What to know about these high-addictive substances, including possible side effects.

There's a lot of talk about the opioid epidemic and the challenges opioids can bring, but there's less discussion around the root question: What is an opioid drug?

Opioids are a class of drugs derived from the poppy plant. They are any "drug or medication that acts on the opioid receptors and systems in the brain," Michael Damioli, LCSW, the clinical director at Colorado Medication Assisted Recovery in Thornton, Colorado, tells Health.

The class includes prescription medications (designed for pain management), synthetic drugs (made in a lab), and illegal opioids (like heroin), says the National Institute on Drug Abuse (NIDA).

Illicit versions of opioids are believed to be the driver of a spike in opioid-related overdose deaths, which claimed the lives of more than 100,000 Americans in the 12-month period ended in April 2021, according to the Centers for Disease Control and Prevention (CDC).

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What are the most common prescription opioids?

Johns Hopkins Medicine lists many examples of opioid drugs. NIDA says the following five are commonly prescribed:

Oxycodone

This moderate-to-severe pain medication is taken every four to six hours as an extended-release capsule or every 12 hours as an extended-release tablet, says the US National Library of Medicine (NLM). Its brand names include OxyContin, Xtampza ER, Percocet, and Roxicodone. It is sometimes prescribed in combination with ibuprofen, aspirin, or acetaminophen. Potential side effects include dry mouth, drowsiness, headache, and mood changes. Severe side effects that require immediate attention include nausea, vomiting, irregular menstruation, hives, and difficulty breathing

Hydrocodone

This medication for severe pain can be taken every 12 hours as an extended-release capsule or once daily as an extended-release tablet, says the NLM. Its brand names include Vicodin, Norco, Lorcet, and Zamicet. It is sometimes prescribed in combination with ibuprofen or acetaminophen. Potential side effects include dry mouth, back pain, headache, difficulty sleeping, and ringing in the ears. Severe side effects that require immediate attention include nausea, vomiting, changes in heartbeat, irregular menstruation, hives, and difficulty breathing.

Morphine

Also for severe pain, morphine may be taken every four hours as an oral solution, every eight or 12 hours as an extended-release tablet, or every 12 or 24 hours as an extended-release capsule, says the NLM. Its brand names include MS Contin, Kadian, Morphabond, and Arymo ER. It is sometimes prescribed as Embeda, a combination drug including naltrexone. Potential side effects include drowsiness, mood changes, stomach cramps, headache, and nervousness. Severe side effects that require immediate attention include blue or purple skin tone, irregular menstruation, fainting, chest pain, hives, and fever.

Codeine

This opioid can be used for pain relief or prescribed to reduce coughing when combined with other medicines, says the NLM. Administered as a tablet, capsule, or liquid, codeine may be taken even four to six hours as needed. Doctors may prescribe this opioid under the brand name Tuzistra XR. There are also dozens of other combination products containing codeine, such as Robitussin. Side effects include headache, stomach pain, and difficulty urinating. A review published by the NLM also cites constipation as one of the most common adverse effects. It can also cause nausea or vomiting.

Fentanyl

This synthetic opioid is prescribed to help with severe post-surgery pain or when someone with recurring pain builds up a tolerance to other opioids, reports NIDA. Potential side effects of fentanyl, per NLM, include depression, weight loss, unusual dreams, dry mouth, and chest pain. Severe side effects that require immediate attention include hallucinations, hives, shallow breathing, and fainting.

Fentanyl works the same way as other opioids but is much more addictive. "Fentanyl can be up to 50 times more potent than heroin and up to 100 times more potent than morphine," Ashley McGee, RN, the vice president of nursing at Mountainside treatment center based in Connecticut, tells Health.

Which opioid drugs are illegal?

Some types of opioids are purchased on the street and used to get high, says NIDA.

Heroin

Made using morphine, heroin comes either as a white or brown powder or as a black sticky tar, says NIDA. Similar to other opioids, this drug creates a euphoric feeling that can remove pain. Potential side effects of heroin include dry mouth, heaviness of the arms and legs, nausea, vomiting, and brain fog. Long-term exposure to heroin can cause insomnia, collapsed veins, stomach cramping, constipation, liver or kidney disease, and more.

People take heroin by snorting, injecting, sniffing, or smoking it. These methods help heroin reach the brain very quickly, causing its fast-acting and addictive nature, reports the NLM.

Illicitly manufactured fentanyl

Versions of fentanyl made and used illegally may come in different forms, including liquid and powder, says the CDC. In September 2021, the US Drug Enforcement Administration (DEA) warned of an "alarming increase" in counterfeit prescription pills laced with fentanyl.

According to the DEA, some street drugs, such as counterfeit OxyContin or Xanax, often contain an unknown amount of fentanyl—potentially enough to be fatal with one hit (as the US Food and Drug Administration warns).

Damioli advises that anyone who takes drugs recreationally consider acquiring a fentanyl test kit online or from a local harm reduction center to test drugs before use. (The use of fentanyl test strips is considered a safe and simple strategy for reducing overdose deaths, researchers point out in a June 2021 Health Affairs blog.)

Do opioids interact with other drugs?

Due to their addictive nature, it's best to avoid opioid drugs when possible. However, some people have a greater incentive to steer clear of them. Opioid interactions with other drugs can be risky. McGee cautions that people who "drink or use benzodiazepines such as Xanax should not use opioids, as each of these substances suppresses breathing, increasing a person's risk of overdose."

McGee adds that people who have chronic pain or a family history of substance use disorders may also want to avoid opioids. In the case of chronic pain, people tend to build a tolerance to opioids, making the same dose less effective over time and requiring more drugs if taken long-term. NIDA reports that between 8% and 12% of people taking opioids for chronic pain go on to develop opioid use disorder.

As for genetics, people with family members who have a history of addiction to opioids or other substances appear to be at a greater risk of addiction, reports the NLM.

"A person's genetic makeup and psychological predisposition have a huge influence on whether or not someone becomes addicted," adds Damioli. He cautions against using opioids and advises sharing any concerns with your doctor to see if you can instead use another, less addictive medication. If a medical professional deems opioids as necessary, ask about the shortest and smallest course you can take—and don't be afraid to get a second opinion about other options.

Damioli also recommends having a trusted loved one hold you accountable by hanging on to your medication and only giving prescribed doses to you. Of course, avoid choosing someone who may be inclined to misuse opioids themselves.

What are the signs of opioid dependence?

Whether by prescription or illegal means, it's easy to become dependent on opioids. Between 21% and 29% of people misuse opioids prescribed for chronic pain, says the NIDA. As for heroin, 80% of people who try the drug first misused opioids, it says.

"Stronger opioids whose effects wear off quicker, such as heroin or fentanyl, are more likely to create dependency than are weaker and longer-acting opioids," says Damioli. "Any and all opioids can become addictive depending on how much and for how long the user consumes the drug."

According to McGee, signs of opioid drugs dependence include:

  • Using opioids differently than initially prescribed, such as taking larger or more frequent doses than recommended by a doctor
  • Having an increased tolerance for opioids
  • Experiencing withdrawal symptoms when stopping opioid use, such as muscle aches, chills, nausea, cramps, and strong opioid cravings

In the case of an opioid drug overdose, individuals can take naloxone, commonly known by the brand name Narcan. According to NIDA, it is an opioid antagonist, meaning it reverses or even stops the effect of opioids. A person overdosing can receive naloxone through an injection or nasal spray—the latter is more common for untrained individuals to provide. The effects of naloxone only work for about 30 to 90 minutes, so medical attention should be immediately sought regardless of if a person receives the medication or not.

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