We asked lead editor Pierre Beaulieu for his thoughts
on this exciting and timely topic.
Q: What is the main focus of your own research, and how do
you divide your time between research, clinical work, and
teaching?
A: My main research interest lies in the pharmacology of cannabinoids in
the treatment of pain. More specifically, my attention is focused on the
mechanisms of neuropathic pain (in animal models) and on how the
endocannabinoid system can be modulated in that condition. As a
clinician, I also have great interest in the pharmacology of drugs that
can reduce pain in the perioperative period, more specifically local
anesthetics and nonsteroidal anti-inflammatory drugs (NSAIDs) in
addition to cannabinoids. My time is divided between research activities
(40%), mainly in the department of pharmacology, where I have a pain
lab; my clinical work as an anesthesiologist (40%); and finally, my
teaching activities at the Université de Montréal (20%).
Q: Why did you and your coeditors decide to put together a
book on the pharmacology of pain?
A: Initially, David Lussier and I came up with the idea because
we wanted to fill a gap in the literature. There are many interesting
books published by IASP Press, but we thought that a volume dedicated to
pain pharmacology was necessary in view of the many recent advances in
the field. Indeed, a book series edited by Anthony Dickenson was
available in the 1990s, but this field is evolving so rapidly that we
were sure that a new book was a priority for the pain community, and
indeed for everyone involved with patients in pain. Frank Porreca, as a
leading expert in the field of pain pharmacology and also section editor
for PAIN, was the perfect person to complete the team. Therefore, the
idea of a book offering an overview of current drug treatment for pain
was launched.
Q: How does this book differ from other pharmacological texts
that cover analgesics and adjuvant medications?
A: Although it is to be expected that most textbooks are
written by experts, I have to say that for this particular book we have
been able to involve the leading international experts in the field, so
that excellence is the first thing that comes into my mind when you ask
me how it is different from other books. Second, it is rare to find a
book dedicated to the pharmacology of pain. Pain textbooks have a
section on pharmacological treatments, but our book is solely dedicated
to pain pharmacology, which gives us the necessary depth to be
exhaustive on this topic. Another point is the structure of each
chapter. Authors have been asked to integrate into their chapter some
meaningful clinical data in order to cover both basic and clinical
pharmacology. Furthermore, we have dedicated a whole section of the book
on clinical pharmacology of pain in specific patient groups. The book
also covers special topics such as the pharmacology of tolerance,
dependency and addiction, pharmacogenetics, and models of pain.
Q: In what ways has our knowledge of the mechanisms of pain
improved in the past few decades?
A: There has been tremendous progress in the understanding of pain
mechanisms in that time frame. You only have to look at the number of
publications in the field, the number of new pain journals, and the
interest of the scientific community. To give a few examples, consider
the discovery of the crucial role played by glia in the pathophysiology
of pain, the finding of new pain pathways, the demonstration of how
descending facilitation and inhibition modulate pain signals, and the
recent breakthrough in uncovering the role of the transient receptor
potential family of receptors.
Q: Have the options for pain treatment changed significantly
over this time frame?
A: Yes, indeed. The number of potential pain targets has increased
dramatically, as is illustrated in Part II of the book, which covers 14
different approaches to (or targets in) pain treatment. Furthermore,
Andy Dray and Martin Perkins have summarized in their chapter the latest
developments in ongoing clinical trials using new analgesics.
Q: Do you think we will see new classes of analgesics emerge
in the near future?
A: I hope so, but we have to consider that recent times have been
disappointing. Indeed, we are still largely counting on
“old” drugs such as acetaminophen, NSAIDs, and opioids to
treat most pain syndromes. Analgesic antidepressants and anticonvulsants
have been used in the last few years to treat neuropathic pain, but
again, these drugs are not really new. Thus, despite a real potential
for new avenues in pain treatment, we are still eagerly awaiting new
classes of analgesics, knowing that a magic drug does not exist and that
multimodal analgesia (the simultaneous use of more than one family of
analgesics to increase efficacy and to decrease side effects) is crucial
to obtain better results. But to come back to your question, I am
certain that new classes of analgesics will emerge, but it will take
time.
Q: What about new methods of administering existing
agents?
A: This is a critical area to consider because it is important to allow
optimal delivery of analgesics and at the same time do it in the most
innocuous way. For example, a recent method is the transdermal route of
administration, especially for the delivery of opioids (e.g., fentanyl
or buprenorphine). More sophisticated methods to increase the absorption
of analgesics using a small electric current (iontophoresis) through the
skin have also been developed. These methods are encouraging, and others
should be investigated.
Q: Reading this book has made me aware of the tremendous
complexity of pharmacological targets: the cyclooxygenase pathway,
opioid and cannabinoid systems, ion channels, neurotransmitters,
cytokines, and other receptors. Is it even possible for any one drug to
be effective against pain?
A: The answer is no! Some current drugs such as opioids are effective in
a large number of situations, but at the expense of troublesome or even
life-threatening side effects. As I have already mentioned, the
complexity of pain targets is now obvious, and no one magic bullet with
be able to address them all. Multimodal analgesia again comes into play
because it can tackle many targets with limited side effects.
Q: Placebo analgesia must always be accounted for in clinical
research. Are new findings emerging about its mechanisms?
A: Placebo analgesia, like the rest of the field, has evolved
tremendously in the last few years. The mechanisms involved in placebo
analgesia are much better understood, thanks to new findings that are
presented by Pierre Rainville and Serge Marchand’s team in one of
the chapters of the book. This area is fascinating, and it was a real
pleasure and very exciting to read the latest on that topic. I cannot
resist letting you read some of the conclusions made by the authors in
this chapter: “Recent studies suggest that the placebo effect is
present in many clinical interventions and that it can be, in some
cases, very powerful. We now know that the placebo effect depends on a
variety of neurochemical and neurophysiological mechanisms, which are
measurable and modifiable. This means that the placebo response must not
be seen as an indication of weakness or malingering and should not be
used to diagnose psychosomatic illness.”
Q: The book includes a section on specific patient groups,
including obstetric patients, older persons, infants and children, and
obese patients. What’s your philosophy on tailoring a treatment to
the individual patient?
A: We are very pleased to include these sections because they are rarely
covered in a book, and also because, as you mentioned, drug treatment
must be tailored to the individual patient. This is not a philosophical
point: it is becoming hard science! Examples are given in the chapter on
“Pharmacogenetics of Pain Inhibition” by Jeff Mogil, as well
as in the specific clinical section you mention. Indeed, a child and an
elderly person do not have the same pharmacology, and neither does an
obese person or a childbearing woman, but these people are seen and
managed every day by pain physicians and general practitioners. Thus,
data concerning these populations and how to manage them are of great
importance.
Q: In making the book so very accessible and useful for pain
clinicians you are potentially helping many patients receive the very
best pain care. Any final comments?
A: One final comment: writing a book on pharmacology of pain
does not mean that other pain treatments are obsolete or uninteresting.
On the contrary, I firmly believe that other approaches are crucial
(including physical activity) and are not in the shadow of
“hard” pharmacology. I will even encourage experts in that
field to write a book on these topics, like the latest book published by
IASP Press by Kathleen Sluka. Thank you for the opportunity to express
myself here.
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