Fentanyl and Propofol Exposure in the Operating Room: Sensitization Hypotheses and Further Data

A comprehensive analysis of propofol abuse, addiction and neuropharmacological aspects: an updated review

This review aims to assess the existing studies on propofol, a relatively new intravenous anesthetic, related to its abuse and addictive potential and to explain the neurobiological and neuropharmacological aspects of propofol addiction. Several neurobiological factors related to complex processes in the brain influence propofol abuse and addiction. In this review, we assessed the literature regarding propofol abuse and addiction, including both experimental and clinical studies. We selected articles from animal studies, case reports, clinical trials, meta-analyses, narrative reviews, and systematic reviews to extract all relevant crucial quantitative data with a measure of neurobiological and neuropharmacological aspects. Thus, the main goal of this study was to investigate the current literature and discuss the association between the central nervous system and propofol abuse and addiction in the context of addictive behavior. Current data suggest that propofol has a strong addictive potential and produces prominent addiction in both animals and humans. Thus, medical practitioners should exercise caution with propofol use, and we argue that this drug should be added to the list of controlled substances.

Subanesthetic Dose of Propofol Activates the Reward System in Rats

BACKGROUND

Propofol has addictive properties, even with a single administration, and facilitates dopamine secretion in the nucleus accumbens (NAc). Activation of the dopaminergic circuits of the midbrain reward system, including the ventral tegmental area (VTA) and NAc, plays a crucial role in addiction. However, the effects of propofol on synaptic transmission and biochemical changes in the VTA-NAc circuit remain unclear.

METHODS

We investigated the effects of subanesthetic doses of propofol on rat VTA neurons and excitatory synaptic transmission in the NAc using slice patch-clamp experiments. Using immunohistochemistry and western blot analyses, we evaluated the effects of intraperitoneal propofol administration on the expression of addiction-associated transcription factor ΔFosB (truncated form of the FBJ murine osteosarcoma viral oncogene homolog B protein) in the NAcs in 5-week-old rats.

RESULTS

In the current-clamp mode, a subanesthetic dose (0.5-5 µmol/L) of propofol increased the action potential frequency in about half the VTA neurons (excited neurons: control: 9.4 ± 3.0 Hz, propofol 0.5 µmol/L: 21.5 ± 6.0 Hz, propofol 5 µmol/L: 14.6 ± 5.3 Hz, wash: 2.0 ± 0.7 Hz, n = 14/27 cells; unchanged/suppressed neurons: control: 1.68 ± 0.94 Hz, propofol 0.5 µmol/L: 1.0 ± 0.67 Hz, propofol 5 µmol/L: 0.89 ± 0.87 Hz, wash: 0.16 ± 0.11 Hz, n = 13/27 cells). In the voltage-clamp mode, about half the VTA principal neurons showed inward currents with 5 µmol/L of propofol (inward current neurons: control: -20.5 ± 10.0 pA, propofol 0.5 µmol/L: -62.6 ± 14.4 pA, propofol 5 µmol/L: -85.2 ± 18.3 pA, propofol 50 µmol/L: -17.1 ± 39.2 pA, washout: +30.5 ± 33.9 pA, n = 6/11 cells; outward current neurons: control: -33.9 ± 14.6 pA, propofol 0.5 µmol/L: -29.5 ± 16.0 pA, propofol 5 µmol/L: -0.5 ± 20.9 pA, propofol 50 µmol/L: +38.9 ± 18.5 pA, washout: +40.8 ± 32.1 pA, n = 5/11 cells). Moreover, 0.5 µmol/L propofol increased the amplitudes of evoked excitatory synaptic currents in the NAc, whereas >5 µmol/L propofol decreased them (control: 100.0 ± 2.0%, propofol 0.5 µmol/L: 118.4 ± 4.3%, propofol 5 µmol/L: 98.3 ± 3.3%, wash [within 10 min]: 70.7 ± 3.3%, wash [30 minutes later]: 89.9 ± 2.5%, n = 13 cells, P < .001, Dunnett's test comparing control and propofol 0.5 µmol/L). Intraperitoneally administered subanesthetic dose of propofol increased ΔFosB expression in the NAc, but not in VTA, 2 and 24 hours after administration, compared with the Intralipid control group (propofol 2 hours: 0.94 ± 0.15, 24 hours: 0.68 ± 0.07; Intralipid 2 hours: 0.40 ± 0.03, 24 hours: 0.37 ± 0.06, P = .0002 for drug in the 2-way analysis of variance).

