Life Sci. 2006 Aug 2; [Epub ahead of print]
Examination of the interaction between peripheral diclofenac and gabapentin on the 5% formalin test in rats.
Picazo A, Castaneda-Hernandez G, Ortiz MI.
Putting 5 capsules of 300 mg gabapentin in a 60 ml bottle of Pennsaid may triple its analgesic power…
The actual study was done with the diclo-gaba injected subcutaneously so not exactly topical.The Gabapentin – Diclofenac mix had 3 times the analgesic effect of either separately.
With a vehicle like DMSO(in Pennsaid) the penetration should be somewhat like subcutaneous.
Note – I did studies to see how well 1% lidocaine in 50% DMSO would work – it takes 30 minutes to topically numb an area and I am not convinced phonophoresis (ultrasounding it)or ionophoresis improves that. So if you want top level effect to a spot – tape a cotton ball to area(do that first as once wet will not stick) and soak ball and leave on 30 minutes – irritation of skin was always a problem and steroids creams were useful there.
The ratio of Diclo to Gaba was 1:1.5 so theoretically if you took the commercial topical Pennsaid (1.5 % Diclofenac in 50% DMSO) – 60 mls. bottle and added 5 caps of 300 mg gabapentin (actually amount is 1.35 gm but this is close) – you should triple its effectiveness – DMSO is such a good solvent you would not have to use powdered gagapentin – just out of the capsules. If wanted to use other vehicle, that would be something like 1.5% Diclofenac and 2.25% Gabapentin. Anyone using such a mix?
try betacaine on the fingers. It is pricey and maybe sensitizing but sometimes very effective.
Obstet Gynecol. 2008 Sep;112(3):579-85.
Topical gabapentin in the treatment of localized and generalized vulvodynia.
Boardman LA, Cooper AS, Blais LR, Raker CA.
used 6% gabapentin in Lipoderm
Had to dissolve the gabapentin in ethoxy diglycol then mix with lipoderm – hopefully compounding pharmacy knows how
Gabapentin does not dissolve in Ethoxy Diglycol. It’s not soluble in DMSO, propylene glycol, alcohol or glycerin either. Solubility is critical for absorption because particle less than 1 micron (nanoparticle) will pass across the stratem corneum. Gabapentin will only dissolve in water at a 10% concentration. to increase solubility you have to acidify the solvent (water) below a pH of 5. PCCA, the manufacturer’s of Lipoderm, incorporate water into their transdermal base.
Was using plain Pennsaid one someone with sore bunions – not working – added the gabapentin and she felt fine – guess does work.
admin
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I was just prescribed this for such debilitating, middle back pain very near my spine (I have sever RA). Nothing helped me; i couldn’t even sit with stabbing, burning pain. Then I tried this mix from my pain doctor. it’s a miracle for me. Who knew? I’m looking into what exactly is in this stuff.. Incredible!
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From Admin:
It sounds like the skin nerves are involved if topical meds worked so well. The skin nerves can be calmed down by injecting dilute sugor overtop of them. It is called neural prolotherapy because author originally used strong sugar but now it is just more a nerve desensitization procedure using 5% Dextrose (IV sugar water) . Adding 3% glycerin (by volume) helps it last longer. The nerves can actually be felt in the skin and if 1 ml injected superficially to them every 2 centimeter (4/5 inch) or so can calm them down some – needs to be repeated weekly for average 6 times for more permanent effect. I have just finished a blog note about it here: (note the skin nerve need to be tender in order for injections to help)
Remarkable New Treatment – Injecting Over Tenderized Skin Nerves With Plain 5% Dextrose
http://painmuse.org/?p=3579
Glad you are some better
Happy New Year!