Side Effects Of Opioids: Short-Term And Long-Term Effects

Opioid misuse remains one of the most pressing public health crises in the United States, affecting millions of people across every demographic and region of the country. While recent data shows encouraging signs of progress, including a decline in overdose deaths in 2024, the crisis is far from over, and opioid drugs continue to be among the most commonly misused and most deadly substances in circulation.

The most frequently misused opioids include prescription drugs like oxycodone, hydrocodone, morphine, codeine, and fentanyl, as well as illicit drugs like heroin and illicitly manufactured fentanyl.  All of these substances work by depressing the central nervous system to relieve pain and produce euphoria, and all carry a high potential for dependence, addiction, and fatal overdose when misused.

How Do Opioids Affect The Brain?

Although opioids vary in potency, they all work to slow down the central nervous system (CNS) that regulates vital functions.

When the CNS slows down, it impacts:

• blood pressure
• respiration
• heart rate

Opioids also impact the parts of the brain that control:

• mood
• impulse control
• coordination
• ability to sleep
• desire for food

Opioids and opiates bind to mu-opioid receptors that facilitate the release of dopamine, which gives people a sense of well-being and euphoria. When a person abuses opioids, it can prevent the body from releasing some natural chemicals, which can lead to drug dependence and addiction.

How Do Opioids Affect The Body?

A person that smokes, snorts or injects an opioid will feel its effects within a few seconds. People that take pills orally, like oxycodone or hydrocodone, will feel effects within a few minutes.

The immediate impact on the body leads to generally slowed responses and reduced pain. A high-potency opioid like fentanyl, or a large dose of heroin, can produce rapid physical effects that may cause life-threatening conditions.

General opioid effects on the body result in:

• extreme relaxation/drowsiness
• nausea
• vomiting
• itchy, flushed skin
• dry mouth
• constricted pupils (“heroin eyes”)
• slowed, labored breathing
• “nodding” in and out of consciousness (known as the heroin nod)

Short-Term Effects Of Opioid Misuse

The short-term effects of opioid abuse include increased risk of overdose along with damage to a person’s ability to think and function normally.

Immediately after taking an opioid, a person may experience:

• memory problems
• extreme sedation
• dulled senses

Upon taking an opioid, the lingering effects on the body and brain can last upwards of several hours.

Increased Overdose Risk

A person may experience an overdose when they take too much of an opioid drug, use opioids with other CNS depressants such as benzodiazepines or alcohol, or accidentally ingest opioids laced with stronger opioids like fentanyl.

Some symptoms of an opioid overdose include:

• unconsciousness
• vomiting
• shallow, labored breathing
• choking or gurgling
• pale/clammy/cold skin
• unresponsiveness
• coma
• tremors/seizure

Long-Term Effects Of Opioid Addiction

People that abuse opioids may suffer from a wide range of effects to their direct mental and physical health, and with their ability to function normally. Psychological addiction and physical dependence can result from prolonged opioid use.

Major long-term effects include an increased risk of death stemming from prolonged damage to the heart and major organs.

Death may occur from chronic opioid use due to:

• HIV/AIDS (sharing needles)
• hepatitis C
• stroke
• heart attack
• endocarditis (heart infection)
• kidney damage

Persistent opioid use can result in chronic conditions that impact daily function that include:

• mood swings
• drug cravings
• constipation
• insomnia
• skin infections (injecting drugs)
• nasal infections (snorting drugs)
• lung infections (smoking and snorting drugs)
• addiction
• dependence
• drug tolerance
• cravings

Opioid Addiction And Dependence

People that use opioid drugs can become psychologically dependent and physically dependent on the drugs to function normally. The absence of opioid drugs can cause a range of negative withdrawal symptoms that result from a person’s dependence.

Opioid Withdrawal Symptoms

Opioid withdrawals can begin to occur within hours of a person’s high tapering off. Withdrawals increase in intensity when a person begins detoxification, which can last upward of a week, depending on the substance they use.

Some symptoms that many people experience when going through withdrawals can include:

• extreme drug cravings
• depression
• anxiety
• restlessness/irritability
• nausea
• vomiting
• body aches
• cold flashes
• general dissatisfaction (dysphoria)
• insomnia

In general, opioid withdrawal symptoms can be managed in an inpatient setting with the use of therapeutic drugs like naltrexone, methadone, and buprenorphine. Some rehab facilities may use benzodiazepines or anti-anxiety medication to help ward off extreme anxiety or restlessness.

Treatment For Opioid Addiction

Recovery from dependence and addiction to opioids can include a range of treatment options. In general, a combination of individual behavioral therapy, detoxification, and medications like buprenorphine or methadone can be effective.

Browse our directory or reach out to the Substance Abuse and Mental Health Services Administration (SAMHSA) for more helpful information about treatment options and recovery.