Opioid mechanisms and opioid drugs

Opioids and the Kidney: A Compendium

Opioids are a class of medications used in pain management. Unfortunately, long-term use, overprescription, and illicit opioid use have led to one of the greatest threats to mankind: the opioid crisis. Accompanying the classical analgesic properties of opioids, opioids produce a myriad of effects including euphoria, immunosuppression, respiratory depression, and organ damage. It is essential to ascertain the physiological role of the opioid/opioid receptor axis to gain an in-depth understanding of the effects of opioid use. This knowledge will aid in the development of novel therapeutic interventions to combat the increasing mortality rate because of opioid misuse. This review describes the current knowledge of opioids, including the opioid epidemic and opioid/opioid receptor physiology. Furthermore, this review intricately relates opioid use to kidney damage, navigates kidney structure and physiology, and proposes potential ways to prevent opioid-induced kidney damage.

Remote local photoactivation of morphine produces analgesia without opioid-related adverse effects

BACKGROUND AND PURPOSE

Opioid-based drugs are the gold standard medicines for pain relief. However, tolerance and several side effects (i.e. constipation and dependence) may occur upon chronic opioid administration. Photopharmacology is a promising approach to improve the benefit/risk profiles of these drugs. Thus, opioids can be locally activated with high spatiotemporal resolution, potentially minimizing systemic-mediated adverse effects. Here, we aimed at developing a morphine photo-derivative (photocaged morphine), which can be activated upon light irradiation both in vitro and in vivo.

EXPERIMENTAL APPROACH

Light-dependent activity of pc-morphine was assessed in cell-based assays (intracellular calcium accumulation and electrophysiology) and in mice (formalin animal model of pain). In addition, tolerance, constipation and dependence were investigated in vivo using experimental paradigms.

KEY RESULTS

In mice, pc-morphine was able to elicit antinociceptive effects, both using external light-irradiation (hind paw) and spinal cord implanted fibre-optics. In addition, remote morphine photoactivation was devoid of common systemic opioid-related undesired effects, namely, constipation, tolerance to the analgesic effects, rewarding effects and naloxone-induced withdrawal.

CONCLUSION AND IMPLICATIONS

Light-dependent opioid-based drugs may allow effective analgesia without the occurrence of tolerance or the associated and severe opioid-related undesired effects.

LINKED ARTICLES

This article is part of a themed issue on Advances in Opioid Pharmacology at the Time of the Opioid Epidemic. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v180.7/issuetoc.

Does the Addition of Naloxone in Buprenorphine/Naloxone Affect Retention in Treatment in Opioid Replacement Therapy?: A Systematic Review and Meta-Analysis

BACKGROUND

Opioid maintenance therapy is an evidence-based first-line treatment approach to reduce the problems associated with opioid use disorders. Buprenorphine and methadone are the two most commonly recommended pharmacotherapies. Individuals who remain in treatment longer tend to have a reduced drug use, a higher social functioning, and a higher quality of life. The addition of naloxone to buprenorphine (bup/nx) was developed, in part, to help increase retention in treatment. However, this has not been shown in research. The objective of this review was to examine whether bup/nx is more effective than buprenorphine and methadone, to ultimately determine whether the addition of naloxone shows a clinical difference.

METHODS

The literature search was conducted using the electronic databases PubMed, Embase, and Cochrane. Search strategies were thoroughly developed and modified for each database by combining relevant MeSH and Emtree terms as well as keywords such as "bup/nx," "buprenorphine," and "naloxone." The outcome measure was treatment retention, as determined by the number of days a participant remains in a treatment program.

RESULTS

There were four studies included in the review. The data were analyzed with Review Manager software. There was no statistically significant result for bup/nx compared with methadone or buprenorphine.

CONCLUSION

Bup/nx may be an alternative to standard treatments such as buprenorphine and methadone as the addition of naloxone does not affect retention in treatment.

Morpheus and the Underworld-Interventions to Reduce the Risks of Opioid Use After Surgery: ORADEs, Dependence, Cancer Progression, and Anastomotic Leakage

BACKGROUND

Perioperative pain management is a key element of enhanced recovery after surgery (ERAS) programs. A multimodal approach to analgesia as part of a coordinated ERAS includes the reduction of opioid use. This review aims to discuss opioid-related adverse events, strategies to reduce opioid use after surgery, and the relevance to the present "opioid crisis" in North America.

METHODS

A literature review of the pharmacology of opioid drugs, perioperative opioid reduction strategies, and the potential public health benefit was performed. This included current ERAS guidelines on multimodal analgesia, randomized controlled trials on perioperative analgesia, and intervention studies to decrease opioid use, misuse, and diversion in North America.

RESULTS

Reduction of perioperative opioid usage has been endorsed by joint clinical practice guidelines on the management of postoperative pain from the American Pain Society, the American Society of Regional Anesthesia and Pain Medicine, and the American Society of Anesthesiologists. Interventions as part of an "opioid bundle" that can be incorporated into ERAS protocols include multimodal analgesia, regional anesthesia, opioid sparing drugs, carbon dioxide humidification during laparoscopy, changing opioid prescription practices, patient and physician education, and proper disposal of unused opioid medications.

CONCLUSION

There are substantial benefits in incorporating opioid reduction strategies into ERAS and clinical practice guidelines. These include faster return of function and mobility, and decreased opioid-related adverse drug events (ORADEs), postoperative morbidity and mortality, and length of hospital stay. Improved oncological outcomes after cancer surgery may be an additional benefit. Evidence-based interventions can also reduce opioid abuse and diversion in the community.

Management of Opioid Use Disorder Treatment: An Overview

It is important for nurses not working in the area of addictions to be informed of the diagnosis and treatment of opioid use disorder so that they may serve as a resource, educate others, and influence and refer individuals to seek treatment on the basis of best evidence. In this article, we provide an overview of the postscreening diagnosis and treatment of opioid use disorders with an emphasis on medication-assisted treatment, starting with the definition of substance use disorder, tolerance, dependence, and addiction.