relief of depression by further cocaine ingestion.

Increased cocaine misuse results in higher demand on emergency departments and hospital admissions, and higher rates of mortality.

The authors suggest prevention by behaviour modification through public awareness and education campaigns, which may reduce cardiovascular and other morbidity associated with cocaine use, as well as the need for further research to counterbalance the limited patient samples and limited experimental doses of cocaine used in past research.

The Medical Journal of Australia is a publication of the Australian Medical Association.

CONTACT: Christopher Tennant (02) 9926 7746 (B/H); (02) 9436 3890 (A/H)

Sarah Crichton, AMA (0419) 440 076