Street names: diamorphine, black tar, brown sugar, dope, hezza, horse, skag, dust, smack, junk, H, big H, hell dust, nose drops, thunder, China white
Heroin is an illegal drug that is synthesized from morphine, which in turn is derived from opium, the juice that is secreted by seeds of the poppy plant.
Use of heroin in Canada was first prohibited when the country's first narcotic drug regulation, The Opium Act, was introduced in 1908 to regulate opium produced, sold or possessed for non-medical reasons. The illegal drug is now governed by the Controlled Drugs and Substances Act (CDSA), where it is listed as a controlled substance under Schedule 1, which contains the most dangerous drugs.
Heroin is often "cut" with other additives, which can change its appearance and reduce its purity. As with all illegal drugs, the manufacturing process and other chemicals used to produce the drug can vary significantly.
CAMH reports that the purity of heroin sold on the street can range anywhere from two to 98 per cent. In May 2013 the RCMP warned the public after two men died after being sold drugs that they believed to be heroin, but were actually Fentanyl.
Heroin can be dissolved in water and injected directly into a vein or under the muscle or skin. It can also be smoked or snorted.
The purest forms of heroin are a white powder. As the drug is mixed with other substances its texture and colour can change, with less pure forms having colouration that can range from beige to brown depending on what other substance has been "cut" with. There is also a dark brown or black version of the drug that has a tar-like feel.
The body has opioid receptors in the brain, spinal cord and some internal organs. When an opioid like heroin is taken it activates these receptors, which create a euphoric feeling and analgesic effect, where physical pain is significantly reduced or not felt at all.
Heroin users will typically feel a brief rush, followed by a feeling of tranquility that lasts for up to an hour that is known as being "on the nod."
The initial rush is most intense when heroin is injected into a vein and will typically be felt within a few seconds and last from 45 seconds to a few minutes. (Heroin injected under the skin takes longer to take effect.) When smoked or snorted the feeling is not as strong and the effects are typically felt within 10 t0 15 minutes. While on the nod the person will alternate between a wakeful and drowsy state, where breathing slows down and there is the possibility of respiratory failure.
Whether injected, snorted of smoked the effects of heroin typically last for three to five hours, depending on the dose.
Heroin's short-term effects include a suppression of pain and a feeling of euphoria followed by a sense of tranquility. Negative effects include nausea, vomiting, itching, sweating, slower breathing, pinpoint pupils, dizziness, constipation, headaches, confusion and a lack of emotion.
Chronic use of the drug can lead to collapsed veins, abscesses, liver disease, infection of the heart lining and valves, decreased libido, missed periods in women, breathing difficulties and even change a person's gene expression and brain plasticity.
Overdose is a serious risk when heroin is used, with the purity of the drug, use by injection or the use of heroin with another drug being three of the biggest risk factors. Signs of overdose, which is extremely dangerous, include a bluish tinge to person's the lips and nails, stomach spasms, constipation, a dry nose/ears/mouth, tongue discolouration, extremely small pupils, a weak pulse and shallow breathing, difficulty breathing or no breathing. Medical help must be sought immediately.
Heroin is highly addictive, both psychologically and physically, and users can develop an addiction within several weeks of regular use. A tolerance to the drug can also develop with regular use, which leads to higher use of the drug. Once a person is addicted, the drug must be used every six to 12 hours to avoid withdrawal symptoms.
Addiction can be treated effectively with Methadone or Suboxone maintenance, which prevents heroin withdrawal and reduces cravings.
Drug policy of Canada http://en.wikipedia.org/wiki/Drug_policy_of_Canada
 Update – Public Health Warning http://bc.cb.rcmp-grc.gc.ca/ViewPage.action?siteNodeId=50&languageId=1&contentId=30281
Heroin Addiction Warps Brain's Ability to Change http://www.medpagetoday.com/MeetingCoverage/SFN/42901