Heroin Effects on the Body

Heroin is an opioid drug that is made from a naturally-occurring form of morphine found within the seeds of an opium poppy plant.1 It is a psychoactive substance that alters brain function, affecting one’s moods, consciousness and perceptions. It also has a wide range of effects on the rest of the body.

The chemical structure of heroin is similar to that of endorphins – or naturally occurring opioid chemicals produced by your body’s central nervous system (CNS).2 The primary function of endorphins is to block the transmission of pain signals along sensory neurons and to produce pleasurable sensations of euphoria.

The onset of heroin’s effects largely depends on the method that the drug is administered, as the method affects how fast the drug is able to cross over the blood-brain barrier and reach the brain.3,4 The blood-brain barrier is a neurovascular unit in the brain made up of many different cells that together act as a physical barrier to the brain. Once heroin traverses this barrier and enters the brain,

it undergoes several chemical reactions before ultimately being converted back into morphine. The opioid drug then binds rapidly to the opioid receptors within the brain. This binding action initiates a cascasde of molecular events and is what leads to pleasurable sensations of euphoria, relief from pain and diminished anxiety – all characteristics of the heroin high.

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Immediate Effects of Heroin Use on the Body

The heroin high is characterized by an immediate and intense rush of pleasure and euphoria.3,4 It can also be accompanied by additional sensations, including:

  • Relief from pain.
  • Alleviation of anxiety.
  • Overall sense of wellbeing.
  • Warm flushing of the skin.
  • Sensation of heaviness within the extremities.

  • Dry mouth.
  • Increase in body temperature.
  • Nausea.
  • Vomiting.
  • Severe itching.

The duration of these effects from a heroin high can also vary somewhat, depending on how the drug was administered.3,4

During this “rush,” some describe feeling a warmth traveling through the body and extremities.

In general, the more immediate and intense sensations of euphoria that occur with heroin use last anywhere from 45 seconds to several minutes.4 This period is then followed by what is known as the “rush” or “hit,” which is anywhere from 10 to 20 minutes long.

Once the rush of the heroin high wears off, the body begins to feel heavy, and the individual may be overwhelmed with feelings of drowsiness.4 This last phase of the high can last for several hours and is marked by other symptoms, including:

  • Clouded mental functioning.
  • Periods of slipping in and out of consciousness known as “nodding off” (most evident very shortly after the pleasurable euphoria has dispersed).
  • Confusion.
  • Slowed heart rate.
  • Irregular heart rate.
  • Suppressed breathing.

The effects of this final stage of the heroin high can be potentially life-threatening. In particular, slowed breathing can reduce the amount of oxygen that is able to reach the brain.3,4 This condition is known as “hypoxia” and may lead to coma, permanent brain damage and even death.

Long-term Heroin Effects

Heroin use is associated with a high risk of becoming both physically and psychologically dependent on the drug. Indeed, getting high from heroin is an intensely pleasurable experience and it can be used to provide relief from both physical aches and pains, as well as psychological distress.5 Moreover, the drug’s effectiveness

in relieving these symptoms is felt almost immediately in some cases, which further reinforces its use. Over time and with repeated use, however, the body begins to function as if it no longer needs to make its own chemicals for pleasure or pain relief, and the user is left physically dependent on taking the drug in order to feel relief.

Physical dependence on heroin leads to symptoms of discomfort and pain when the drug is removed from the body.

This dependency experience is known as withdrawal. Experiencing this phenomenon is often a telltale sign of a substance abuse disorder.

The onset of these troubling set of symptoms frequently motivates individuals to continue using in an attempt to relieve them.

Though the experience of withdrawal varies widely from person to person, individuals who are addicted to using heroin can typically begin to experience unpleasant withdrawal symptoms within 10 hours of last using the drug.Common symptoms of withdrawal from heroin include:

  • Agitation.
  • Anxiety.
  • Watery eyes.
  • Runny nose.
  • Sweating.

  • Pupil dilation
  • Diarrhea.
  • Stomach cramps.
  • Muscle cramps and spasms.
  • Fever and chills.

There has been some evidence to suggest that repeated heroin use can lead to permanent alterations within the brain.4,6

Chronic heroin use has been associated with deteriorations in white matter in the brain – which may lead to impairments in decision-making, self-regulation and the ability to respond to stress.4

Profound degrees of tolerance and physical dependence are also significant long-term risks that accompany heroin use.6,7 

Over time, heroin use also leads to other long-term deteriorations in physical health. Some of the most common health problems associated with heroin addiction are listed below2,4:

  • Heart problems.
  • Liver disease.
  • Chronic insomnia.
  • Lung problems (including tuberculosis and pneumonia).
  • Permanent damage to nasal soft tissue.

  • Collapsed veins.
  • Heart valve abscess.
  • Weight loss.
  • Chronic constipation.
  • Sexual dysfunction (in men).
  • Irregular menstrual cycle (in women).

Indirect Effects of Heroin Use

Syringe exchange programs across the U.S. aim to reduce infections from needle-sharing.

In many cases, heroin addiction tends to be accompanied by lifestyle choices that are also unhealthy: recreational drugs, cigarette smoking, lack of exercise and poor nutritional habits.3

Heroin’s effects on the body are only worsened when the user also makes these additional risky health and behavioral choices.

By sharing syringes and other paraphernalia used for injecting the drug, heroin addicts have higher risk of developing infections through contact with infected blood. Examples of these deadly viral diseases that can spread by needle-sharing include HIV, hepatitis B and hepatitis C.2

Learn More About Addiction and Get Help

Taking the first steps to help yourself or a loved one can feel intimidating. If you or someone you love may be suffering from an addiction to heroin, however, there are many ways to get help. One important

first step is educating yourself about heroin, about addiction and about treatment options that are available to you. Call to speak with one of our recovery advisors and find the help you need.

Learn About Your Options for Help

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  1. Hughes PH, Barker NW, Crawford GA, Jaffe JH. The natural history of a heroin epidemic. Am J Public Health 1972;62(7):995-1001.
  2. Heroin. National Institute on Drug Abuse.
  3. The Dangers of Heroin. Drugs-Forum.com.
  4. Zacny JP. A review of the effects of opioids on psychomotor and cognitive functioning in humans. Ex Clin Psychopharmacol 1995;3(4):432-466.
  5. Drugs of Abuse. U.S. Department of Justice Drug Enforcement Agency.
  6. Rook EJ, van Ree JM, van den Brink W, Hillebrand MJ, Huitema AD, Hendriks VM, Beijnen JH. Pharmacokinetics and pharmacodynamics of high doses of pharmaceutically prepared heroin, by intravenous or by inhalation route in opioid-dependent patients. Basic Clin Pharmacol Toxicol 2006;98(1):86-96.
  7. Stephens RC. The street addict role: A theory of heroin addiction. 1991 Suny Press. Albany, NY.

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