Introduction

Since 1999, over one million people in the United States have perished from drug overdoses. In 2021, over 75% of these deaths were the result of an opioid. From 1999 to 2021, the number of opioid-related deaths increased ten times, taking the lives of over 80,000 people in 2021 alone (1). The trend has continued on an upward track with record-level deaths in 2023, with over 111,000 individuals dying because of this drug epidemic (2).

It is apparent that opioid use is a severe problem in the United States. Opioid drugs include prescription pain medication and illegal drugs and are highly addictive. Addiction to opioid drugs is called Opioid Use Disorder (OUD) (3). Opioid use disorder has a significant impact on the quality of life for those experiencing it, causing impairment, despair, distress, and possible loss of life.

Definition 

While opioid is common terminology, opioid drugs are also referred to as opiates, narcotics, or painkillers. They are a class of drugs that originate from or imitate the natural substances found in the opium poppy plant (3). 

The Difference between Opiates and Opioids

The main difference between opiates and opioids is in how they are made. The chemical compounds in opiates originate from natural plant matter from the poppy plant, while opioids are fully or partially manufactured in labs or synthesized.

Both opiates and opioids are used medically, and many use the terms interchangeably. The term opioid is most frequently used for both. While both are used medically, both are also used illicitly. Both are controlled substances in the United States, and both have a high potential for misuse and risk of dependence (4).

Some examples of each are (5):

Opioid Use Disorder

Opioid use disorder is considered a mental health condition characterized by a pattern of opioid misuse that results in distress and disruption of life. OUD occurs on a spectrum and can be mild, moderate, or severe. OUD is a chronic disorder and can result in disability, relapses, overdoses, and death (7).

Opioid use disorder and opioid addiction are at epidemic levels in the United States and worldwide. In the United States, approximately three million people are suffering from OUD, with over 500,000 addicted to heroin (6). Opioid use, addiction, and overdose have become so prevalent that it is now considered to be a crisis. Contributing to this crisis is the number of overdose deaths related to opioids.

The CDC identified three waves of overdose deaths related to opioids (16).

First Wave- Prescription Medications- The first wave occurred in the 1990s and is related to the increase in providers prescribing opioids. The rate of death related to prescription opioids began to rise.

Second Wave-Heroin – The second wave started in 2010 and was related to the availability of heroin. This increased from overdose deaths linked to heroin.  

Third Wave- Synthetic opioids – The third wave began in 2013 and involves synthetic opioids. The overdose deaths related to this type of opioid rose rapidly, and most of these deaths were a result of fentanyl. Fentanyl was readily available and was also found in other drugs.

Recognizing these waves, it’s essential to ask what contributes to this epidemic of opioid use and opioid-related deaths, and are there specific factors for individuals putting them at a higher risk than others for OUD? Evidence has revealed that overprescribing opiates and opioids, lack of education, and being unmarried or divorced are definite contributing factors (17).

Anyone taking opioids can be at risk for OUD, but it is not possible to determine who will become dependent, misuse, or become addicted. However, opioids are more addictive when taken in a way other than for which they were prescribed (18). In addition, how long opioids have been prescribed is a strong indicator of misuse.

Environmental, genetic, and psychological factors all have a role in the possibility of opioid misuse, resulting in the following risk factors (18):

• Age: younger people in their teens and early 20s
• Having a personal or family history of substance abuse
• Heavy tobacco use
• Having a criminal history or legal issues
• History of DUIs
• High levels of stress
• Unemployment
• Difficulty in school
• Difficulty at work
• Relationship problems
• Depression, anxiety, or post-traumatic stress disorder
• History of physical or sexual abuse
• Risky behaviour or thrill-seeking

Opioids are highly addictive, mainly because of their ability to trigger powerful reward centers in the brain (18). OUD has been described as a condition that starts as pleasurable but then turns into something the individual cannot live without. It is an out-of-control feeling and desire to use the drug even though it causes distress and harm repeatedly (18).

Pharmacokinetics

Definition

Opioids are a class of drugs that work in the brain. While they have various effects, the most common is for pain relief. However, many people use opioids for the feelings of euphoria they generate. This euphoria or high can lead to addiction or OUD (3).

Drug Class

Opioids are a class of drugs specifically used to reduce pain. This includes prescription pain relievers and illegal substances, such as heroin.

Uses

Physicians prescribe prescription opioids for the treatment of moderate to severe pain. They may also be used to treat cough and diarrhea. They are powerful pain-reducing medications and are also referred to as narcotics.

