Heroin is an opiate made from the chemical morphine, which is extracted from the dried latex of the opium poppy. Morphine is extracted from the opium latex, and these chemicals are used to make opiates, such as heroin, diamorphine and methadone. Heroin is the 3,6-diacetyl derivative of morphine (hence diacetylmorphine) and is synthesised from it by acetylation. The name heroin comes from 'heroisch', the German word for hero. Heroin was originally sold as a painkiller in the 19th century, by the chemical company Bayer, until doctors realised its highly addictive quality. Bayer was even marketed heroin as a "cure" for morphine addiction and cough medicine for children. It is now known that heroin, along with most opiates are converted by the human liver into the morphine with varying degrees of concentration in the blood stream. Pure heroin is a white powder, but street heroin comes as a brownish-white powder that can be smoked, snorted or dissolved and injected. Most of the heroin that is smuggled into the UK comes from Afghanistan.

Heroin is extremely fast acting, and within a few seconds a small dose will give the user an instant feeling of well-being. Once in the brain, heroin is rapidly metabolized into morphine by removal of the acetyl groups. It is the morphine molecule that then binds with opioid receptors and produces the subjective effects of the heroin high. Heroin is therefore a prodrug. Much larger doses can make users relaxed and drowsy. Heroin use also causes lack of concentration, suppresses pain, and sometimes induces anxiety and fear. Physical effects can include blurred vision, constricted pupils, sweating, slow breathing, as well as nausea and vomiting.

Heroin is a very addictive drug, both physically and psychologically, and large doses can lead to stupor and also coma and, in some cases, it can also lead to death. Because it is so addictive, users may find themselves taking more and more heroin just to feel normal, and according to government findings, users spend, on average, £10,000 a year to fund their habit.

The purity of street heroin can also vary quite widely, as the drug can be mixed with other white powders, such as chalk, flour, talcum powder and caffeine. The impurity of the drug means it's often difficult to gauge the strength of the dosage, which runs the risk of overdose.

Heroin is generally injected, which can cause very serious damage to the veins and also puts the user at risk of infection from HIV, hepatitis and other diseases transmitted via used needles.

In the first few hours after the last dose, users will suffer aches, hot and cold sweats, sneezing and spasms which peak after about three days and fade away after about ten days. However, fatigue and weakness may last for several months. The main treatment for heroin addiction is prescribed methadone, which is a synthetically created opiate. There are also problems with methadone, as it is still a highly addictive drug, and it has to be strictly controlled for those wanting to kick the habit.

Heroin is a Class A drug under the Misuse of Drugs Act, which means it is illegal to be in possession of, or supply heroin. The maximum penalty for possession is seven years imprisonment, and a supplier will receive a maximum sentence of life imprisonment.

Formal Chemical Name (IUPAC)
7,8-didehydro-4,5-epoxy-17-methylmorphinan-3,6-diol diacetate

References

http://en.wikipedia.org/wiki/Heroin