Heroin is one of a group of drugs known as opiates (sometimes called narcotic analgesics). Other opiates include opium, morphine, codeine, pethidine and methadone. Heroin and other opiates are depressants. They slow the central nervous system’s activity and messages going to and from the brain and the body. This includes physical, mental and emotional responses.

Heroin has various street names – smack, skag, dope, H, junk, hammer, slow, gear, harry, piss, shit and horse among them.

Opium takes its name from the opium poppy, which grows in many parts of the world – commonly in Asia and the Middle East, but also in the United States and Australia. When the seedpod of the poppy is cut, a sticky resin oozes out (opium). Opium is refined to produce the natural painkillers morphine and codeine.

For centuries many cultures have used opium as a medicine and as a recreational drug. Morphine, codeine and pethidine are still widely used for medical purposes.

In the last century, powerful painkillers have been produced in the laboratory. These drugs have similar effects to the natural opiates.

Heroin is made from morphine or codeine by a chemical process but has a stronger painkilling effect than the drugs from which it is made. It comes as white to off-white granules or pieces of “rock” with a bitter taste, but no smell. It is packaged in foils (aluminium foil) or coloured small balloons.

It is most commonly injected into a vein. It can also be smoked (“chasing the dragon”) or snorted.

The effects of heroin might last three to four hours. The immediate effects include intense pleasure, pain relief, slower breathing and pulse-rate, lower blood pressure, dry mouth, drowsiness, nausea, and vomiting. Bigger quantities impair concentration, can induce sleep, make breathing shallower and slower, can cause sweating, itching, and increased urination.

Too much can cause death. Breathing becomes very slow, body temperature drops, and heartbeat becomes irregular. Users might overdose if too much heroin is injected or it is a strong batch, or if heroin is used with alcohol or sedatives. Most overdoses are a result of heroin with another drug. After an overdose, it is strongly advisable to seek assessment at a hospital.

Illicit drugs such as heroin often lead to complicated health problems. Some of these problems are more likely if the drug is injected: for example, skin, heart, and lung infections and diseases such as hepatitis and HIV.

In its pure form, heroin is relatively non-toxic to the body, causing little damage to body tissue and other organs. But it is highly addictive and regular users are very likely to become dependent on it, even after a few days. Some long-term effects include constipation, menstrual irregularity and infertility in women, and loss of sex drive in men.

Impure heroin: Street heroin is usually a mixture of pure heroin and other substances, such as caffeine and sugar. Additives can be very poisonous. They can cause collapsed veins, tetanus, abscesses and damage to the heart, lungs, liver and brain. Because the users don’t know the purity, and as a consequence the amount to take, it is easy to accidentally overdose and even die.

Dependence can be psychological, physical, or both. Maintaining the “habit” can sometimes lead to users turning to crime to get enough money to pay for it.