Opioids (cancer treatment)
Opioids are controlled medications commonly prescribed for managing moderate to severe pain, particularly in cancer treatment. They comprise natural substances, such as morphine and codeine, as well as synthetic and semi-synthetic variations. The primary mechanism through which opioids alleviate pain involves binding to specific receptors in the central nervous system, effectively blocking pain signals and altering pain perception. While oral administration is the preferred route for its ease and cost-effectiveness, alternatives like transdermal patches and injections are available for patients unable to take oral medications.
Despite their effectiveness, opioids come with a range of potential side effects, including sedation, nausea, constipation, and risks of respiratory depression. There is also a significant concern regarding the potential for addiction, particularly given the historical context of opioid overprescription and its contribution to the opioid crisis in the early twenty-first century. Healthcare providers are tasked with carefully balancing pain management needs against these risks, especially as guidelines have shifted to promote more cautious prescribing practices. Despite recent trends indicating a reduction in opioid prescriptions, they remain vital for enhancing the quality of life in cancer patients, often used alongside non-pharmacologic therapies for comprehensive pain management.
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Opioids (cancer treatment)
ALSO KNOWN AS: Narcotics
DEFINITION: Opioids are controlled drugs prescribed for the management of moderate to severe pain. Opioids include natural alkaloids (opiates) such as morphine and codeine, which are extracted from the seedpod of the poppy plant, as well as semisynthetic derivatives and fully synthetic forms.
ATC CODE: N02A
Cancers treated: Various
Subclasses of this group: Phenanthrenes, phenylpiperidines, diphenylheptanes, benzomorphans
Delivery routes: Oral administration is preferred because it is the least invasive and least costly route. If a patient has difficulty swallowing or suffers from nausea or vomiting, other options may include rectal, transdermal, and transmucosal administration or injection under the skin or into the vein or spinal area. Patient-controlled access pumps that deliver opioids to these areas are also available. Opioids are produced in both long-acting and immediate-release forms, and they are often used with other pain medications for enhanced analgesia.
How these drugs work: Opioids mimic the body’s natural painkillers (for example, endorphins) by binding to receptors on the surfaces of cells in the central nervous system and gastrointestinal tract. Full agonists, the largest group of opioids, stimulate the receptors, blocking the release of neurotransmitters and interfering with the transmission of pain signals to the brain. They also alter the perception of pain. Partial agonists produce weaker effects and may also block the analgesic action of other opioids.
Opioids are often prescribed along with other medications or therapies to manage cancer pain. Non-pharmacologic therapies such as cognitive behavioral therapy, occupational therapy, physical therapy, and integrative therapies are often recommended to complement opioids.
Side effects: Adverse events are common across opioids and include sedation, nausea and vomiting, constipation, respiratory depression, dry mouth, itching, sexual dysfunction, and urinary retention. Because of the wealth of opioid receptor sites in the central nervous system, cognitive effects such as hallucinations, euphoria, and depression may also occur. Drug tolerance and physical dependence may develop. Doctors can often alter dosage to overcome tolerance and effectively manage pain; note that tolerance is not the same as addiction. However, opioids do bring a high risk of addiction, especially if abused.
The overprescription of opioids (and the understatement of their addictive potential) beginning in the 1990s is considered a key driver of the opioid abuse epidemic of the early twenty-first century, which resulted in drastic spikes in overdose death rates from both medical and illicit opioid drugs. This "opioid crisis" also created a stigma around the legitimate use of opioids for pain management and made it difficult for some patients to get access to needed medications. Amid efforts to reduce opioid prescriptions, the Centers for Disease Control and Prevention (CDC) issued guidelines on opioid use for chronic pain. However, it noted that cancer care presented a special exception. Healthcare providers increasingly work to ensure patients are prescribed the appropriate medications for their specific case and screen for risk factors associated with addiction.
Although in the mid-2020s, public health concerns have centered around reducing the number of opioids prescribed, they remain a critical part of cancer treatment and not just as palliative care. However, just as the general prescribing of opioids has trended downward, a 2021 study revealed that doctors were also prescribing fewer prescription opioids to cancer patients as well. Still, opioid pain medication remained an integral part of ensuring cancer patients maintained a quality of life throughout treatment, and medical professionals continued to find a way to balance pain management with concerns over opioid overuse.
Opioids can interact with other medications and substances, so patients should always consult their doctor carefully. Alcohol and tranquilizers can be especially dangerous when combined with opioids.
Bibliography
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"Cancer Pain: Relief Is Possible." Mayo Clinic, 12 Feb. 2021, www.mayoclinic.org/diseases-conditions/cancer/in-depth/cancer-pain/art-20045118. Accessed 14 June 2021.
“Opioids for Cancer Pain - Treatment and Side Effects.” American Cancer Society, 29 Mar. 2024, www.cancer.org/cancer/managing-cancer/side-effects/pain/cancer-pain/opioid-pain-medicines-for-cancer-pain.html. Accessed 28 June 2024.
Paice, Judith. "The Opioid Epidemic and Cancer Pain Management: A Conversation with Dr. Judith Paice." Interview. National Cancer Institute, US National Institutes of Health, 16 July 2018, www.cancer.gov/news-events/cancer-currents-blog/2018/opioid-crisis-cancer-pain-paice. Accessed 14 June 2021.
Piana, Ronald. “Studies Show That Laws to Limit Opioid Prescribing Have Hampered Pain Control for Patients With Cancer.” The ASCO Post, 25 Feb. 2022, ascopost.com/issues/february-25-2022/studies-show-that-laws-to-limit-opioid-prescribing-have-hampered-pain-control-for-patients-with-cancer. Accessed 28 June 2024.
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