CONCLUSIONS

Even a single administration of a subanesthetic dose of propofol may cause rewarding change in the central nervous system. Thus, there is a potential propofol rewarding effect among patients receiving anesthesia or sedation with propofol, as well as among health care providers exposed to propofol.

Sevoflurane addiction due to workplace exposure: A case report and literature review

RATIONALE

Anesthesiologists have a well-known increased risk of substance abuse. High-concentration of inhalation anesthetics in exhaled air of operating room personnel is detected. such secondhand exposure produces neurobiological sensitization to the reinforcing effects of inhalation anesthetics.

PATIENT CONCERNS

An addictive young male anesthesiologist who was long-term abuse with sevoflurane after 4 years occupational exposure. A 28-year-old anesthesiologist on duty was found deeply sleep in the locker room and coved his nose with Gauze with high-concentration of sevoflurane. He was found addiction to sevoflurane second time. Several life-threatening incidents occurred including severe aspiration pneumonia. No other addiction was found in his history before he became severely dependent on sevoflurane.

DIAGNOSES

A visual analog scale was employed to assess the severity of craving for sevoflurane and the Benzodiazepine Withdrawal Symptom Scale (BWSQ2)-scale was used to assess sevoflurane withdrawal syndrome(WS).

INTERVENTIONS

First time an opened original sevoflurane container filled with water instead of sevoflurane was handed out for a minute in order to elicit craving and withdrawal symptom in five therapeutic single-sessions. Second time an opened original sevoflurane container filled with sevoflurane instead of water was used as his powerful cur-stimulus and also was handed out for a minute.

OUTCOMES

After professional therapy and continuous surveillance he was rehabilitation and back to work. However, after three weeks he became addiction to sevoflurane again. He showed very sensitive to sevoflurane and switched to other career.

LESSONS

This case emphasizes that secondhand exposure to inhalation anesthetics may be dangerous and increase the life-threatening professional risk to anesthesiologists, although identification of the responsible factor remains difficult. However, the safety of operating room staff should be aroused wide-spread social concern.

Neurobiology of Propofol Addiction and Supportive Evidence: What Is the New Development?

Propofol is a short-acting intravenous anesthetic agent suitable for induction and maintenance of general anesthesia as well as for procedural and intensive care unit sedation. As such it has become an unparalleled anesthetic agent of choice in many institutional and office practices. However, in addition to its idealistic properties as an anesthetic agent, there is accumulating evidence suggesting its potential for abuse. Clinical and experimental evidence has revealed that not only does propofol have the potential to be abused, but also that addiction to propofol shows a high mortality rate. Based on this evidence, different researchers have shown interest in determining the probability of propofol to be an addictive agent by comparing it with other drugs of abuse and depicting a functional similitude that involves the mesocorticolimbic pathway of addiction. In light of this, the Drug Enforcement Agency and the American Society of Anesthesiologists have put forth certain safety recommendations for the use of propofol. Despite this, the abuse potential of propofol has been challenged at different levels and therefore the preeminent focus will be to further validate the linkage from medicinal and occasional use of propofol to its addiction, as well as to explore the cellular and molecular targets involved in establishing this linkage, so as to curb the harm arising out of it. This review incorporates the clinical and biomolecular evidence supporting the abuse potential of propofol and brings forth the promising targets and the foreseeable mechanism causing the propofol addiction phenotypes, which can be called upon for future developments in this field.

Propofol (2,6-diisopropylphenol) is an applicable immersion anesthetic in the axolotl with potential uses in hemodynamic and neurophysiological experiments

The Mexican axolotl (Ambystoma mexicanum) is an important model species in regenerative biology. Traditionally, axolotls are anesthetized using benzocaine or MS-222, both of which act to inhibit voltage gated sodium channels thereby preventing action potential propagation. In some neurophysiological experiments this is not desirable; therefore we tested propofol as an alternative anesthetic in the axolotl. We evaluated benzocaine, MS-222, and propofol's cardiovascular effects, effects on action potential propagation in the spinal cord, and gross limb regenerative effects. We found that propofol is applicable as a general anesthetic in the axolotl allowing for neurophysiological experiments and yielding a stable anesthesia with significantly less cardiovascular effect than both benzocaine and MS-222. Additionally, propofol did not affect gross limb regeneration. In conclusion we suggest the consideration of propofol as an alternative immersion anesthetic to benzocaine and MS-222.

