Since meth contains hydrochloride salt which is soluble in water, meth can be injected directly into the veins with a needle and syringe. (street name the "works.") When you inject meth, it's possible to ingest a great deal of the drug in a single IV. (Anything from a small street dose or "point" of 100 mg. to over a gram.) Since most meth users have built up a considerable tolerance for the drug by the time they're injecting, an injected dose of a gram could be potentially fatal for someone with lower tolerance.
Injecting meth provides the highest blood levels of drug in the shortest amount of time. Upon injection, the meth reaches the brain in a matter of seconds, inducing an intense rush lasting 5 or 10 seconds. The meth high that follows can last 6 to 24 hours.
Injecting meth 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 and practice unsafe sexual activities. Because meth use usually increases sexual arousal while simultaneously reducing the person’s ability to make healthy choices, a person injecting meth may share needles and/or practice unsafe sexual activity making them prone to deadly diseases such as HIV/AIDS and hepatitis. 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.