‘The Great Equaliser’, heroin has gained a reputation for its’ ‘hold’ over addicts, and notoriety for the ease of becoming an addict to it.
A derivative of the opium poppy, which has been cultivated in Mesopotamia (Iraq) for thousands of years, heroin was originally prescribed as a cough suppressant and as an alternative to the already available Morphine. Ironically, medical practitioners at the time believed that morphine was too addictive, and wanted a replacement. Now, of course, morphine is prescribed to help people beat an addiction to heroin.
Heroin is a depressant. Its most common side effect is a depression of the respiratory system which can be so high as to kill the user. Continued use of heroin, and the altering effect on the Mesolimbic Pathway in the brain, the ‘reward centre’, ultimately leads to addiction. Risks to users are numerous, including; infection from needle swapping (including bloodborne pathogens), fungal infections and decreased kidney function, as well as the problems associated with addiction itself.
Heroin on Wikipedia.