Download neuropathic pain - topical treatment concepts

NEUROPATHIC PAIN - TOPICAL TREATMENT CONCEPTS
Drugs that can be used in compounding formulations for the treatment of Neuropathic pain.
Drug
Topical Application
Dose Range
Classifications
Mechanism of Action
Amitriptyline
2-5%
Antidepressant/Sympatholytic
Antidepressants block the reuptake of
noradrenaline and 5 - hydroxytryptamine (5HT);
has direct and indirect actions on opioid receptors,
inhibits histamine, cholinergic, 5HT and N - MethylD- Aspartate glutamate receptors; inhibits ion
channel activity and blocks adenosine uptake.
Bupivacaine
0.5-0.75%
Anesthetic-Nerve Pain
Stabilizes neuronal membrane by inhibiting the
ionic fluxes required for the initiation and
conduction of impulses.
2-5%
NMDA / Sodium Channel Blocker
Has shown real promise in dealing with painful
Neuropathy.
0.1-0.2%
Alpha-2 Agonist
5-10%
NMDA / CA Channel blocker
Carbamazepine
Clonidine
Dextromethorphan
Blocks the effect of Norepinephrine at alpha
receptors that have become hyperexcitable in the
neuropathy process.
Useful agent in the treatment of painful
neuropathy. May be given orally 300mg three
times a day.
The exact mechanism of action is not clear, but it
has shown some success in the treatment of
neuropathy both topically and systemically.
Gabapentin
6-10%
Glutamate Antagonist
Guaifenesin
10%
Skeletal Muscle Relaxer
5-10%
NMDA Antagonists
10%
NSAID
Nonsteroidal anti-inflammatory drug. Acts
peripherally to reduce the production of
prostaglandins that sensitize nerve endings at
the site of the injury, generating analgesic
effects..
Lidocaine
2-10%
Anesthetic-Nerve Pain
Stabilizes neuronal membrane by inhibiting the
ionic fluxes required for the initiation and
conduction of impulses.
Loperamide
5-7%
Mu Agonist
Ketamine
Ketoprofen
Acts as a skeletal muscle relaxer topically in
concentration of 10%.
When applied topically, Ketamine has shown
substantial promise for decreasing the pain of
Neuropathy. It is a noncompetitive antagonist of NMethyl-D-Aspartate receptors in the peripheral
nerves. Can be given orally 250mg at bedtime.
Acts like an opioid topically in a minimum
concentration of 5%.
Morphine
5-30%
Mu Agonist
Opioid receptors are present on the peripheral
terminal of thinly myelinated and unmyelinated
cutaneous sensory fibers. Systemic use of opioids
has caused adverse effects; therefore, the topical
application of opioids with fewer systemic effects
is an alternative.
Nifedipine
2-16%
L-Type Calcium Blocker
Topically, Nifedipine produces an anti-ischemic
effect by blocking calcium influx into cells, thereby
decreasing vascular tone and increasing blood
flow.
max 160mg / day
Orphenadrine
5-10%
NMDA / L Ca+ Channel Blocker
Pentoxifylline
5-10%
TNF-1 Alpha Antagonist
Used for its ability to enhance blood flow by
reducing blood viscosity.
Tetracaine
2-10%
Anesthetic-Nerve Block
Stabilizes neuronal membrane by inhibiting the
ionic fluxes required for the initiation and
conduction of impulses.
Has been used as an antiparkinsonism,
Antispastic and Analgesic drug for many years.
Conclusion:
As we learn more about the biochemical and pathophysiologic mechanisms of pain, we can develop targeted strategies for specific
conditions. Historically, treatment with Ketamine, Ketoprofen and Clonidine in PLO gel is initiated, then one or more drugs are
added if needed. Combination therapy is the most effective approach for managing the complex array of chemical mediators and
other contributors to the individual's pain experience. Topical formulations can provide effective therapy with fewer systemic adverse
drug effects and drug-drug interactions.
R-8/07