Opioids

20.02.2021 |

Episode #9 of the course Introduction to drugs and behavior by Dr. Daniel McGrath

 

If the 1980s was the decade of cocaine, then the 1990s was unmistakably the decade of heroin. The early 90s was the era of grunge music and the Seattle scene. The popularity of grunge also coincided with a surge in heroin use. Sadly, extensive drug use in the grunge scene led to the heroin-related deaths of numerous famous musicians at the time. Furthermore, others continued to use heroin for many years later. Today, we are in the midst of a raging and incredibly destructive opioid epidemic. While heroin is playing a role, newer synthetic opioids such as fentanyl are driving the majority of opioid overdoses and deaths. In this lesson, we are going to examine both heroin and the newer synthetic opioids.

The term opioids is an umbrella label for all-natural and synthetic drugs in this class. In comparison, the term opiates refers to drugs that are naturally derived from the sap of the opium poppy, called Papaver somniferum. From this sap, morphine can be extracted and is a commonly used pain medication around the globe. Heroin is a semi-synthetic opiate created by chemically altering morphine, adding other ingredients, and cooking the mixture. It was initially created by a pharmaceutical company in the late 1890s as a pain reliever but was removed from the market after the dependence potential of the drug was recognized. Other examples of opiates derived from morphine include oxycodone, hydrocodone, and hydromorphone. These are prescription medications but have also been linked to abuse and addiction.

Synthetic opioids are entirely created in a lab. Of these, fentanyl has received the most focus for its role in the opioid epidemic. Initially, it was created over 50 years ago for post-operative pain. It is estimated that fentanyl is up to 100 times more potent than morphine. Unfortunately, fentanyl is relatively easy to manufacture, and the street version is usually created in clandestine labs. The drug can be smoked, injected, snorted, or even swallowed. According to the National Institute on Drug Abuse, fentanyl is responsible for approximately 60% of opioid overdose deaths in the United States.

In the 1970s, scientists uncovered the inner workings of the endogenous opioid system. Within this system, there are three types of opioid receptors: mu, kappa, and delta. When experiencing stress or pain, the body produces neurotransmitters called endorphins. Specific types of endorphins then bind to these receptors. In doing so, the body can naturally relieve pain. However, exogenous opioids also bind to these receptors, especially mu receptors. As a result, opioids also help to relieve pain. This is clearly beneficial when we need relief from extreme pain that cannot be managed by natural endorphins alone.

Aside from pain relief; however, many opioid drugs also produce intense feelings of euphoria. When injected or smoked, heroin and fentanyl reach the brain very quickly. The drug molecules bind with opioid receptors in several brain regions, including the reward pathway. The result is large spikes in dopamine due to opioids inhibiting GABA, and thus increasing dopamine. However, tolerance quickly develops, requiring larger and larger doses to achieve the same effect. This ultimately leads to a vicious cycle of continuing drug use for many individuals.

Acute effects. In addition to elevated mood and euphoria, commonly used opioids also have several acute effects. Among the milder effects are flushing of the skin, dry mouth, nausea and vomiting, and drowsiness. However, what makes opioids especially dangerous is their ability to depress breathing. Breathing is regulated by structures located at the back of the brain. At high doses, opioids will bind to neurons in these areas and can dramatically slow breathing. In an overdose, breathing will cease and lead to hypoxia (lack of oxygen to the brain), which can cause death. If provided in time, the medications naloxone and naltrexone, which are opioid antagonists, can quickly reverse these effects.

Chronic effects. The health effects of chronic opioid use often depend on the route of administration used. Heroin often leads to constipation and sleep problems in most users. However, for those who smoke the drug, lung illness can also occur. For IV drug administration, damage to veins, blood vessels and organs can occur due to bacterial infections as well as contamination of the drug itself. Furthermore, the lifestyle of IV drug use is associated with poor physical and mental health. Sharing needles dramatically enhances the risk of acquiring bloodborne diseases (e.g., HIV). Lastly, opioid users often are more likely to suffer from mental health disorders, including depression and suicidal ideation.

Addiction potential. Along with cocaine, opioids like heroin and fentanyl are considered to have among the highest potential for addiction. Some people take opioids for medical reasons and can become dependent, especially after they develop tolerance to lower doses of the drug. This creates a dilemma between properly managing pain vs. avoiding longer-term use. Illicit use, such as with heroin or fentanyl, often results in addiction due to their potent effects on the reward system. Methadone is a synthetic opioid that is an effective substitute for heroin and fentanyl but without the same euphoric effects. It can be provided orally in a drink first thing in the morning and lasts a whole day. This allows the individual to manage withdrawal symptoms and to function in their everyday life. Lastly, treatment for opioid addiction normally involves detoxification, other opioid medications to help reduce craving, and cognitive-behavioral therapy.

That’s it for today; in tomorrow’s lesson, we are going to discuss hallucinogens. See you tomorrow!

 

Recommended book

Dreamland the True Tale of America’s Opiate Epidemic by Sam Quinones

 

Share with friends