Non-opioid anesthetic drug abuse among anesthesia care providers: a narrative review

PURPOSE

The objective of this narrative review is to provide an overview of the problem of non-opioid anesthetic drug abuse among anesthesia care providers (ACPs) and to describe current approaches to screening, therapy, and rehabilitation of ACPs suffering from non-opioid anesthetic drug abuse.

SOURCE

We first performed a search of all literature available on PubMed prior to April 11, 2016. The search was limited to articles published in Spanish and English, and the following key words were used: anesthesiology, anesthesia personnel, AND substance-related disorders. We also searched Ovid MEDLINE^® databases from 1946-April 11, 2016 using the following search terms: anesthesiology OR anesthesia, OR nurse anesthetist OR anesthesia care provider OR perioperative nursing AND substance-related disorders.

PRINCIPAL FINDINGS

Despite an increased awareness of drug abuse among ACPs and improvements in preventive measures, the problem of non-opioid anesthetic drug abuse remains significant. While opioids are the most commonly abused anesthesia medications among ACPs, the abuse of non-opioid anesthetics is a significant cause of morbidity, mortality, and professional demise.

CONCLUSION

Early detection, effective therapy, and long-term follow-up help ACPs cope more effectively with the problem and, when possible, resume their professional activities. There is insufficient evidence to determine the ability of ACPs to return safely to anesthesia practice after rehabilitation, though awareness of the issue and ongoing treatment are necessary to minimize patient risk from potentially related clinical errors.

Prevalence of Substance Abuse Among Oral and Maxillofacial Surgery Residents From 2006 to 2015

PURPOSE

Substance abuse in oral and maxillofacial surgery (OMS) training programs is an important and under-represented topic in the literature. This study's purpose was to assess the prevalence of substance abuse in OMS training programs in the United States during a 10-year period and to determine the substances most abused by OMS residents.

MATERIALS AND METHODS

A cross-sectional survey study was conducted by sending an online questionnaire to program directors and chairpersons of all OMS graduate training programs accredited by the Commission on Dental Accreditation. The content- and validity-tested survey asked respondents to report on substance abuse cases at their program from 2006 to 2015. Auxiliary questions asked opinions on substance abuse. To analyze the data, percentages were calculated, including the estimated prevalence of abuse; results were presented as bar charts.

RESULTS

Forty-six of the 101 OMS training programs (45.5%) responded. Sixteen of the responding 46 programs (34.8%) reported at least 1 suspected or encountered incident of substance abuse. The 2 most abused substances were alcohol and narcotics. During the decade studied, the prevalence of resident substance abuse was estimated to be 1.2%.

CONCLUSION

The estimated prevalence of resident substance abuse has gone unchanged since Rosenberg's initial study in 1986 (J Oral Maxillofac Surg 44:458, 1986). With the introduction of new drugs and despite more stringent protocols, substance abuse continues to be a germane issue for OMS requiring ongoing attention clinically and in the literature.

Lifetime psychiatric and substance use disorders among impaired physicians in a physicians health program: comparison to a general treatment population: psychopathology of impaired physicians

OBJECTIVES

The prevalence of substance abuse and other psychiatric disorders among physicians is not well-established. We determined differences in lifetime substance use, and abuse/dependence as well as other psychiatric disorders, comparing physicians undergoing monitoring with a general population that had sought treatment for substance use.

METHODS

Participants were 99 physicians referred to a Physician's Health Program (PHP) because of suspected impairment, who were administered the Computerized Diagnostic Interview Schedule Version IV (CDIS-IV) to assess the presence of psychiatric disorders. Referred physicians were compared with an age, gender, and education status-matched comparison group from National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) Wave 1, in a 1:1 ratio.

RESULTS

Although referred physicians did not differ from their counterparts on lifetime use of alcohol, opiates, or sedatives, they did have significantly higher conditional odds of meeting criteria for alcohol, opiate, and sedative The Diagnostic and Statistical Manual of Mental Disorders IV abuse/dependence disorders. Physicians referred to the PHP had significantly lower odds of obsessive-compulsive disorder, major depression, and specific phobia compared with their counterparts.

