Heroin is considered one of the most harmful of all illicit drugs. There are many problems that can result from heroin use, especially if it’s used heavily or regularly.

Heroin is commonly injected, which comes with a range of additional harms associated with the unsanitary sharing of injecting equipment, such as the transmission of blood borne viruses like hepatitis C and HIV.

According to the Australian Institute of Health and Welfare (AIHW), the risk of heroin overdose is high, especially when used in conjunction with other drugs. Of the 1,819 drug-induced deaths in Australia in 2022 (excludes alcohol and tobacco), 487 involved heroin.

Heroin is a central nervous system depressant, meaning that it slows down the brain functions and the control of breathing (which can slow down or even stop). Accidental overdoses are common.

Overdoses can happen if too much heroin is used or if the person also has other drugs in their system (e.g., alcohol, benzodiazepines such as Valium, or other opioids such as morphine and oxycodone). Combining heroin with some kinds of antidepressants and/or stimulant drugs (e.g., cocaine or methamphetamine) also increases the risk of overdose.

Signs of overdose include:

• Extreme drowsiness
• Small (‘pinned’) pupils
• Slowed breathing and heart rate
• Heavy snoring.

Sometimes a person will also experience:

• Blue or purple coloured skin (cyanosis), usually starting on lips and fingers
• Low blood pressure
• A drop in body temperature to below 35° Celsius (hypothermia).

If caught in time, the effects of overdose can be reversed by administering a drug called naloxone.

Mixing heroin with other drugs – including over the counter or prescription medications – can be unpredictable and dangerous, severely reducing the rate of breathing and may cause enormous strain on the heart and kidneys, and increase the risk of overdose.

Opioids, and heroin in particular, have the highest dependence liability of all illicit drugs. There is no sex difference with women as likely to become heroin dependent as men. Injecting opioids is associated with the highest risk of dependence.

Opioid withdrawal syndrome has both physical and psychological symptoms. It is generally characterised as a flu-like illness. Symptoms commence between eight and 12 hours after the cessation of heroin use and typically peak on the third day post-cessation; the syndrome usually resolves after a week.

Signs and symptoms of opioid withdrawal syndrome include:

• Sweating, watery eyes and/or runny nose
• Increased urinary frequency
• Diarrhoea, nausea, vomiting, abdominal cramps
• Muscle spasm resulting in headaches, backaches and leg cramps
• Goosebumps
• Dilated pupils
• Elevated blood pressure, increased heart rate
• Anxiety, irritability, dysphoria
• Sleep disturbances
• Craving for opioids.

Opioids make the largest contribution to illicit drug-related death and carry the highest mortality risk. Mortality is highest among injecting opioid users, reflecting the higher risks for overdose, blood-borne viruses, vascular damage and suicide. The most common cause of premature death is acute drug toxicity – otherwise known as overdosing.

Opioids, including both licit and illicit substances, have been the leading class of drug present in drug-induced deaths in Australia for the last 20 years.

People who use heroin suffer high levels of major depression and anxiety disorders, including post-traumatic stress disorder. Suicide rates among people who use heroin are extremely high and estimated at 14 times that in the general population. They also have high rates of borderline personality disorder and antisocial personality disorder.

One of the more common treatments for heroin dependence is opioid substitution treatment (OST). The evidence demonstrating the effectiveness of OST for heroin dependence is well established.

OST is also called medication-assisted treatment of opioid dependence. The most common medicines used in Australia are methadone, buprenorphine and naltrexone.

Other treatment options include residential rehabilitation, which is a drug-free treatment requiring residence in the treatment agency subsequent to having undertaken detoxification. Programs may be short (approximately one month) or longer (at least three to six months). Counselling and withdrawal-management are also available.

According to the AIHW’s National Drug Strategy Household Survey (NDSHS), heroin use is low among the general population. Around 0.1% of the population, or 30,000 people, had used heroin in in the past 12 months in the 2022-2023 NDSHS.

The Illicit Drug Reporting System (IDRS) is an Australian monitoring system run by the National Drug and Alcohol Research Centre (NDARC) at UNSW Sydney that identifies emerging trends of local and national concern in illicit drug markets.

The Ecstasy and Related Drugs Reporting System (EDRS) is an Australian monitoring system run by NDARC that identifies emerging trends of local and national interest in ecstasy and related drug use, markets and harms.

The Pocket Guide to Drugs and Health is a publication authored by experts from NDARC that provides information for health professionals on the impact of drug use.

The Australian Institute of Health and Welfare collects information on alcohol and tobacco consumption, and illicit drug use among the general population in Australia.

The Australian Bureau of Statistics is Australia’s national statistical agency, providing official statistics on a range of economic, social, population and environmental matters of importance to Australia.

Alcohol and Drug Foundation (2024). Heroin. Retrieved from: adf.org.au/drug-facts/heroin/

Australian Institute of Health and Welfare (2024). Low-prevalence illicit drugs in the NDSHS. AIHW, Australian Government. Retrieved from: aihw.gov.au/reports/illicit-use-of-drugs/low-prevalence-illicit-drugs-ndshs

Australian Institute of Health and Welfare (2024). Alcohol, tobacco & other drugs in Australia. AIHW, Australian Government. Retrieved from: aihw.gov.au/reports/alcohol/alcohol-tobacco-other-drugs-australia/contents/drug-types/illicit-opioids-including-heroin

Darke, S., Lappin, J., & Farrell, M. (2024). The Clinician’s Guide to Illicit Drugs and Health (Revised Edition). London: Silverback Publishing.

Chrzanowska, A., Man, N., Sutherland, R., et al (2024). Trends in overdose and other drug-induced deaths in Australia, 2003-2022. Sydney: National Drug and Alcohol Research Centre, UNSW Sydney. Retrieved from: unsw.edu.au/research/ndarc/resources/trends-drug-induced-deaths-australia-2003-2022

Swift, W., Nielsen, S., Kaye, S., et al (2017). A Quick Guide to Drugs & Alcohol. Third Edition. Drug Info, State Library of New South Wales.