Injecting cocaine provides the highest blood levels of drug in the shortest amount of time. Upon injection, the cocaine reaches the brain in a matter of seconds, and the exhilarating rush that follows can be so intense that it induces some users to vomit uncontrollably. The euphoria passes quickly and is followed by a strong desire to do more of the drug.
Injecting cocaine can end up being a very frequent activity because of the addicting nature of the rush and the short duration of the high. Also, because pain is deadened around the injecting site (cocaine is a local anesthetic), veins become damaged very quickly.
Injecting cocaine increases the risks for infections at the injection site, and certain deadly diseases like HIV/AIDS and hepatitis. These diseases often occur in people who share needles. Because cocaine use and addiction reduces a person’s ability to make healthy choices, a person injecting cocaine may share needles to if they are craving the drug. HIV/AIDS causes a person's immune system to stop working properly, which is fatal. Hepatitis affects a person's liver, which can cause cancer and death, as well as long term health problems.
Cocaine is sometimes injected concurrently with heroin. Injecting cocaine and heroin together is commonly referred to as "speed balling" Cocaine can temporarily mask the downer effects of heroin and other ‘downer-type’ drugs as well as mask the symptoms of overdose creating a very dangerous combination.