Some conditions they are indicated for include (8):

• Chronic pain
• Acute pain
• Vascular pain
• Chronic headaches
• Chronic backaches
• Recovering from surgery
• Pain associated with cancer.
• Injuries
• Diarrhea
• Irritable bowel syndrome
• Cough suppressants

Chronic pain is defined as pain that lasts over three months. It is estimated that approximately 51.6 million people in the United States are impacted by chronic pain, and 17.1 million experience high-impact chronic pain (10). Opioids given orally result in immediate and effective relief of severe and acute pain.

While opioids can be an essential tool in pain management, there is insufficient evidence supporting the long-term benefits of prescription opioid treatment for chronic pain (11). Long-term prescription use of opioids has also been linked to increased risk of overdose and opioid misuse (11).

The United States Food and Drug Administration (FDA) approves the opioid Loperamide (Imodium) as an anti-diarrheal medication. It is used for diarrhea and irritable bowel syndrome and works by decreasing intestinal motility and increasing absorption time (9).

The opioids codeine and dextromethorphan are commonly used as cough suppressants. Codeine is effective as a cough suppressant as it also acts as an analgesia and sedative (9).

Mechanism of Action

Opioids affect the brain. They work by attaching to and activating opioid receptors in the brain, spinal cord, and other areas of the body (12). Opioids have a significant impact on pain as they block pain signals between the brain and the body (12).

There are three types of opioid receptors. Opioid receptors are located throughout the central and peripheral nervous systems and the gastrointestinal tract. Receptors exist on the surface of cells and receive messages that tell them what to do (12, 14). They regulate many body functions, such as pain, mood, stress, reward, gastrointestinal functions, and respiration (23).

The three receptors are included in the group of proteins called the G-protein-coupled receptors and are (12):

• Mu receptors
• Delta receptors
• Kappa receptors

When opioids are ingested, the effects are immediate, and changes occur in the brain and the central nervous system.

Areas impacted are (12):

• The Limbic System
  • Opioids impact the limbic system, which affects the emotions of happiness and relaxation.
• The Brainstem
  • Opioids impact the brainstem, which controls the automatic body functions such as breathing and metabolism. This explains why toxic levels of opioids can stop breathing.
• The Spinal Cord
  • Opioids impact the spinal cord, which is important in pain relief.

Our bodies produce endogenous opioids naturally. These are also called endorphins and are produced during certain activities that stimulate feelings of happiness and relaxation (12). Opioids work similarly by activating the reward circuitry in the brain and releasing dopamine. Dopamine is also known as the feel-good neurotransmitter (12).

Physiological Effects

Central Nervous System (CNS)

Opioids affect the CNS, and common signs include (19):

• Euphoria
• Mood changes
• Mental clouding
• Drowsiness
• Pain reduction
• Pupillary constriction: In response to the stimulation of the oculomotor nerve
• Respiratory depression: Related to depression of the respiratory centers within the medulla.
• Nausea and Vomiting: Related to the stimulation of the centers of the medulla.

Gastrointestinal Effects

Opioids have a significant effect on the gastrointestinal tract.

The effects include (19):

• Stomach and intestinal tone increase, resulting in diminished peristaltic activity.
• A decrease in the movement of food through the gastrointestinal tract.
• Constipation
• Fecal impaction

Cardiovascular Effects

Opioids can be very effective in treating pulmonary edema and myocardial infarction pain if given in therapeutic doses. However, if misused and given at higher doses, it can be very harmful, resulting in the following (19):

• Hypotension
• Cardiac dysrhythmias

Sexual Function

Opioid use can result in decreased sexual function, including (19):

• Diminished libido
• Erectile dysfunction
• Delayed ejaculation
• Impotence
• Orgasm failure

Side Effects and Risks

There are significant side effects and risks when taking opioids that include (15):

• Drowsiness
• Mental fog
• Constipation
• Nausea
• Slowed breathing – The side effect of slowed breathing is significant, as this could indicate an overdose.

Additional signs of overdose include (15):

• Loss of consciousness
• Choking, gurgling sounds
• Vomiting
• Pinpoint pupils
• Limp body
• Pale or blue skin
• Purple fingernails
• Cold skin
• Faint heartbeat

Drug Tolerance

Taking opioids for an extended period can result in drug tolerance. This occurs when more of a drug is needed to achieve the same effects as before (13). This results from a change in the receptors and reward pathways, which causes a diminished response to the drug. Therefore, more of the drug will be needed to achieve the desired response, whether pain relief (pain pathway) or euphoria (reward pathway). This is frequently called “chasing a high” (13).

Drug Dependence

As more opioids are taken, the neurons of the brain do not function normally. The neurons have adapted to repeated exposure to the drugs and cannot function normally without the drug. Drug dependence can happen to anyone who uses opioids repeatedly (13). Dependence occurs because of repeated exposure to opioids and results in withdrawal symptoms if the drug is no longer present (15).

Drug Withdrawal

Drug withdrawal can occur if opioids are discontinued in someone who is drug dependent. The brain has become accustomed to having opioids.

