What substance is associated with the risk of intracranial hemorrhage or myocardial infarction in addicts?

Cocaine is known to significantly increase the risk of both intracranial hemorrhage and myocardial infarction among users. The mechanism behind this involves cocaine's potent sympathomimetic effects, which can lead to vasoconstriction and increased blood pressure. As a result, the risk of strokes and heart attacks is elevated due to the stress placed on the cardiovascular system. Additionally, cocaine can cause arrhythmias, further raising the likelihood of cardiac events.

While other substances listed have their own health risks, they do not have the same level of association with these specific serious conditions. Heroin is more commonly linked to respiratory depression and overdose; alcohol can lead to liver disease and other health issues but does not present the same immediate risks of hemorrhage or cardiac events as cocaine. Marijuana has a different risk profile and is not typically associated with these severe acute cardiovascular complications. Thus, cocaine stands out as the substance most closely tied to these specific risks.