dvances
in pain treatment can be broken down into two distinct
areas: pharmacological advances and procedural-based
innovations. Both areas are critical to improving
patient outcomes and quality of life.
I. Advances in Pharmocological Treatment
There are several new advances in the pharmacological
treatment of pain that utilize novel delivery mechanisms
for pain medications. At the ASA 2006 Annual Meeting
in Chicago last October, several new or upcoming
additions to our armamentarium were introduced,
including:
• An inhaled liposome-encapsulated fentanyl
preparation (AeroLEF);
• A new oral transmucosal fentanyl tablet
(Fentora);
• A transmucosal patient-activated bolus
of fentanyl (E-trans);
• Intranasal morphine (Rylomine); and
• Intranasal ketamine (PMI-150).
AeroLEF is an investigational fentanyl product
that is delivered via an inhaled nebulized treatment.
It is indicated for moderate to severe pain. The
inhaled liposome-encapsulated fentanyl provides
rapid analgesia and extended duration of analgesia
whereby the lung serves as a reservoir for prolonged
effect. Though this drug is in the initial phase
of clinical studies in Canada, clinical trials are
planned for the United States in the very near future.
It affords patients the ability to self-titrate
their analgesia. This mode of delivery may be of
use in terminally ill patients for whom potent analgesics
need to be administered or in patients who cannot
use the oral route of administration.
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Rylomine is an intranasal delivery system for morphine
that is intended to target a niche portion of the
opiate market where rapid onset of analgesia is
needed without the need for intravenous access.
It provides faster onset of action than oral morphine
products, and since it bypasses the gastrointestinal
(GI) system, it is associated with fewer GI side
effects.
The E-trans fentanyl system is an on-demand delivery
mechanism that allows patients to deliver fixed
bolus doses of fentanyl of 40 micrograms each through
the skin. It utilizes a low-intensity direct current
to move fentanyl from a hrogel reservoir into the
skin, which has been shown to be as effective as
intravenous-PCA morphine. It does not incorporate
a continuous infusion.
Intranasal ketamine is an NMDA receptor antagonist
indicated for acute moderate to severe pain. The
doses required to treat pain are 1/10th to 1/16th
of those used for general anesthesia. This is currently
in clinical development. Off-label use and previous
studies have suggested ketamine is an effective
analgesic. Its initial market will be breakthrough
pain in orthopedic injuries and postoperative pain
where immediate-release opioids are desirable.
Fentora is a fentanyl buccal tablet that is partially
absorbed through the mouth and partly absorbed through
the stomach. It has incremental doses from 100 micrograms
to 800 micrograms. It is intended for breakthrough
pain in cancer patients similar to fentanyl lozenges
(Actiq).
These novel compounds will offer further options
in the care of our patients.
II. Procedural-Based Innovations
The use of interventional procedures can be instrumental
in improving outcomes for those suffering from chronic
pain. In the past few years, pain physicians have
been given many new tools to use in the battle against
pain. New advances are important, and physicians
should be aware of these issues when seeing these
patients in their office. Particular areas of interest
include:
• Spinal cord stimulation;
• Intrathecal drug delivery;
• Minimally invasive disc procedures; and
• Laser-guided fluoroscopy.
Spinal cord stimulation received initial Food
and Drug Administration (FDA) approval in the late
1960s. For several decades, the devices consisted
of simple anode and cathode arrays that delivered
energy at a constant voltage with minimal choice
in lead array. Over the past two years, innovations
have occurred in several areas of computer technology.
These advances include new leads that create a multitude
of possibilities for stimulating nerves. The most
advanced area of programming includes a new tripole
system that focuses cathode energy to the center
of the spinal cord. Other exciting areas include
rechargeable batteries, independent electrode programming
and constant current systems.
Intrathecal drug delivery has been used clinically
for more that two decades. The advances in recent
years have consisted of smaller pumps with equal
or larger volumes, improvements in software programming
and new research into more durable catheters by
several manufacturers. The biggest advance during
the last 24 months has been the approval by the
FDA of ziconotide for intrathecal use. This drug,
which is derived from a snail toxin, works at the
calcium channels to improve neuropathic pain. This
is the first drug to receive FDA approval for intrathecal
use in more than a decade.
Minimally invasive disc procedures have been a focus
of extensive research over the past few years. Advances
include new heating probes to treat the annulus,
new methods of mechanically removing the nucleus
and cutting-edge laser-based techniques to treat
complex disc, bone and nerve disorders. These advances
may lead to a reduction in the need for costly and
risky open surgical techniques.
New technology has allowed for the placement of
needles and other tools under fluoroscopic imagery
guided by lasers. These new fluoroscopic machines
allow for a laser to show the angle of the beam
both on the skin and on the X-ray. This technology
makes procedures much more efficient, allows for
immediate angle correction and may improve safety.
New advances in the treatment of pain will continue
over the coming years. It is the responsibility
of those practicing medicine to stay abreast of
these developments by reading peer-reviewed journals,
attending continuing medical education-accredited
meetings and sharing information with their colleagues.
ASA will strive to be a critical part of this advancement
and exchange of information.
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Timothy R. Lubenow, M.D., is Professor of Anesthesiology,
Rush Medical College, and Director, Section
of Pain Medicine, Rush University Medical Center,
Chicago, Illinois. |
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Timothy R. Deer, M.D., is President and CEO,
The Center for Pain Relief, Charleston, West
Virginia. |
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