Opioid Drug Class: What Drugs Are Classified As Opioids?

Last Updated: June 3, 2020

Reviewed by Michael Espelin APRN

Depressants, stimulants, benzodiazepines, and barbiturates are often mistaken as classes of opioids. These drugs are available by prescription because they are highly addictive, and there are no OTC opioids. If they are highly addictive, why are opioids prescribed?

The Centers for Disease Prevention and Control have set up guidelines as part of opioid crisis solutions that aim to restrict access to these painkillers. A study by Argoff and Silvershein recommend that physicians must carefully consider the nature of pain, therapeutic goals, and evidence of the efficacy of short-acting and long-acting opioids for the management of CNCP. The same considerations should remain valid when weighing the risks and benefits of prescribing extended-release opioids.
What makes them different from other drug classes? What medications are considered opioids?

Are Opioids Depressants?

A common question many people ask is: are opioids CNS depressants? Many people think that muscle relaxants, pain relievers, and opioids are depressants. Although all three slow down the body, hence often tagged as “downers,” each one belongs to a different drug class and do not, technically, fall under “depressants”.
Opioids come from a class of drugs called opium-related painkillers which act on nerves in the brain and spine which mislead many people to thinking that opioids are CNS depressants.

Are Opioids Stimulants?

Stimulants, also known as “uppers,” like Adderall and Ritalin improve alertness, memory and cognitive performance. While natural or synthetic, legal or illegal, they cause heartbeat and the respiratory activity to slow down, stimulants have the opposite effect. Stimulants increase blood pressure and open up air passages. Stimulants can mimic the euphoric effect of another drug class, however.

Are Antidepressants Opioids?

These two are different classes of prescription drugs that should not be confused with each other. Even though some practitioners had routinely prescribed these painkillers to counter depressive symptoms in the same way that antidepressant can elevate mood.
Whereas painkillers from this drug class are prescribed only for severe levels of pain, antidepressants are routinely prescribed for treating sleep disorders, restlessness, sexual problems, and headache.

woman asking for advice

Are Benzos Opioids?

Drugs from benzodiazepines drug class  have an immediate, hypnotic effect. These are intended to sedate a person to ease anxiety, seizures, and panic disorders. Although benzos affect brain signalling, they specifically interact with the neurotransmitter, gamma-aminobutyric acid-A (GABA-A) only. The new CDC Guidelines stresses that painkillers from this drug class and benzos must not be combined. That’s because they have a sedating effect on the body, and both cause the respiratory activity to slow down.

Are Barbiturates Opioids?

Barbiturates are broadly classified by NIDA as CNS depressants which inhibit brain activity. They also slows down heartbeat, lowers blood pressure, and slows down breathing.
These two, however, belong to different drug classes. Barbiturates affect the CNS, whereas others affect the transmission of signals to the brain, which makes these effective painkillers.

What Medications Are Considered Opioids?

They relieve pain by binding with receptors in the brain, spine, gastrointestinal tract, and other areas of the body. Based on the current recommended practice, they must only be used to relieve moderate to severe pain that does not respond to other non-opioid pain medicines.
Their use carries risks for developing tolerance, however. These painkillers also activate reward regions in the brain which further increases the risk for misuse and dependence. Other side effects include memory loss, difficulty sleeping, and loss of appetite. Although a person’s tolerance to some side effects can be expected to develop over time, adverse affects like constipation will require opioid constipation treatment.

Long vs. Short-Acting

These meds are described to be long-acting or short-acting depending on the duration of action. Long-acting opioids are designed as extended-release medication and may last between 8 to 72 hours. This makes extended-release opioids for chronic pain more effectively. Essentially, long-acting opioids list include all medications, except that these are designed in preparations enabling slow or controlled release.
On the other hand, short-acting ones are designed as immediate-release opioids. The dosage per day is limited. These are typically prescribed for pain characterized as acute, chronic, but intermittent or breakthrough. Short-acting opioids list includes all the manes, except for very few like methadone which is inherently long-acting.
If a patient cannot tolerate the side effects of a prescribed medicine, physicians may recommend switching the patient to another one. To ensure patient safety, physicians use the opioid conversion guidelines to compute for the calculated dose-equivalent of the replacement medication.

What Schedule Are Opioids?

The U.S. Drug Abuse Prevention and Control Act prompted the classification of opioids, including the categorization of controlled substances. Opioids schedules cut across all five categories of the schedule for controlled substances, usually determined using the level of codeine.
Opioids that are categorized under Schedule II and Schedule III. More detailed information is summarized in the table below.

Schedule II Schedule III
Hydrocodone/Codeine Content Contain between 9 to 15 mg of hydrocodone per dosage unit Contain less than 90 mg of codeine per dosage unit
  • Percocet (oxycodone) Vicodin
  • OxyContin
  • Dilaudid (hydromorphone)
  • Demerol (meperidine)
  • Dolophine (methadone), Duragesic or Sublimaze (fentanyl)
  • Morphine
  • Opium
  • Buprenex
  • Suboxone
  • Subutex
  • Temgesic

*All are classified as buprenorphine

The US Drug Enforcement Administration uses the following definitions and categories of Drug Scheduling:

  • Schedule II: Drugs have a high likelihood of being abused and becoming addictive.
  • Schedule III: Drugs have a low to moderate potential to lead to addiction and dependence.

Despite the highly addictive nature of these medications, manufacturers and distributors vouched for the safety of use of these drugs which have led physicians and the public to use this drug class even for mild or moderate types of pain. The high rates of prescription in the past decades has fuelled today’s crisis. People have filed an opioid class-action lawsuit seeking to make several pharmaceutical companies accountable for the crisis.

 man asking the doctor about opioids

Use Them Only As Prescribed

They can be helpful in managing pain if used correctly and only with a prescription. In case of any addiction signs noted, seek addiction treatment immediately.
Detox step is generally recommended to overcome dependence to this medication. Opioid withdrawal medication may be necessary to manage withdrawal symptoms and encourage treatment continuation.
When a person took these painkillers intravenously, opioid substitution therapy must be considered to introduce options that lessen a person’s risk for co-morbidities associated with drug use, including HIV. Qualified specialists in drug rehabs will help to find the best treatment approach for each case.

Page Sources

  1. Centers for Disease Control and Prevention, 2018 Annual Surveillance Report of Drug-Related Risks and Outcomes — United States. Surveillance Special Report 2, https://www.cdc.gov/drugoverdose/pdf/pubs/2018-cdc-drug-surveillance-report.pdf
  2. Charles E. Argoff, Daniel I. Silvershein, A Comparison of Long- and Short-Acting Opioids for the Treatment of Chronic Noncancer Pain: Tailoring Therapy to Meet Patient Needs, https://www.mayoclinicproceedings.org/article/S0025-6196(11)60749-0/fulltext

Published on: September 17th, 2019

Updated on: June 3rd, 2020

About Author

Peter J. Grinspoon, MD

Dr. Peter Grinspoon is an experienced physician with long-term clinical practice experience. As a former analgesic addict, Dr. Grinspoon knows precisely how important it is to provide patients with effective treatment and support. Medical writing for him is the way to communicate with people and inform them about their health.

Medically Reviewed by

Michael Espelin APRN

8 years of nursing experience in wide variety of behavioral and addition settings that include adult inpatient and outpatient mental health services with substance use disorders, and geriatric long-term care and hospice care.  He has a particular interest in psychopharmacology, nutritional psychiatry, and alternative treatment options involving particular vitamins, dietary supplements, and administering auricular acupuncture.


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