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Fentanyl


patsummers
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I ran across this little article I'm not sure how but it really sounds interesting let me know if it doesn't work and I'll repost it 

Letters Vol. 30 No. 1 July 2005
In theory, two logical approaches are available
to change the dose of transdermal drug delivery
from a fixed-rate and fixed-size patch. A straight-
forwardmethodis toreducethedrugreleasedby
cutting the permeable membrane into a smaller
size. This is not feasible with the reservoir patch,
however, because of the potential damage to its
releasing mechanism. A more reliable approach
is to control the rate of absorption. We present
a simple method for adjusting drug absorption
using the fixed delivery rate patch.
In this procedure, an occlusive dressing was
inserted between the patch and the skin, which
can block the contact area of the skin. We used
a 6 7-cm adhesive OpSite adhesive film
(Flexigrid, Smith-
Nephew, London, UK), a
waterproof and elastic polyurethane film
dressing. It contains a transparent cover and
lines depicting quadrates of 1 cm2 (1 1 cm).
Based on the fixed drug-releasing rate of
2.5 µg/hr/cm2
, we cut a designated size (i.e.,
4 cm2 for 10 µg/hr absorption) on the intact
OpSite film with either a knife or scissor. The
film was applied to the skin and then covered
with a TDF patch. As the OpSite film was
larger than the patch, it served as a shutter that
blocked the drug absorption within its bound-
ary but allowed for a designated amount of drug
release through the predetermined open space.
Comment
By adjusting the area of the absorption sur-
face, the above-described method provides an
adjustable dose of TDF between 0 to 25 µg/hr
without damaging the microporous membrane
and drug reservoir. With precise control of
the contact skin area, we are able to prescribe a
mini-dose patch for children and to titrate the
dose in a semi-linear progression fashion. This
method does not require complicated calcula-
tions or expensive equipment. We believe that
any adhesive, thin, and waterproof plastic
sheet that is able to block the penetration of
fentanyl citrate can be used as a substitute. Tight
adhesion at the margin of the occlusive dressing
avoids a significant error in area calculation.
Another advantage of this method could be
the prolongation of the duration of the anal-
gesic effect of the TDF patch, which would
occur because a lesser amount of drug is being
consumed. Based on simple calculation, we can
assume that a doubling of duration of effect
could be expected in a 25 µg/hr patch when
the absorption rate is reduced to 12.5 µg/hr.
In our preliminary experience with 126 pa-
tients, some patients did not require patch re-
placement until the 4th or 5th day, a time
period longer than 72 hours.7 Even with careful
calculation of the initial TDF dose, 70 patients
(56%) had tried to reduce the initial dose set
by the oral-to-patch conversion ratio. As a re-
duction of dose was welcomed by 56% of our
patients, the idea of this method can serve as
a patient-controlled titration for TDF. Our clini-
cal observation needs to be correlated with
pharmacokinetic studies that are to be under-
taken in the future.
A matrix-based patch will soon be commer-
cially available throughout the world. These
patches can be readily cut into any indicated
size for dose titration and may thus obviate the
need for our approach. However, a drawback
of cutting a patch is the potential waste in drug.
With the reservoir intact, the total amount of
drug is not lost. Instead, our preliminary data
have shown an extension of the regular permis-
sive day of patch application (i.e., 3 days) and
may thus reduce the cost for such an expen-
sive material.
Yu-Ren Peng, MD
Wei-Zen Sun, MD
National Taiwan University Hospital
Taipei, Taiwan
Martin S. Mok, MD
Taipei Medical University
Taipei, Taiwan
doi:10.1016/j.jpainsymman.2005.05.002
References
1. Mercadante S, Villari P, Ferrera P. Clinical prob-
lems with transdermal fentanyl titration from 25 to 50
µg/hr. J Pain Symptom Manage 2001;21(6):448–449.
2. Janssen Pharmaceutica. Full U.S. prescribing
information of Duragesic. Janssen: Beerse, Belgium,
2000.
3. Janssen Pharmaceutica. Full U.S. prescribing
information of Duragesic. Janssen: Beerse, Belgium,
2004.
4. Collins JJ, Dunkel IJ, Gupta SK, et al. Transdermal
fentanyl in children with cancer pain: feasibility,
tolerability, and pharmacokinetic correlates. J Pedi-
atr 1999;134(3):319–323.
5. Hunt A, Goldman A, Devine T, et al. Transdermal
fentanyl for pain relief in a pediatric palliative care
population. Palliat Med 2001;15:405–412.
6. Hardwick WE, King WD, Palmissano PA. Respira-
tory depression in a child unintentionally exposed
to transdermal fentanyl patch. South Med J 1997;
90:962–964.
7. Peng Y-R, Sun W-Z. A novel approach to produce
mini-titration of Duragesic patch. Acta Anaesthesiol

I think that did it although it may be somewhat truncated had a copy and paste the whole damn thing.

https://www.jpsmjournal.com/article/S0885-3924

PIIS0885392405002381 (1).pdf

Edited by patsummers
attachment didn't work, had any of these to work so I may try another method when I determined I usually find a way around it . 2 add it again
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