Though illegal, heroin affects the body the same way other opioids do, including prescription medications. When heroin enters the body, the drug activates receptors in the brain called mu-opioid receptors (MORs). Brain chemicals called neurotransmitters bind to these receptors to regulate pain, release hormones, and increase feelings of well-being. When heroin activates receptors in the brain’s reward center, the drug stimulates the release of dopamine, causing users to feel good.
While dopamine makes users temporarily feel better, the neurotransmitter also unintentionally works against them. In addition to producing feelings of pleasure, dopamine blurs the difference between the expected reward and the reward actually received. Because of this, dopamine reinforces the behavior that caused a particular reward. In short, excessive amounts of dopamine encourages users to continue using heroin. The more they use heroin, the more the drug affects their body.
At first, heroin causes an intense, pleasurable sensation known as a “rush.” Usually, the intensity of the rush depends on how quickly heroin enters the brain and binds to the opioid receptors. The euphoria produced by the rush is usually accompanied by a warm flushing of the skin, dry mouth, and heavy-feeling hands, arms, and legs. But the rush doesn’t last long. Not long after heroin’s initial effects end, drowsiness and other adverse effects begin.
Repeated heroin use can change the physical structure of the brain and the way the organ functions. When this happens, neural and hormonal imbalances can affect cognitive and executive functioning. Some studies have even shown that prolonged use of heroin can actually deteriorate the brain’s white matter. Losing large amounts of white matter can negatively impact users’ ability to reason, make decisions, and think logically. A decreased amount of white matter in the brain can also make regulating behavior and dealing with stress difficult.
Overdose is one of the main consequences of heroin abuse. In 2019, more than 14,000 people in the United States died from drug overdoses involving heroin. After users experience heroin’s initial effects, the drug heats up their body, dehydrates their system, and slows their breathing and heart rate. Heroin overdose can happen when users consume an excessive amount of the drug in a short period of time or mix heroin with prescription medicines, other drugs, or alcohol. Individuals who have overdosed on heroin should be treated by medical personnel immediately or given naloxone, a medicine that blocks the effects of the drug.
Another consequence of heroin abuse is an increased risk of HIV, AIDS, and Hepatitis B and C. This risk is especially true for individuals who use needles to inject the drug into their veins or muscles. Sharing needles and other drug injection equipment can easily increase individuals’ risk of exposure to various diseases and infections. But individuals who smoke or snort heroin may also have an increased risk of contracting HIV/AIDS because they’re more likely to have unprotected sex while under the influence of the drug.
Women who abuse heroin can face challenges during pregnancy. Since the drug passes from the mother to the fetus through the placenta, the unborn child becomes dependent on the drug. When this happens, the child can develop neonatal abstinence syndrome (NAS), a group of problems that occur to newborns exposed to opioid drugs in their mother’s womb.
A large portion of heroin bought on the street contains other substances. Heroin is mixed with other common opioid substances it becomes a dangerous opioid that’s 50 to 100 times more potent than morphine. Street dealers combine other drugs with heroin to save money. Unfortunately, the combination of the these drugs can be deadly. Heroin and other drugs can clog the blood vessels leading to the lungs, liver, kidney, or brain, which can cause permanent damage to the organs.
Using heroin can also result in tolerance and dependence. Tolerance happens when the body is consistently exposed to an addictive substance. When users develop a tolerance for heroin, the current dosage of the drug they consume doesn’t produce the same effects it once did. In other words, the individual’s body has become accustomed to a certain amount of heroin. In order to continue to feel the heroin’s effects, the individual has to consume more heroin, which can lead to dependence.
Dependence is different from tolerance. When individuals become dependent on heroin, their body operates as though they need the drug to function normally. When they don’t have heroin or suddenly decrease the amount of the drug they use, the body functions abnormally and triggers symptoms of withdrawal. When left untreated, tolerance and dependence can lead to addiction.
