Systematic overview of co-proxamol to assess analgesic effects of addition of dextropropoxyphene to paracetamol
BMJ 1997; 315 doi: https://doi.org/10.1136/bmj.315.7122.1565 (Published 13 December 1997) Cite this as: BMJ 1997;315:1565
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Although Po and Zhang(1) are to be congratulated for their laborious
review of propoxyphene, this reader must agree with the comments of Prof
Hanks' et al comments(2) that caution the clinician to interpret the
results of predominantly single dose analgesic studies in light of the
common clinical experience of chronic, around-the-clock (time contingent
vs. symptom contingent administration). For years I had been frustrated by
my elderly patients' anecdotal reports of successful analgesia with
chronic propoxyphene therapy, since my reading of the (predominantly
single dose model) literature suggested that efficacy should not be much
greater, if at all, then over-the-counter preparations of "simple"
analgesics. Rather than disparage these innocents for not having read the
textbook, I ultimately came to make the intuitive leap advocated by Hanks
et al, i.e., that the pharmacokinetics associated with chronicity of use
may indeed be responsible for better than would otherwise be expected
results.
New work, however suggests that in addition to its classic, albeit
moderate opioid effects, propoxyphene exhibits additional activity at the
N-methyl-D-aspartate (NMDA) receptor,(3) as has also recently been
observed with methadone.(4) Activation of this receptor is held to
comprise an important alternative means to combat pain, especially in the
presence of injured nerves and/or opioid tolerance. This mechanism may
also contribute to disparate conclusions reached by scientists, clinicians
and finally, the ultimate arbiter, the patient. While it would be
unfortunate to persist treatment with a less highly regulated analgesic
that is inadequate based on a theoretical advantage and a reluctance to
advance to a more analgesic, the potential for additive or synergistic
effects, together with observations of efficacy with chronic use(5) may
ensure a persistent role for propoxyphene, at least until newer more
specific analgesics become available.
Richard B. Patt, M.D.
Director, The Patt Center for Cancer Pain & Wellness
Associate Professor, Anesthesiology and Neuro-Oncology
University of Texas M.D. Anderson Cancer Center
Octavio Calvillo, M.D., PhD.
Director, Pain Fellowship
Clinical Associate Professor of Anesthesiology
Baylor College of Medicine
(1) Li Wan Po A, Zhang WY: Systematic overview of co-proxamol to
assess analgesic effects of addition of
dextropropoxyphene to paracetamol. BMJ 1997;315:1565-1571
(2) Hanks GW, Forbes K: Co-proxamol is effective in chronic pain.
BMJ. 1998;316:1980.
(3) Ebert B, Andersen S, Hjeds H, Dickenson H: Dextropropoxyphene
acts as a noncompetitive N-methyl-D-aspartate antagonist. J Pain Symptom
Manage 1998;15:269-274.
(4) The d- and l-isomers of methadone bind to the non-competitive
site on the N-methyl-D-aspartate (NMDA) receptor in rat forebrain and
spinal cord. Neurosci Lett 1997;223:5-8.
(5) Dextropropoxyphene versus morphine in opioid-naive cancer
patients with pain. J Pain Symptom Manage 1998;15:76-81.
Competing interests: No competing interests
Disagree with result by Medical Profession
The study of co-proximal in a small amount of people, when in general
the study is minimal has caused the medical board to withdraw this drug
which in reality helps millions of people without side effect.
I know many people who have used this drug and without any side
effects and because of the decision taken, my friends and I now suffer
pain because the balance we had previous to alleviate intensity of pain
with a good balance of medication has been reduced and upset and has
resulted in causing myself to be even more crippled and in pain having no
longer access to the drug. Having tried various concoctions such as
tramadal, dihydracodeine, zamadol, co-codamol, none of these do a great
deal coupled with gabapentin whereas topping it up with co-proximal gave
me some quality of life and less pain.
People should do further far more indepth studies widespread in many
areas before they come to the one decision out of a over 2000 in a study.
There are more than 24 million people in the UK ! I had quality of life
on co-proximal, now i have less.
Kind regards
Jacqueline
Competing interests:
None declared
Competing interests: No competing interests