CONCLUSIONS

Physicians referred to a PHP have significantly higher odds of abuse/dependence disorders for cannabinoids and cocaine/crack compared with a matched general population sample that had ever sought treatment for substance use, even though physicians were less likely to report use of those substances. Although the rate of alcohol use was similar between the 2 populations, physicians had higher odds of abuse/dependence for opiates, sedatives, and alcohol. More research is needed to understand patterns of use, abuse/dependence, and psychiatric morbidity among physicians.

Mandatory naltrexone treatment prevents relapse among opiate-dependent anesthesiologists returning to practice

OBJECTIVE

Anesthesiologists with opioid use disorders are at high risk for relapse. In 2005, the impaired professionals monitoring program of the State of Florida implemented a policy whereby anesthesiologists referred for opiate use disorders were contractually obligated to take naltrexone for 2 years. Naltrexone ingestion was witnessed and verified via random urine drugs screens or administered via intramuscular injection.

METHOD

Charts were reviewed for the 11 anesthesiologists who underwent mandated pharmacotherapy with naltrexone, and 11 anesthesiologists who began monitoring immediately before implementation of this policy.

RESULTS

Eight of 11 anesthesiologists who did not take naltrexone experienced a relapse on opiates. Only 1 of 11 anesthesiologists experienced a relapse on opiates after taking naltrexone, whereas another relapsed on an inhalant (nitrous oxide). It is noteworthy that 5 of the 11 anesthesiologists who took naltrexone had relapsed before naltrexone treatment, and 7 of the 11 anesthesiologists who did not take naltrexone experienced multiple documented relapses. Only 1 of the 11 anesthesiologists who did not take naltrexone successfully returned to the practice of anesthesiology. This individual suffered primarily from alcohol dependence, and suspected opiate abuse was never verified. Others who attempted return to anesthesiology (n = 7) suffered a relapse. In comparison, 9 of the 11 anesthesiologists who took naltrexone have returned to the practice of anesthesiology without a relapse (as verified by continued random urine and hair testing).

CONCLUSION

Mandatory naltrexone treatment may provide anesthesiologists with an additional safeguard to successfully return to work.

Clinical physiology and mechanism of dizocilpine (MK-801): electron transfer, radicals, redox metabolites and bioactivity

Dizocilpine (MK-801), an extensively investigated drug possessing secondary amine and benzenoid functions, displays a wide array of biological properties, including anticonvulsant and anesthetic. There is scant discussion of biomechanism. A relevant, important finding is formation of oxidative metabolites in the hydroxylamine and phenolic categories. Analogy to cocaine metabolites suggests participation of redox entities, such as, hydroxylamine, nitroxide and nitrosonium, which can lead to electron transfer and radical formation. There is also similarity to metabolism by 3,3′-iminodipropionitrile and phencyclidine. Alternatively, the phenolic metabolites are well-known precursors of ET quinones. The review documents various physiological effects, mainly involving the central nervous system. Also of interest are the pro- and anti-oxidant properties. Considerable attention has been paid to MK-801 as an antagonist of the N-methyl-D-aspartate receptor in the glutamate category. This aspect is often associated with effects on the central nervous system. The review also provides recent literature dealing with MK-801/NMDA receptor in various areas of bioactivity. Studies were made of MK-801 involvement in working memory processing. Deficits in behavior were noted after administration of the drug. Treatment of mice with dizocilpine induced learning impairment. The influence of MK-801 on fear has been investigated. The substance is known to exert an analgesic effect in pain control. A number of reports deal with anesthetic properties.

Physician views regarding substance use-related participation in a state physician health program

Physician Health Programs (PHPs) safeguard the public by monitoring impaired physicians, but participation is not always voluntary, and many physicians resist referral. In this study, 80 physicians (85.1% male) who were referred to a state PHP for substance use-related problems completed an anonymous online survey regarding their experiences in the program. Results indicated that 78.1% of program completers had a 5-year contract, with 100% including random drug screening. In addition, 84.8% continued participation in 12-step fellowships after the required monitoring period. Participants were generally satisfied with the program, and 92.5% indicated that they would recommend it to others. They provided suggestions to increase the acceptability and efficacy of PHPs for physicians.