• Activates receptors called mu and delta opioid receptors. 
• These receptors are abundant in brain areas involved in responses to psychoactive substances, such as in the mesolimbic dopamine pathway.

• The effects of heroin can last for approximately 3-5 hours.
• An individual who is coming down from heroin use may feel irritable as the drug leaves their body. 
• They may also feel depressed.

• Heroin is mostly injected into veins (intravenous). 
• It is also smoked, known as “chasing the dragon”, snorted, or added to cannabis or tobacco cigarettes
• Depending on how heroin is taken, the effects may be felt within 7-8 seconds (injecting) or within 10-15 minutes (snorting or smoking).
• The effects of heroin can last for approximately 3-5 hours.

Airways and lungs:

• no breathing
• shallow breathing
• slow and difficult breathing

Eyes, ears, nose, and throat:

• dry mouth
• extremely small pupils, sometimes as small as the head of a pin ("pinpoint pupils")
• tongue discoloration

Heart and blood:

• low blood pressure
• weak pulse

Skin:

• bluish-colored nails and lips

Stomach and intestines:

A high dose of heroin can cause an individual to overdose. This means that an individual has taken more heroin than the body can cope with. 

The risk of overdose increases if the strength or purity of the heroin is not known. Injecting heroin increases the risk of overdose due to large amounts of the drug entering the blood stream and quickly travelling to the brain. 

In addition to the side effects already listed, an individual may experience:

• feelings of intense pleasure
• strong feelings of well-being
• pain relief
• reduces stress and emotional pain
• cough suppression
• controls diarrhoea
• confusion
• constricted pupils
• lowered cough reflex
• reduced sexual urges
• drowsiness
• slurred and slow speech
• reduced coordination
• dry mouth
• decreased heart rate and blood pressure
• slow breathing rate
• nausea and vomiting
• reduced appetite
• strong rituals of sharing drug-using experience

Smack, skag, H, dope, junk, hammer, slow, gear, harry, big harry, horse, black tar, china white, Chinese H, white dynamite, dragon, elephant, homebake, poison.

• Campbell, A. (2001)  The Australian Illicit Drug Guide: Every person’s guide to illicit drugs – their use, effects and history, treatment options and legal penalties, Schwartz Publishing Pty Ltd, Melbourne
• Denning, P., Little, J. & Glickman, A. (2004)  Over the Influence: The Harm Reduction Guide for Managing Drugs and Alcohol.  The Guildford Press, New York, New York.

• diminished psychomotor performance
• dose-related tachychardia (increased heart rate)
• immunosuppression, including decreased white blood cell count
• chronic sinusitis
• chronic pharyngitis
• chronic bronchitis
• abnormality of cells lining respiratory tract
• lung cancer
• shortened attention span
• decreased judgment
• impaired concentration skills
• deterioration in interpersonal relations
• profound short-term memory loss
• attrition of planning, computational and reasoning skills

• diminished psychomotor performance
• reddening of the conjunctiva of the eyes (blood shot eyes)
• dry mouth/dry eyes
• sinusitis
• pharyngitis (throat inflammation)
• bronchitis
• anxiety
• paranoia
• panic
• depression
• dysphoria
• depersonalisation
• hallucinations
• reduced ability to concentrate
• tiredness
• confusion