Using Heroin: What are the Short Term and Long Term Effects?

The opioid epidemic in America has brought heroin to center stage as overdoses, arrests, and addiction have moved out of the cities and into the more affluent suburbs. Setting aside the external issues of heroin use, there can be serious health repercussions for using this drug. Here we will take a look at both the short-term and the long-term effects of heroin use.

Related Articles: Heroin Withdrawal Guide | Dangers of Heroin Abuse | Heroin Addiction Rehab in Georgia | What Happens When You Use Heroin?

Overview of Heroin Effects

Heroin acts as a powerful central and peripheral nervous system depressant and painkiller. Depending on the route taken, heroin can have different strengths and duration. For example, when eating or snorting heroin it will be broken down completely into morphine through first-pass metabolism and will not produce the same intensity of euphoria typically associated with heroin use. Heroin itself is biologically inactive, and it’s only once the body metabolizes heroin that it produces any effect.

To get an idea of what makes heroin so potent, let’s look at the proper name of heroin for some insight: di (2) acetyl (methyl/carbonyl group) morphine (primary drug). This simply means that heroin is morphine with 2 added acetyl groups. Acetylation is commonly used in organic chemistry to enhance the delivery of a drug across the blood-brain barrier and these acetyl groups allow a large amount of heroin to get into the brain very quickly. When heroin is injected, it is able to enter the brain before breaking down, which allows it to metabolize inside the brain. Once metabolized in the brain, heroin breaks down into the active drugs morphine and 6-monoacetylmorphine (6-MAM), which are the ones responsible for the high and euphoria that heroin produces. 1, 2

Short-Term Effects of Heroin Use

Because of the speed heroin can enter the brain there will be a surge of morphine delivered in a single dose and massive activation of the opioid receptors in the brain. This is much more powerful than taking morphine alone and produces an intense rush of euphoria, relaxation, pain reduction, and a sense of wellbeing.

When injecting heroin, the effects felt are almost immediate. Some of the direct physical symptoms that are produced include:

  • Slowed Heart Rate
  • Depressed Breathing
  • Constricted Pupils
  • Hoarse Voice (due to dry mouth and throat)
  • Pale or Grey Skin
  • Nodding Off (brief lapses in consciousness)
  • Clouded or Slow Thinking
  • Itchiness
  • Decreased Appetite
  • Vomiting (some people vomit regularly when using heroin, while others rarely vomit)

Someone who has recently used heroin may also be easily agitated or irritable. Someone will also appear very tired, or as if they are thinking and moving in slow motion. They may also “nod off” while sitting, talking, standing, or in the middle of performing a simple task. They may awaken after a second or they may slowly relax until they jolt themselves awake by losing their balance. When heroin is injected these effects may last from an hour or two and will slowly wear off over the next few hours.

Short and Long Term Effects of Heroin

Long-Term Effects of Heroin Use

One of the more dangerous effects of long term heroin use is the buildup of tolerance. This means that the brain and body have adapted to the presence of heroin through a process called downregulation, and more heroin is needed to produce the same effects. This begins to happen very early in the stages of heroin use and only escalates as more heroin is used. The development of tolerance also means that someone will feel increasingly uncomfortable without heroin. It is possible that after using heroin for long enough, a user’s body may never return to the tolerance levels they had before using heroin. This means that any opioid painkillers that they may need for serious pain issues will be less effective.

Some of the more long-term effects of heroin use will take at least several weeks of regular use to appear. These issues have a wide range of severity and include simple discomfort, danger, and some may ever be fatal. Just a few of the long-term effects of heroin use may include:

  • Chronic Constipation: This is unpleasant on its own and may lead to rectal prolapse, impacted stool, and other gastrointestinal issues.
  • Tooth Decay: Due to chronic dry mouth as well as decreased focus on personal hygiene.
  • Reproductive Dysfunction: In men, heroin can interfere with the ability to orgasm, and in women, it may cause menstrual abnormalities.
  • Malnutrition: Chronic low appetite can lead to a host of other issues caused by malnutrition.
  • Insomnia: While “nodding off” is common, actual REM and deep sleep can become difficult after prolonged heroin use.
  • Compromised Immune System: Due to malnutrition, decreased metabolism, and repeated injection wounds.
  • Respiratory Disease: People who use heroin are known to suffer a higher incidence of lung-related health issues such as pneumonia.
  • Decreased Ability to Manage Pain: Due to tolerance, other painkillers won’t work as well if and when they are needed for injuries or surgery.
  • Increased Anxiety: After prolonged heroin use, it is not uncommon for someone to have difficulty managing their anxiety levels.
  • Increased Depression: Heroin use often becomes the main objective in someone’s life, and there is usually very little motivation for anything else.
  • Increased Risk of Organ Damage: IV drug use poses unique risks for many organs such as the heart, lungs, kidney, liver, and brain.


  1. British Journal of Pharmacology: Levels of Heroin and Its Metabolites in Blood and Brain Extracellular Fluid After I.V. Heroin Administration to Freely Moving Rats
  2. Basic & Clinical Pharmacology & Toxicology: Pharmacokinetics and Pharmacodynamics of High Doses of Pharmaceutically Prepared Heroin, by Intravenous or by Inhalation Route in Opioid-Dependent Patients

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