Drug Addiction

OUD, or addiction, can be defined as an uncontrollable need to use substances regardless of the harmful effects on the body or consequences to daily life (15). Addiction happens when opioids activate the reward pathway, resulting in a strong desire to continue using. Addiction develops when a compulsion to use more opioids to activate the reward pathway of the brain takes over (13).

Nursing Considerations

The opioid epidemic is considered a public health crisis in the United States, causing harm, distress, and death. The use of opioids increases the risk of injury and accidental death. If the drug is injected, there is a risk of infectious diseases, including HIV, hepatitis B, hepatitis C, and bacterial endocarditis (20).

Nurses are key in dealing with this epidemic. It is essential that nurses know about opioid addiction and the consequences related to it. Along with the risks mentioned previously, it is important that nurses recognize and respond to the serious conditions of opioid intoxication and opioid withdrawal.

Opioid Intoxication

Opioid intoxication occurs when the individual not only experiences euphoria but also develops body-wide symptoms resulting in impairment and illness (21).

The symptoms include.

• Altered mental status, confusion, delirium, decreased awareness or responsiveness.
• Difficulty breathing
• Sleepiness
• Loss of alertness
• Nausea and vomiting
• Pinpoint pupils

Nurses must recognize these key signs and respond with the appropriate treatment.

Treatment for opioid intoxication includes the narcotic antagonist of Naloxone (Narcan) or Naltrexone (Vivitrol) to prevent relapse (20).

• Naloxone (Narcan) – This is an FDA-approved medication that rapidly reverses an opioid overdose. It is an opioid antagonist that binds to the opioid receptors and can reverse and block the effects of opioids (25)
• Naltrexone – This is an FDA-approved medication that treats alcohol use disorder and opioid use disorder. It blocks the euphoric and sedative effects of opioids by binding and blocking opioid receptors. It reduces and suppresses opioid cravings. (27).

Opioid Withdrawal

The body becomes desensitized to the effects of opioids after prolonged use. As a result, more of the drug is needed to achieve the desired effect. If the opioid is stopped, it may result in physical illness. Everyone experiences opioid withdrawal differently, and it depends on the level of withdrawal experienced.

The symptoms of opioid withdrawal include (22):

• Muscle aches
• Runny nose
• Frequent yawning
• Restlessness
• Lacrimation
• Diaphoresis
• Insomnia
• Diarrhea
• Goosebumps on the skin
• Nausea and vomiting
• Blurry vision
• Dilated pupils
• Rapid heart rate

Opioid withdrawal is uncomfortable, with unpleasant symptoms. Treatment provided in a controlled environment results in a higher success rate and includes (22):

• Adequate fluids
• Adequate rest
• Mild withdrawal can be treated with Tylenol or NSAIDs
• Nutritional support
• More intense withdrawal may be treated with Clonidine, Methadone, or Buprenorphine (19).

Clonidine (Catapres) 

This medication is commonly prescribed for the management of blood pressure. Still, it is also used off-label to decrease opioid withdrawal symptoms and helps to maintain more extended periods of abstinence from opioids. It is an alpha-2-adrenergic agonist and inhibits the release of norepinephrine.

It can assist in decreasing the following withdrawal symptoms of (26):

• Agitation
• Sweating
• Muscle aches
• Elevated heart rate
• Elevated blood pressure

Methadone

This is an FDA-approved medication used to treat opioid use disorder. It is a long-acting full opioid agonist. It is also a Schedule II-controlled medication. Methadone is also used for pain management. This medication reduces opioid cravings and withdrawals and blocks the effects of opioids (29).

Buprenorphine

This is an FDA-approved medication used to treat opioid use disorder. This is an opioid partial agonist. It produces the effects of euphoria at low to moderate doses.

This medication assists in (28):

• Decreasing the effects of physical dependency, withdrawal symptoms, and cravings.
• Lowers the potential of misuse.
• Increases safety in cases of overdoses.

New Research

Opioids are commonly used in the treatment of moderate to severe pain, including chronic pain. Over 50 million Americans suffer from chronic pain, the majority of these being over 65 years of age. Many individuals in this age group are already at risk for cardiovascular disease. A recent study has found that those in this age group who had received prescribed opioids were significantly at risk of developing cardiovascular disease (24).

With the increase in opioid use and OUD, the negative effects of opioid addiction and opioid overdoses may just be starting.

Conclusion

The statistics related to opioid use and opioid use disorders are overwhelming. Opioid use disorder and addiction remain at epidemic levels. This condition can affect individuals from all socioeconomic and educational backgrounds. Therefore, nurses need to understand and be knowledgeable about opioids and opioid use disorder. Awareness of medical and illicit use of opioids is necessary to understand this growing public health concern.