Short term effects
 

Heroin is either smoked, or dissolved in water and injected. When smoked, it is heated on tin foil and the fumes are inhaled through a small tube. Injecting creates a more powerful 'high'. Most people get a 'rush' or 'buzz' after the first few minutes of taking heroin.Users feel drowsy, warm, content and have a general sense of well-being. Heroin also detaches the user from feelings of pain and worry. First time use (especially if injected) often causes nausea, vomiting and severe headaches. With extended use, tolerance levels build up so a greater amount is needed to create the same 'high'. Smoking heroin is a common form of taking the drug, but users tend to switch to injection for a more immediate and powerful 'rush' and a more efficient way of utilising the drug. People can become dependent on heroin through smoking the drug in the same way as they can through injecting it. Injection carries risks of infection e.g. hepatitis and HIV from contaminated needles, syringes and other injection equipment. To avoid dangerous infections, users should always use clean, sterilised needles and syringes and never share injecting equipment with other users.
 

Heroin users risk overdosing. This is because heroin is generally obtained from illicit sources and therefore the dose taken is unpredictable and may be dangerously adulterated. An overdose can cause rapid heartbeat, heart failure, shortness of breath and ringing in the ears or head, unconsciousness or coma. When unconscious there is a danger that the user may choke on their vomit.
 

Heroin has been known to cause unexplained sudden death. Users have been found dead with a needle in their arm suggesting that they died very rapidly. This may be due to an idiosyncratic reaction either to the drug, the injection or impurities present in the drug.
 

Long term effects

Regular users find that they need to take more to try and achieve the feelings of euphoria which they experienced in the early stages of their habit. Users who form a 'habit' may eventually take heroin just to feel 'normal'. At this stage the user will almost certainly be injecting heroin, as opposed to smoking it. A long-term heroin user may find that veins used for injection collapse, and therefore, they have to find new veins to inject. Protracted use also causes extreme constipation and a loss of appetite. This can cause malnutrition in addicts firstly because they are never hungry, and secondly because constipation can become so painful that they do not want to eat food.
 

Circumstances surrounding the use of heroin can lead to mental health problems. Addiction often leads to depression and suicide. Heroin addicts can become involved in crime, prostitution and drug dealing because of the expense of taking heroin on a daily basis. Holding down a job is particularly difficult because users often find it difficult to concentrate or to adapt to a regular schedule. However, physical dependence on heroin is not inevitable, and some people do take heroin on an occasional basis.
 

Also, pregnant women who use heroin risk giving birth to smaller babies who are addicted to heroin. The baby will experience withdrawal symptoms after birth.
 

Withdrawal symptoms can occur after several weeks of use. Withdrawal begins between eight and 24 hours after the last 'fix' of heroin. Symptoms are aches, tremors, sweating, chills, muscular spasms, yawning and sneezing. These fade after seven to 10 days but users often do not regain a natural feeling of well-being until several months after coming off heroin.
 

The long-term physical effects of pure heroin are not usually serious but problems can occur with the respiratory system. Constipation and menstrual irregularity are not uncommon. Chronic sedation can occur in heavy, long term users.