Decline in the Development of New Anesthetics

Differential effects of the novel neurosteroid hypnotic (3β,5β,17β)-3-hydroxyandrostane-17-carbonitrile on electroencephalogram activity in male and female rats

BACKGROUND

We recently showed that a neurosteroid analogue, (3β,5β,17β)-3-hydroxyandrostane-17-carbonitrile (3β-OH), induced hypnosis in rats. The aim of the present study was to evaluate the hypnotic and anaesthetic potential of 3β-OH further using electroencephalography.

METHODS

We used behavioural assessment and cortical electroencephalogram (EEG) spectral power analysis to examine hypnotic and anaesthetic effects of 3β-OH (30 and 60 mg kg-1) administered intraperitoneally or intravenously to young adult male and female rats.

RESULTS

We found dose-dependent sex differences in 3β-OH-induced hypnosis and EEG changes. Both male and female rats responded similarly to i.p. 3β-OH 30 mg kg-1. However, at the higher dose (60 mg kg-1, i.p.), female rats had two-fold longer duration of spontaneous immobility than male rats (203.4 [61.6] min vs 101.3 [32.1] min), and their EEG was suppressed in the low-frequency range (2-6 Hz), in contrast to male rats. Although a sex-dependent hypnotic effect was not confirmed after 30 mg kg-1 i.v., female rats appeared more sensitive to 3β-OH with relatively small changes within delta (1-4 Hz) and alpha (8-13 Hz) bands. Finally, 3β-OH had a rapid onset of action and potent hypnotic/anaesthetic effect after 60 mg kg-1 i.v. in rats of both sexes; however, all female rats and only half of the male rats reached burst suppression, an EEG pattern usually associated with profound inhibition of thalamocortical networks.

CONCLUSIONS

Based on its behavioural effects and EEG signature, 3β-OH is a potent hypnotic in rats, with female rats being more sensitive than male rats.

Recent History of Publication-Based Academic Interest in General Anesthetics

PURPOSE

The aim of this study was to determine how interest in various general anesthetics among the authors of academic publications changed over the past 50 years.

METHODS

Publication-based academic interest were analyzed using specific scientometric indices: popularity index (PI), top journal selectivity index (TJSI), and index of change (IC). Terms used for searches were the names of drugs belonging to two pharmacological classes of general anesthetics - inhaled and intravenous. Only those that had a PI value > 2.0 during at least one of the 10 five-year periods, from 1967 to 2016, were selected.

RESULTS

The PI, an index of comparative popularity, reflects a consistent decline in academic interest over time in both classes of general anesthetics. Over the past 25 years, the PI of inhaled anesthetics decreased by 52 %, and that of intravenous anesthetics fell by 32%. At the same time, the PI of anesthesia management increased by 167%. Among individual anesthetics, the most impressive change was a profound decline in halothane's PI, from 22.9 in 1972-1976 to 0.5 in 2012-2016. The interest in halothane was gradually supplanted by that in new agents, initially by enflurane, followed by isoflurane and finally, sevoflurane. The next meaningful change was the gradual rise in sevoflurane's PI to surpass that of isoflurane. The most dramatic change among the PIs of intravenous anesthetics was associated with the introduction of propofol: an increase from 1.8 to its maximum of 13.6.

CONCLUSIONS

The study revealed a constant decline over time in academic interest in the pharmacological basis of general anesthesia relative to all fields of anesthesia combined.

Changes in Publication-Based Academic Interest in Local Anesthetics Over the Past 50 Years

PURPOSE

To present the history of changes in academic interest in local anesthetics quantitatively.

METHODS

The changes in publication-based academic interest in local anesthetics were assessed using information from the database of PubMed. The assessment was mostly based on the following indices: general popularity index (GPI), representing the proportion of articles on a drug relative to all articles in the field of regional anesthesia, and specific popularity index (SPI), representing the proportion of articles on a drug relative to all articles in one of the four forms of regional anesthesia: local anesthesia, spinal anesthesia, epidural anesthesia, and peripheral nerve blocks.

RESULTS

The most important general feature of the changes in publication-based academic interest in local anesthetics for the past 50 years was the concentration of this interest on a very limited number of drugs. By 2010-2014, only three anesthetics demonstrated the GPI value above 4.0: bupivacaine (10.1), lidocaine (10.0), and ropivacaine (4.6). All other local anesthetics had GPI declining mostly to less than 1.0 (2010-2014). The rate of change in publication-based academic interest was very slow in both its increase and decline. The most profound change in publication-based academic interests was caused by the introduction of bupivacaine. During a 20-year period (from 1965-1969 to 1985-1989), bupivacaine's GPI increased from 1.3 to 12.9.

CONCLUSION

A slowly developing concentration of publication-based academic interest on a very limited number of local anesthetics was the dominant feature related to this class of anesthetic agents.

Opioid prescriptions for pain and epidemic of overdose death: can the dramatic reduction in anesthesia mortality serve as an example?

The annual number of US deaths from prescription-opioid overdose quadrupled between 1999 and 2010 and in 2010 alone reached 16,651. Deaths from opioid overdose have now surpassed the historic death toll from another drug-related epidemic - anesthesia mortality. In 1954, Beecher and Todd published reliable data on anesthesia-related mortality in the US, estimating the annual number of deaths to be nearly 5,000. Presently anesthesia/anesthetics are reported as the underlying cause in approximately 34 deaths in the US annually. This spectacular decline in anesthesia-related mortality could serve as an example for attempts to curb the epidemic of opioid overdose death. The main reason that led to the dramatic decline in anesthesia-related mortality is the context in which anesthetics are used. It includes training of the anesthesia providers, the introduction of specific standards of patient safety, and anesthesia monitoring. I suggest that the introduction of a similar multifactorial proper context for the use of opioids in the treatment of chronic nonmalignant pain might be the same "game changer" it was for safety in anesthesia.