Some of the most addictive substances on the planet.
Opioids, including heroin, morphine, oxycodone, fentanyl, and more, are commonly used around the world — the National Institute on Drug Abuse reports that an estimated 26.4 to 36 million people abuse opioids worldwide.
The number of people who abuse the drugs is on the rise, with the rate of unintentional overdose deaths from prescription pain relievers more than quadrupling since 1999. Also, heroin was ranked as the most addictive substance in the world by a panel of neuropsychopharmacologists.
Here’s what goes on in the brain and body while under the influence of opioids.
1. Opioids attach to opioid receptors in the body
Opioid receptors can be found in the brain, spinal cord, gastrointestinal tract, and other organs in the body, and opioids act by attaching to them.
2. The perception of pain is reduced
Once the drugs have attached to the opioid receptors, they reduce the user’s perception of pain. Opioids are commonly prescribed following painful dental procedures or for injury-related pain.
3. A surge of euphoria occurs
Opioids can be taken in a number of ways, and when it comes to heroin, users report the most intense high from shooting the drug intravenously. Once it’s been injected, the drug travels through the bloodstream into the brain, giving the user a surge of euphoria. To produce this rush, the drug acts on the brain’s limbic system, which is involved in regulating emotions and feelings of pleasure.
4. Mental function is clouded
Along with the surge of euphoria, users commonly experience dry mouth, a warm flushing of the skin, and clouded mental functioning, NIDA reports.
5. Analgesic effect in the spinal cord
Opioids block pain messages from being sent between neurons, which produces an analgesic (pain-relieving) effect in the spinal cord, according to an infographic on Scholastic.
6. Dopamine is released
After the opioid receptors are activated in the reward center of the brain, they stimulate the release of dopamine, a neurotransmitter that’s associated with the brain’s pleasure system.
7. Depending on the drug’s half-life, the high can last anywhere from 15 minutes to 6 hours
Although drugs like heroin and morphine are in the same drug class, their effects on the brain and body last for different amounts of time. Heroin’s half-life is 15 to 30 minutes, producing an intense but fleeting high, while morphine’s half-life lasts from four to six hours.
8. There’s the chance for some unpleasant side effects
Aside from the feelings of euphoria and relaxation, opioids can also come with some unwanted side effects — drowsiness, nausea, and constipation.
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